[HN Gopher] A speaker placement tip that speaker manuals get wro...
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A speaker placement tip that speaker manuals get wrong (2017)
Author : ZeljkoS
Score : 145 points
Date : 2021-01-15 09:12 UTC (13 hours ago)
(HTM) web link (sonicscoop.com)
(TXT) w3m dump (sonicscoop.com)
| waynesonfire wrote:
| this is the type of article that made me season my cast iron with
| flaxseed oil. some rando internet guy telling you things.
| omegote wrote:
| I was (and still am) in the same situation as the author two
| years ago. I bought a pair of JBL LSR 305 that I placed at each
| side of the screen, roughly 120cm away from each other and at
| arms length from me. They're about 30cm away from the back wall.
|
| The problem I have is with the bass. Standing in the normal
| position to interact with my PC, the bass strength is low. Now,
| the moment I move back about 1 meter, the bass strength becomes
| great (the one I'd expect from this pair of speakers).
|
| I really don't know what to do :/
| grandinj wrote:
| You're probably in a room null when in your "normal position to
| interact with the PC". Try moving them closer to the back wall.
| Or there are room treatments like adding some kind of
| absorption panel to the problematic wall(s).
| scns wrote:
| You can't trick physics. There are notes so low (huge
| wavelength), you can only hear them, if you are several meters
| away.
| jpitz wrote:
| What would be an example of such a note?
|
| Low E has a wavelength of a couple meters, no problems
| hearing that close up.
| colanderman wrote:
| Waves don't work like that. Otherwise it would be impossible
| to hear bass through (good) headphones.
|
| The issue is that, because of reflections, waves whose
| wavelengths are on the same order of magnitude as the
| distance from the speakers to the wall are getting cancelled
| out, depending on where you listen from. It is a well-known
| phenomenon.
|
| (Higher frequencies which are multiples of the missing bass
| frequencies will also be attenuated, but this is less
| immediately noticeable.)
| johnvanommen wrote:
| Actually, sound DOES work like that.
|
| For instance, if OP has his speakers located 57cm / 22
| inches from the back wall, there is going to be a very deep
| null at 150Hz, due to the reflection from the back wall.
| (150Hz is 227cm long.)
|
| If OP is listening in the nearfield, that dip will be
| obnoxious.
|
| On the other hand, if OP is listening at a distance of two
| meters, the dip will be LESS obnoxious because there will
| be dozens of dips and peaks in the response, contributing
| constructive and destructive interference, simultaneously.
|
| This is one of the reasons that loudspeakers are generally
| measured under two conditions:
|
| 1) very very close. For instance, a woofer can be measured
| with the microphone less than a centimeter from the cone
|
| 2) But the preferred method of getting a full range
| measurement is to measure the speaker outside, far away
| from any reflective surfaces.
| colanderman wrote:
| > there is going to be a very deep null [...] due to the
| reflection from the back wall
|
| That's exactly what I said.
|
| I read the grandparent to imply that distance from the
| source was the _only_ factor, that one needs to be a
| certain distance from a source to hear bass frequencies
| _at all_ , which I'm sure you'll agree is incorrect, as
| we both seem to have a correct understanding of the
| physics involved.
| ssssss777 wrote:
| If it's a room mode, you might experiment with where your desk
| is in the room and by extension where your ears end up being
| within that space. Or add a subwoofer whose placement you can
| optimize independently from your speakers.
|
| Taken to the extreme is the "Geddes Approach" which use
| multiple subwoofers placed around the room and lots of EQ
| provide a smooth low frequency response at the listening
| position.
| dsr_ wrote:
| Take a look at the back of your LSR305. There's a switch marked
| LF Trim. (There's also a HF Trim.) It has three positions: cut,
| normal, and boost. It's a built in EQ designed for handling
| room boundaries.
|
| You'll need to set it on both speakers.
| 52-6F-62 wrote:
| This, plus you could place isolation pads underneath the
| speakers to prevent the low frequencies from causing
| resonance in the desk or other platform they're on if they
| aren't already. You can find some pretty cheap options these
| days that should do the trick.
| bombcar wrote:
| Try moving one speaker back and forth - they may be angled such
| that the different phases are canceling bass right where you
| sit.
| hudo wrote:
| First thing about most HIFI speakers is that they have to be at
| least 0.5m from the back wall. Otherwise you lose sound stage
| depth and get bloated bass. Its such a shame to see people giving
| 5-10k$ on pair of really good speakers and putting them 20-30cm
| from the wall (i see that ALL the time on various FB groups). I
| have mine floorstanders around 1.2m away, where they sound the
| best. Is always a compromise between room and speakers placement.
| bzzzt wrote:
| Depends on the speakers I think. My floor standing speakers
| have front-firing woofers so putting them close to the wall
| doesn't matter that much for the sound.
| asdfjkhjhu33 wrote:
| This article does not mention that _scientific measurement_ with
| a _calibrated measurement microphone_ can take all of the
| guesswork out of speaker placement, just like you need a
| calibrated color measurement puck (and associated color-
| management software) to guarantee accurate color on computer
| monitors and printers. A measurement microphone tells you if the
| 200Hz frequency is too loud or too quiet with respect to the
| 1000Hz frequency, and so on, just like color management tells you
| if red #FF0000 is oversaturated or undersaturated with respect to
| the sRGB or DCI-P3 or whatever color space you are targeting. I
| bought a UMIK-1 microphone, downloaded the factory .txt
| calibration file, and used the roomeqwizard.com software to tune
| my systems. Works great. Human audible sound travels in waves at
| frequencies in the 16Hz-20KHz range. Those waves bounce around
| the room and interact to make certain frequencies louder and
| others quieter ( "standing waves"). This _room response_ is
| especially important below 250-500Hz: search for "Schroeder
| Frequency" if curious.
| baq wrote:
| denon's/marantz mid-range and above AVRs have audyssey which is
| allegedly quite good. any opinions on this solution compared to
| what you did?
| iuweiru8787 wrote:
| I am the OP but I threw out my throw-away account. I don't
| use consumer AVRs; I use pro-audio equipment for producing
| the content consumed on consumer AVR equipment. I tried some
| of these fancy boxes that you upload EQ curves to for room
| correction (such as different MiniDSP-branded correction
| boxes which are very popular) but I've gotten measurably best
| results (with my measurement mic) using old-school 31-band
| graphic equalizers that have the 31 physical fader sliders
| you move up and down. These old-school analog devices have
| lower latency in milliseconds than the hi-tech DSP stuff
| which needs extra time to buffer and process the signal in
| ram. The fanciest digital correction available in those AVR
| type devices (such as Dirac brand correction) delays the
| entire signal by as much as 100+ milliseconds (making gaming
| and live instruments impossible because the audio lags so far
| behind the event that produced the audio, like how thunder
| lags behind a lightning flash). The theory is that because a
| 20Hz frequency has a 50ms cycle-time, you need to delay the
| audio signal at least 50ms across the entire 16Hz-20KHz
| spectrum to "see" what you are correcting down near 20Hz.
| However, multiple blind listening studies have shown that the
| human ear is not time-latency sensitive to the lowest base
| frequencies. These frequencies are "felt" more than heard and
| the brain lags with letting you "feel" the deep rumble. Old-
| school analog equalizers only delay the actual low-
| frequencies that correction is applied to (the frequencies
| you actually slide up or down on the physical slider/fader
| controls). So if you slide the 50Hz fader then only that
| frequency has its timing altered, and the brain can
| definitely hear the loudness correction at 50Hz when Godzilla
| roars or the earthquake in your movie happens but it can't
| hear the timing difference if you delay the 50Hz wave
| slightly in order to correct its loudness. So you gain
| loudness accuracy (which you can easily hear) at the expense
| of timing accuracy (which at low frequencies you can't hear).
| Also, I'm really picky about speaker hiss and a good 31-band
| analog EQ introduces less noise/hiss than more expensive
| digital EQ boxes I've tested. I put my measurement mic right
| up to the tweater and recorded the hiss that the digital box
| made and took a screenshot of the spectrogram, then compared
| with my analog EQs and my analog EQs were better, noticeably
| enough that I didn't even need the mic in order to hear the
| hiss difference.
|
| So my advice is to get a UMIK-1 measurement mic and a 31-band
| graphic EQ, then download roomeqwizard.com software and learn
| to use it. It involves walking around your room with the mic
| while playing constant test tones and watching a sound
| spectrogram graph on your computer screen. Even though the
| test tone is constant, when you walk around your room with
| the mic you can see and hear how the tone changes due to the
| standing wave phenomenon. It will open your eyes (and ears)
| to how the room you are in affects the sound coming out of
| speakers. And rather than reading articles on the web you can
| actually experience for yourself the scientific reality of
| how it works, just like in high school chemistry class you
| see what happens with your own eyes when you mix vinegar with
| baking soda, rather than just reading theory in a book. The
| actual physical experimental confirmation is crucial.
|
| Adjusting anything over 250-500Hz is a waste of time because
| if you shift your head (or measurement mic) just a foot or
| two you get a completely different frequency response. When
| you test this yourself you won't need to take my word for it
| or read web articles shilling snake oil audio products. Your
| eyes and ears and calibrated measurement mic will confirm the
| scientific reality for you.
|
| As to other equipment... at the affordable lower end you want
| a USB or Thunderbolt interface with balanced XLR connectors
| connected either directly to studio monitors or to an
| equipment rack with the amps, crossovers, equalizers, etc
| needed to power big passive subwoofers. The Focusrite
| Scarlett 2i2 (~$160 on Amazon) is a best seller USB audio
| interface and crystal clear. I'm listening through one right
| now and I love it. Be aware that if using a Mac with a T2
| security chip (2016 and newer Macs) you need to use an
| external thunderbolt USB hub because T2 occasionally cuts out
| the internal USB; scroll down this article if curious:
|
| https://tidbits.com/2019/04/05/what-does-the-t2-chip-mean-
| fo...
|
| Here is a screenshot from the article of the T2 hiccup
| actually being recorded: you can see the audio waveform
| briefly cut out:
|
| https://tidbits.com/uploads/2019/04/T2-hiccup.jpg
|
| None of Apple's "fixes" fixed the problem. This was the last
| straw for me and many other audio guys so now we use both
| Ubuntu and Windows 10 with WSL instead of the Mac. Most
| photos of $1M+ recording studios I see nowaways have Windows
| 10 desktops. If you don't want Win10 telemetry spying on you
| you need to set up a pi-hole or external firewall box, but M1
| Macs and all iOS devices report your location and other
| telemetry to Apple now so you also need an external firewall
| for Apple now too, but I'm digressing from audio....
|
| Back to audio, the UMIK-1 USB measurement mic is usually ~$99
| new on Amazon/eBay/wherever. The roomeqwizard.com is free (as
| in gratis, not open source) Java software that can use the
| mic. For studio monitors, Yamaha and Adam Audio are both good
| and affordable. Many like the JBLs as long as you aren't too
| picky about hiss. Genelec is the very best and provably so by
| independent scientific measurement (see
| audiosciencereview.com measurements). But Genelec is stupid
| expensive, over $1k for a pair of their budget monitors.
| Anyway, this post is long enough and turning into an article.
| To summarize, get a Scarlett USB interface (~$160), the
| UMIK-1 ($99), a good pair of 5" or 7" studio monitors
| (Yamaha, Adam Audio, or maybe JBL, $300-$600 for the pair),
| and a graphic EQ. The bargain-basement Rockville REQ231 for
| ~$130 is essentially a cheap but good clone of a more
| expensive EQ. You can also spend $250-$400+ for Behringer or
| dbx/JBL which looks prettier in the rack but honestly doesn't
| sound any different.
| anotheryou wrote:
| I can recommend global EQs fixing your room in software.
|
| The most simple and imperfect route: get a global EQ for your OS
| and play around with a sine generator and notch filters. Fix the
| 1-2 frequencies where it's just way too loud.
|
| The fiddly and free route: https://www.roomeqwizard.com/ (search
| for tutorials on that) and than for windows there is "Equalizer
| APO" to load it. Use the best mic you have, in a really bad room
| even an sm57 will do wonders.
|
| The more expensive and easy route:
| https://www.sonarworks.com/reference with a measuring mic (they
| are not that expensive).
|
| I think the worse your room and speakers are the more this helps
| (I lived an a square tube, now in a better shaped room the effect
| is much less noticeable). For me it really cleans up the
| otherwise muddy lows. I can recommend boosting them afterwards
| for a more hi-fi sound, really neutral doesn't have the punch you
| might be used to :).
|
| Disclaimer: this will be worse than the perfect physical setup.
| You can fix some things in software, but there will be losses and
| it and only fix one point in your room really well. It's also a
| hassle to change EQ settings when you change to headphones.
| analog31 wrote:
| Quite agreed. Granted, measuring and testing things are things
| that I enjoy, but I can't even imagine debating the behavior of
| something like a speaker without doing some basic measurements.
| Not necessarily to correct anything, but at least to find out
| what's going on.
| MotherFunker wrote:
| I think many people don't realise is that 'ideally' (generous use
| of ideally) there is no front wall (the wall behind the speakers.
| This is why large recording studios have soffit mounted speakers,
| some experts actually encourage pushing the speakers closer to
| the wall to try and get as close as possible to approximate this.
| Obviously there is a lot more nuance in this - Always take
| measurements and use your ears too.
|
| As always, Hi-Fi and Studio set-ups/advice are not entirely
| inter-operable, and a lot of online chat can be both camps
| talking simultaneously which is difficult for a reader to parse.
| titzer wrote:
| Did you read the article? This is its basic conclusion.
| hatsunearu wrote:
| The real answer is: unless you have an anechoic chamber, you
| wanna have an EQ to tune out the room effects. It's not as
| expensive as you might think too.
| johnvanommen wrote:
| This article is unnecessarily complex, and offers solutions that
| are (mostly) applicable to older speakers.
|
| Most modern studio monitors put the tweeter in a waveguide. By
| doing that, it accomplishes two things:
|
| * The loudspeaker frequency response is consistent, no matter
| whether you're standing directly in front of the speaker, or to
| the sides. IE, the placement of the loudspeaker is less important
| than with older designs.
|
| * Most importantly, a waveguide takes the energy radiated by the
| driver and it focuses it into a narrower beam than a conventional
| tweeter. By doing this, reflections off of the sidewalls, ceiling
| and floor are less of an issue.
|
| To make a long story short, modern studio monitors with a
| waveguide are less fussy about placement.
|
| Reflections off of the sidewalls, ceilings and floor can still
| cause issues with lower midrange and midbass response, but these
| issues can be fixed with EQ to a large extent.
|
| The reason that EQ is less effective at high frequencies is
| because the wavelengths are so short. For instance, 5khz is 6.8cm
| long. Because it's so short, equalizing that frequency for one
| point in the room can screw it up at ANOTHER point in the room.
|
| Low frequencies are much longer, and because they're longer, EQ
| is more effective. For instance, 500Hz is 68cm long. Because of
| this long length, if you EQ a speaker to flatten out a peak at
| 500Hz, that EQ will be effective over a broad range of positions
| in the room.
| mannykannot wrote:
| The article is about low frequencies, and it is far from clear
| that putting tweeters in a waveguide avoids the issues raised
| in the article - in fact, just about everything you say that is
| applicable to low frequencies was covered in the article.
| moogleii wrote:
| > This article is unnecessarily complex, and offers solutions
| that are (mostly) applicable to older speakers.
|
| Wait, isn't the conclusion of the article to not overly worry
| about placement and just use your ears as a guide?
|
| The build-up is just background info, which I actually
| appreciated.
| titzer wrote:
| > Reflections off of the sidewalls, ceilings and floor can
| still cause issues with lower midrange and midbass response,
| but these issues can be fixed with EQ to a large extent.
|
| I don't really believe this. Ever put speakers in an empty,
| stone-walled, wood-floored room? No EQ in the world is going to
| fix that. You need acoustic treatment in some shape or form,
| unless your walls are made out of cotton.
| aidenn0 wrote:
| "to a large extent"
|
| A typical room with drywall, carpet (or rug) and upholstered
| furniture is going to be EQ'd pretty well. I suppose that
| could be considered "acoustic treatment" but most people just
| call that "normal"
| thisisbrians wrote:
| Having spent a bunch of time trying to figure this all out
| myself, as well, some practical tips (confirmed anecdotally by
| yours truly):
|
| - Place your speakers such that they form an equilateral
| triangle, with the tweeters pointing _directly_ at your head
| while you are seated in the control position. Near-field monitors
| are made for focusing on a 'sweet spot' like this. Using
| purpose-built speaker stands is the easiest route here.
|
| - Treat the first reflection points with foam, or anything that
| absorbs/scatters sound (e.g. I hung a huge shag rug on the back
| wall)
|
| - Break up smooth surfaces (walls/floors/windows) with other
| absorptive/non-smooth decorations and materials. Rug on floor,
| couch at back of room, curtains, even a bookcase; all will help
| absorb and scatter sound.
|
| - A good rule of thumb is to spend as much money on 'treating'
| the room as the speakers themselves (even great speakers will
| sound like trash in a room with no treatment).
|
| - When using the speakers for mixing/mastering work, listen at a
| conversational volume. The lower the volume, the less the room
| matters (and the room matters a lot).
|
| - You will get far better sound from decent headphones (I have
| HD650s) than from all but the most pristinely designed/tuned
| monitor setups. Probably would cost well over $10k and a lot of
| knowhow to beat the headphones.
| dharmab wrote:
| I noticed a huge improvement in the quality of my home office
| videoconferencing after pulling all my sleeping bags out of my
| camping gear and spreading them on the floor and hanging them
| around the room, just out of frame.
| 52-6F-62 wrote:
| I like the Tom Petty method--I'm interpreting here, and
| paraphrasing in my own format based on a longer discussion and
| probably mixing up some of this with other knowledge.
|
| Mix-- headphones
|
| Master-- monitors
|
| Test-- Toyota Corolla (Petty, said something like "just about
| everybody's gonna be listening in a Toyota"--they'd literally
| print a tape and run it out to someone's car)
| thisisbrians wrote:
| I laughed at the Toyota test, because there's a ton of truth
| in there. Got to test the mix on bad speakers to see if it
| translates...humbling, but necessary for a good mix. I do
| test in my car (coincidentally, it _is_ a Corolla) as well :)
| 52-6F-62 wrote:
| Isn't that the reason NS10's became popular as monitors,
| too? "If you can make it sound good on a pair of NS10's
| it'll sound good everywhere" being the mode+.
|
| It's definitely sage advice!
|
| + edit: Looks like I fell victim to hearsay. It's just
| something I'd heard so many times for so many years I
| assumed it was true, and it may be partly, but here's a
| great write up on the subject--tangential to the main
| thread: https://www.soundonsound.com/reviews/yamaha-
| ns10-story
| bsder wrote:
| Aprocyphally, this goes back to The Rolling Stones who used
| to keep a single car speaker on the mixing desk to
| approximate how it would sound on a transistor radio of the
| time.
| bhj wrote:
| It's not that your car system is good or bad, the point is
| that you are very familiar with how other productions sound
| on it, making it a good reference system.
| thisisbrians wrote:
| Yes and no. Your mix is never going to sound as crisp as
| it does in the studio (ideal listening conditions). Road
| noise + reverb off the glass + cheap speakers = not as
| good a listening environment. It's best to build
| familiarity of other commercial productions on your ideal
| setup (monitors/headphones/etc.) for referencing purposes
| earlier in the process, in my opinion. Good to reference
| on more 'everyday' listening systems, too (personal
| favorite, the iPhone speaker).
| aidenn0 wrote:
| Yet another reason to want 24V or 48V systems to displace
| 12V systems. The base-model car amp is going to always use
| the battery voltage, due to the noise, the max volume is
| going to be high, and that means 2Ohm (or lower) speakers
| built for maximum dB/W (so often no crossover) with a
| single +12V rail.
|
| I have a few rock CDs from the 90s ( _Dizzy up the Girl_ is
| one) that ar completely unlistenable in many cars; too bad
| Petty wasn 't involved in mastering those.
| [deleted]
| RedShift1 wrote:
| TLDR: Don't put your speakers between 1 and 4 m from your wall,
| orient your speakers to be directed at your ears.
| [deleted]
| tiniuclx wrote:
| There's a bit more to it that's been hinted at in this article.
| Briefly put, you don't want to be in the nodes of your room,
| the points where low frequencies bouncing off the walls cancel
| themselves out. For instance, no matter where you put the
| speakers, if they're in a cubical room [0] and your ears are in
| the centre of it, you'll hear very little bass.
|
| [0] Here's a simulation of where the modes of such a room might
| be:
| https://amcoustics.com/tools/amroc?l=300&w=300&h=300&r60=0.6
| hudo wrote:
| Please, please, please move your speakers away from the wall
| https://www.youtube.com/watch?v=9UA-VctzuFo
| claudiawerner wrote:
| To anyone else enjoying this video, this man, Steve Guttenberg,
| is a high-profile audio tech reviewer, and his reviews,
| "complete system recommendations" and musings on hi-fi are
| excellent. For many people, reviewers of hi-fi gear is the
| closest they can get to having an idea of what they're buying
| now that brick-and-mortar stores with listening rooms are
| harder to reach.
|
| I'd also recommend The British Audiophile's take on speaker
| placement and distancing:
| https://www.youtube.com/watch?v=VHOYXjVJKKY
| mrkeen wrote:
| This is a good start if you want to get into (or avoid)
| Guttenberg's stuff:
|
| https://www.youtube.com/watch?v=AfMg5P0_vJk
|
| Listen to him wax sarcastically about blind tests. Does he
| not get it? Or does he make his living from not getting it?
| claudiawerner wrote:
| I don't like everything he says, and I'm sometimes
| disappointed to see him refer to people who think Ethernet
| cables make no difference above $20 as "cable deniers"
| (though analogue cables can make a difference, especially
| interconnects) - but I don't think he's being dishonest, I
| think he's misinformed, and there's more than his "whatever
| works for you" takes on engineering matters. At least in my
| experience.
| genericacct wrote:
| This assumes everybody's hearing is the same but i guess it isn't
| and it also changes with age..
| tiniuclx wrote:
| This is a really important article if you want to get the most
| out of your speakers or studio monitors. When I was working on my
| home studio, I found that the position of the monitors had a huge
| impact on how they sounded.
|
| It took a good few days of moving the monitors & measuring the
| response, but I believe I was able to find a position that is
| usable & makes up for some of the deficiencies of my room.
| bartread wrote:
| Same goes for hifi to be honest. I didn't spend _that_ long
| fiddling with speaker position, because I just don 't have that
| many degrees of freedom in my living room without rearranging
| the whole room around the speakers[0], but after two or three
| hours spread over a couple of days or so I did get to what I
| think is the best compromise in terms of sound quality vs. the
| speakers being in the way. A few weeks later I added a
| subwoofer into the setup and, again, probably spent another 3
| or 4 hours spread over several days fiddling and listening to
| get that to sound the best I could at my typical listening
| volumes (what I wanted was to support the low end without
| overwhelming it).
|
| I haven't even got to the room that I use as an office/studio,
| which is a small spare bedroom. The room works well as an
| office now that I've redecorated it and put in new floor and
| shelves, but I need to finish off power routing and suchlike
| before I start on speaker placement.
|
| _[0] Many serious audiophiles would argue that you should do
| just this for the best results but I don 't have the space and
| I want a room that's usable for things other than just
| listening to music. I often think this is one of those
| situations where the perfect really can end up as the enemy of
| the good._
| archi42 wrote:
| Haha, I think your [0] is pretty much the common case for
| most who care for good sound. I had that setup once (35m2
| dorm room with a bed, a couch+small table, cloths rack and a
| desk - and two 1,40m/4.5ft speakers in the middle of the
| room). Yes: There is a VERY good point to arranging the room
| around the speakers. But that's difficult to explain to an SO
| who doesn't care for good sound and/or who prefers a more
| multi-functional living room.
|
| If you're listening alone, and don't care for a small sweet
| spot: In our study room I'm VERY happy using a DIY FAST/WAW
| system with a large full range speaker. The 4" FR (Tangband
| W4-2142) has some heavy beaming at higher frequencies. The
| sweet spot is rather small (I put it in front of my main
| display) - but reflections are a non-issue. The result is a
| very good sound stage. I implemented the cross over into a
| DSP (Beocreate Amp) and have one channel for each of the two
| drivers per side. But the only "real" correction I apply is
| at the low end (less room modes & extension to 40Hz at
| expense of ~9dB less SPL_max. Pretty nice for 4l encased
| volume and two 4" drivers).
| muxator wrote:
| > You know those mono-to-stereo mixing tricks that you're not
| "supposed" to do because of mono compatibility, but you end up
| doing all the time anyway? You know, like the one where you
| double the track, pan the two versions out and delay one side?
|
| Is there a name for this effect? I'd like to hear an example!
| stan_rogers wrote:
| I can't help you with a name, but it's one of the tricks that
| YouTube guitarist/instructor Paul Davids details in this video
| [0] - doubling down on it. (Basically he double-mics his
| guitar, sending each of the mics hard to one side, then again
| delayed and attenuated hard to the other side as well. What you
| get from that is a pretty good simulation of opposite-wall
| reflection from a larger space.)
|
| [0] https://www.youtube.com/watch?v=ww-cH29IGeM
| lmilcin wrote:
| Umm... it kinda seems the author actually got it wrong.
|
| Obviously, any information directed at people with no knowledge
| in area is simplified and possibly also intentionally incorrect.
|
| The simple articles on the internet and brochures assume you are
| stupid and you need safe way to set up your speakers. So that's
| why they ask you to place them far from wall. It would be stupid
| to try to explain physics of wave propagation and interference to
| people who need to read a leaflet to be able to set up their
| speakers.
|
| But if you have bit more knowledge it is not difficult to control
| your situation while also having speakers closer to the wall.
|
| Sound is distorted when you receive multiple waves that are out
| of phase and especially, as it usually happens, when different
| wavelengths are received at different phases (some in phase, some
| completely out of phase).
|
| While it is not possible to remove all reflections in a closed
| room (and some reflection is actually welcome because we want to
| feel being in a room rather than void) it is possible to make
| sure that the ratio of the wave from the speaker to the one from
| reflections is high enough that we do not perceive them as
| distortions.
|
| When a speaker is placed close to a wall, any energy radiated
| from the back of the speaker is reflected. There is also some
| energy from the front of the speaker, but because of the speaker
| itself only little of it reaches the wall behind and by the time
| it is reflected in the direction of the listener there is just
| not enough energy to be perceived as distortion.
|
| It is important that a lot of this is due to relative distances
| of sound sources (or reflections). If you sit 1m from the speaker
| that is 50cm from the wall, the sound from the speaker travels 1m
| but the reflection travels 2m to reach you. This means the
| reflection is attenuated by 6dB by distance alone (assuming
| omnidirectional emission from the speaker and that it is
| perfectly reflected from the wall).
|
| When a speaker is emitting very close to the wall and uses back
| port to emit bass, that back port is very close to the wall and
| not only gets distorted (due to being closer to the wall than
| wave length) but also reflected with a power very close to the
| original wave but out of phase, depending on frequency. That's
| what gives horrible result.
|
| Back ported speakers sound better because they elliminate sound
| of moving air, but they have disadvantage in placement close to
| walls. Just use front ported speakers when placing close to wall
| (see bookshelf speakers) which are designed exactly for that use
| case.
|
| More tips:
|
| - don't place speakers close to the wall if you are going to sit
| far from them, because this causes relative ratios to be close
|
| - it is ok to place front ported speakers close to the wall if
| you are going to sit close to them (for on your desk)
|
| - don't just focus on what's in front of you, if there is a wall
| behind you it is going to cause reflections that can cause
| powerful distortions if you are relatively close to it compared
| to the distance of speakers.
|
| - you can put something soft and permeable behind your speaker
| and behind your head to reduce high frequency distortions
|
| - you can play with some types of shapes around speakers and
| behind your head to reduce low frequency reflections distorting
| your sound. By having different parts of the reflection arrive at
| different times you reduce perceived effect of the distortion.
| kristo wrote:
| It seems like the bigger issue is the amplification of the
| standing waves in the room when the speaker is close to the
| wall, not the out of phase nature of the back and front sound.
| Could be wrong though.
|
| I also don't think placing objects around the speakers is going
| to help much with the main issue which is the low frequency is
| it?
| lmilcin wrote:
| Standing wave forms when significant part of the original
| energy is caught in a geometry that reinforces one wavelength
| and allows the wave to be reflected multiple times before
| being dissipated.
|
| For example, when you have two bare, parallel walls.
|
| Since you can't move the walls to not be parallel (although
| some people actually did it) what you can do is to look at
| other parts of requirements:
|
| -- ensure energy can be absorbed or dissipated before it can
| bounce multiple times
|
| -- ensure there are other objects that cause distances as
| seen by the wave to vary, this means there will be no single
| dominant wavelength that is going to be reinforced and if
| there is any standing wave it is going to be weak (will start
| with less energy and have much less of wall surface -- much
| smaller angle in which it can initially gather the energy).
|
| Absorbing bass is very difficult because, as mentioned by
| somebody else in another comment, it would require very thick
| material. And so the other way is to cause the energy to be
| reflected in various different direction so that it is not
| perceived as single sound.
|
| And so, putting objects in your room helps a lot as any
| person that has removed all their furniture from their room
| can attest.
|
| When you remove furniture the room acoustics suddenly becomes
| very noticeable due to powerful reflections and standing
| waves from bare, parallel, hard wall surfaces.
| the_other wrote:
| Your advice seems to match exactly what the article says,
| rather than opposing it. Can you explain the differences
| between your advice and the article's?
|
| (admittedly I read both quickly, with distractions, so I almost
| certainly missed something...)
| lmilcin wrote:
| The mistake the author made is saying the advice given in
| speaker manuals is wrong.
|
| Well, it is not necessarily wrong to omit a lot of complexity
| when explaining something to someone who is new (ie. speaker
| buyer who had to look at the leaflet). Even if the advice is
| not strictly correct, it is not wrong.
|
| We do this constantly, especially with children. We feed them
| with not strictly correct information because the
| alternatives are to not give them any, to give too much or to
| give information that is not useful.
|
| You would not tell your kids their uncle committed suicide by
| blowing his head off because he was unsatisfied with his
| miserable life because he made a bunch of lousy choices and
| because of this aunt left him for a younger guy which caused
| severe depression. That is way too much information for a
| child to handle.
|
| People who know better will know why the advice is structured
| this way and will know to ignore it.
|
| There is also incentive for producers to give information
| like that, because it is easier to require you to put your
| speakers far from any wall than to delve into particulars of
| your speaker placement. "We guarantee our product offers
| excellent quality if you put it far from walls, but should
| you decide to ignore that advice you are on your own"
| im3w1l wrote:
| Can't you put some material that will absorb rather than
| reflect behind the speaker?
| tiniuclx wrote:
| You can, but fundamentally the absorbent material needs to be
| as thick as one quarter of the wavelength of the frequency
| that you are trying to absorb. Deep bass, like e.g. 30Hz, has
| a wavelength of 8.6 metres. If you end up putting two metres
| of absorbent material on every wall, you don't have room for
| your studio anymore!
|
| This is why acoustic panels only work for mid-range
| frequencies and higher. Alternatively, you can also use bass
| traps with a membrane tuned to a specific frequency, which
| can attenuate said frequency without taking up ridiculous
| amounts of space.
| [deleted]
| lmilcin wrote:
| That's why you actually don't want deep bass in your
| speakers if you have tight constraints.
|
| It is better to have less deep bass (you can add more of it
| if you want) than have deep bass that is very distorted.
|
| Also, as I have added later after you posted, you can play
| with objects around your speakers to have the reflection
| broken and arrive at different time, effectively reducing
| its impact on the main wave. But as you pointed out that
| will only work for waves up to some length depending how
| large objects we are talking about.
| bombcar wrote:
| Isn't that why all these minispeaker systems (like you
| see for sale at Costco and Best Buy) all have a separate
| subwoofer and low pass filters on the speakers?
|
| Easier to place one subwoofer than to tune five speakers.
| lmilcin wrote:
| Partly.
|
| The are other reasons:
|
| - producing low end requires large speaker, and large ==
| costly
|
| - large speaker == lots of space required on desk,
| restricting your placement. Having small speakers on desk
| is a functional compromise. People working professionally
| with sound will buy studio monitors which take way more
| space but they can take it because sound quality is
| important because it is their job.
|
| - multiple speakers producing low end == timing and
| interference issues. When you have multiple speakers
| producing low end, you will hear interference as you move
| your head around as different lengths of waves cancel or
| reinforce at difference places.
|
| Since you don't need stereo for low end (your brain can't
| discern direction of very low end sound anyway) it is
| better to avoid that issue by having single speaker.
|
| Now, single speaker avoids those issues and allows you to
| be basically anywhere in the room and have acceptable
| sound, but adds discontinuity between your low and mid
| range. Audio professionals will prefer studio monitors
| because they care for for the sound to come undisturbed
| so much, they can place their speakers symetrically and
| keep their head at exactly right spot when listening.
| johnvanommen wrote:
| EXACTLY
|
| I see a lot of people putting up ugly "sound absorbing
| panels." What they don't realize is that it takes a LOT of
| material to absorb sound. 100Hz is over three METERS long.
|
| There are ways to reduce the impact of reflections, but
| sound absorbing panels are probably one of the least
| practical ways to do it.
| chaz6 wrote:
| The only thing that matters is what sounds best to you. You
| should place them where they sound best for your listening
| position. This is not a scientific process. It is a trial and
| error process.
| stinos wrote:
| Well, yes, but what this article tries to do is hint to where
| you can start your trial to reduce the number of error to begin
| with.
| dqpb wrote:
| For anyone else who is unfamiliar with "monitor" in this context,
| found this on Wikipedia:
|
| > Among audio engineers, the term monitor implies that the
| speaker is designed to produce relatively flat (linear) phase and
| frequency responses. In other words, it exhibits minimal emphasis
| or de-emphasis of particular frequencies, the loudspeaker gives
| an accurate reproduction of the tonal qualities of the source
| audio ("uncolored" or "transparent" are synonyms), and there will
| be no relative phase shift of particular frequencies--meaning no
| distortion in sound-stage perspective for stereo recordings.
|
| https://en.m.wikipedia.org/wiki/Studio_monitor
| benlivengood wrote:
| For people who have put significant effort into setting up a room
| with good acoustics and speakers; is the sound quality
| significantly better than good headphones?
|
| I can understand the other reasons speakers are nice; being able
| to hear other things besides the audio playback, sharing the
| sound with other people at the same time, etc.
| aldanor wrote:
| Depends on your definition of better. A lot of the time this
| will be done in a mixing room with studio monitors yielding as
| flat a response curve as possible (and without any room
| reverb). You will get a better sound in that it's precise, but
| it's not necessarily more pleasant to listen to.
|
| As for precision: it's easier to hear the panning / stage in
| good headphones just because it's so augmented. The low end -
| no matter how good the headphones are, you can't rely on them
| to mix it properly, you need good monitors. If you mix the low
| end on headphones, there's always a high probability that it
| will only sound good on this pair of headphones and not
| translate to other setups.
| hammock wrote:
| Headphones artificially increase the size of the stereo
| soundstage, that is one reason why it is preferred to mix audio
| on speakers
| lrem wrote:
| I'm not a musician, but got recently a pair of Presonus Eris
| 3.5 monitors as my desk speakers. I find that more pleasant to
| use than headphones I have (AT BPHS1 and Bose QC35).
| whiddershins wrote:
| This kind of down to earth advice with a medium amount of
| technical explanation is fantastic.
|
| One thing I would mention is that rigid fiberglass corner traps
| seemed to do a lot in my studio.
|
| Also if you are going to talk about room modes, you are also
| going to want to think about the permeability of your walls and
| whether they are going to even reflect the frequency in question
| and set up a mode.
|
| And also we may want to make a distinction between making a
| listening environment that sounds amazing, and one that has
| utility. It can be easy for an intermediate or beginner at mixing
| to get really tricked by a great listening environment in to
| doing things that won't translate.
|
| On the other hand, life is short, and listening to a beautiful
| set up is just a better quality of life if nothing else.
| stinos wrote:
| _you are also going to want to think about the permeability of
| your walls_
|
| If I understand things correctly, this was missing a bit from
| the whole (otherwise very good) explanation in the article: it
| constantly mentions 'walls' and each time I can't help but
| think that the difference between a solid concrete 30cm thick
| wall and a 10cm plasterboard plus some thermal insulation makes
| a difference in how it reflects lower frequencies. To the point
| that in the latter case there might be not much reflection at
| all and you actually have to start to measure from the wall (or
| whatever) in the next room?
| greedo wrote:
| Wood studs, drywall and fiberglass insulation don't do much
| to attenuate low frequencies. Fiberglass does almost nothing.
| Mass is the one thing that absorbs sound the best.
| cratermoon wrote:
| What if you're practicing with your high school rock band in
| an old wooden barn with boards that have become rock-hard
| after losing most of its moisture?
| anodyne33 wrote:
| This takes me back to working in a few (slowly going to way of
| the buffalo) "professional" or "big" studios. Both of the A
| studios I worked in had a big set of Genelecs in the bulkhead and
| two or three more mid and near field monitors just above or
| behind the console meter bridge.
|
| Each served it's own purpose and all the mixing guys I saw wound
| swap between them fairly regularly. In that situation it was
| about emulating different scenarios, from the 4" block speakers
| to get a feel for what someone would hear on an old car stereo to
| mid field Dynaudios that were more flat than hyped to get a feel
| for what the home audiophile might experience.
|
| That's not a practical approach for a small studio (either in
| size or budget) but having been out of that world for a long time
| it makes me wonder if someone would be better served with two or
| three pairs of reasonably priced pair of speakers rather than
| trying to perfect the sound of one pair that aren't going to
| reflect (no pun intended) other playback environments that aren't
| acoustically optimized.
| thisisbrians wrote:
| Astute. The goal isn't to get the mix sounding good on one
| particular listening system, but being able to hear the _raw,
| unadulterated_ signal as well as possible with knowledge of how
| it will or won 't translate in other environments. Always good
| to have multiple sets of speakers to test those assumptions out
| in real-time. Interestingly, even the geometry of your specific
| ears will color the resulting sound that is heard, which is why
| referencing to commercial tracks is so helpful in the process.
| sjcoles wrote:
| Hearing damage plays a role too I think.
|
| Aesop Rock is one that comes to mind where you can literally
| hear the hearing damage in the resulting mix. Late Zappa the
| same thing happened.
| kristo wrote:
| The main issue with speaker placement in a typical home recording
| studio is standing waves, and in this case placing speakers
| against the wall is going to amplify the problem, and no room EQ
| can fix it.
|
| Generally, you want your speakers to be a half wave length away
| from the wall for the first order standing wave in your space.
| This is so the wave output by the speaker will cancel with the
| wave resonating between your walls, which will help the issue
| quite a bit (though it's not perfect either).
|
| With something like the Klipschorn you're basically giving up on
| solving this issue with speaker placement and will have to resort
| to room modifications to ameliorate it. That said, you get a lot
| of benefits from the khorn also : )
| MrBuddyCasino wrote:
| There are different opinions regarding standing waves, at least
| regarding subwoofers. Some say they can actually be pleasant
| and beneficial, as they can boost perceived bass responses for
| smaller setups, depending on frequency and intensity.
| kristo wrote:
| Yea if you have one specific location where you listen to
| your music then you can certainly use the standing wave to
| your advantage, or even EQ the boosted response out at that
| frequency, but as soon as you move you will encounter
| problems.
|
| It's pretty remarkable to play a sine wave at the frequency
| of your room's standing wave and then just walk the length
| and hear it go from completely silent to very loud and back
| again. Makes you realize how much distortion this is actually
| causing
| MrBuddyCasino wrote:
| Yes, thus the ,,subwoofer crawl". I think in reality most
| people have 1-2 fixed locations in a room where they
| usually listen to music.
| S_A_P wrote:
| I'm always a bit flummoxed by guidelines like this being taken as
| gospel. Sure I will start with the manufacture recommended
| placement if my room allows, but at the end of the day _I_ have
| to hear the speakers so if it sounds good it is good rules for
| me. There really is no wrong if you like what you hear. Sure a
| rear port placed an inch from the wall will alter the response
| and likely cause chuffing as the air rushes in and out, but that
| falls under common sense to some degree. I guess one of the core
| tenets of "hifi" used to be flat frequency response from
| 20hz-20khz and no added coloration from the reproduction system.
| That's fine but often times today's music sounds crappy under
| those parameters. People like hyped bass and treble with a
| scooped midrange. That's okay. The parameters shift slightly when
| using studio monitoring to create a mix for music that needs to
| translate to other playback environments but even then a
| perfectly flat response is not necessary. If you know that your
| monitors are bass shy and increasing the bass will make it sound
| muddy on the majority of other systems then that is a data point
| you keep in mind. Learning the quirks of your monitoring setup is
| very important in this scenario. The point being that the
| guidelines are a starting point, not the rule.
| munificent wrote:
| _> at the end of the day I have to hear the speakers so if it
| sounds good it is good rules for me. There really is no wrong
| if you like what you hear. _
|
| There are two _very_ different goals that are easy to conflate
| and that the article isn 't very clear about:
|
| 1. If you are a music listener or music producer focusing on
| making music, you just want a room that _sounds great to you_.
| If you 're making music, you want a sound that inspires you and
| gets the creative juices flowing.
|
| 2. If you are a mixing or mastering engineer or a music
| producer focusing on polishing and mixing your work, you want a
| room that _gives you insight on how the audio will sound in a
| wide variety of listening environments._ Your goal is to get
| the song sounding as good on as many people 's speakers,
| headphones, and rooms as possible and your own personal setup
| is a proxy for that.
|
| For example, if you only have a couple of tiny speakers that
| don't go below 50 Hz, your song may have subbass that you
| literally cannot hear. But when someone with a subwoofer plays
| the song, all of that comes out. If it's too loud or out of
| tune, the song sounds like trash, but you have no way of
| knowing.
|
| So the goal is a monitor setup that is relatively neutral so
| that the song doesn't sound _better_ to you than it will to
| others. You want a fairly flat response so that you aren 't
| inadvertently EQ-ing the song to cancel out peaks and valleys
| in your room because then that will imbalance the sound in
| other rooms. And you want to cover the full frequency range so
| you can hear everything others will be able to hear. If the
| songs sounds great in your room, but it sounds like garbage for
| everyone _not_ in your room, it definitely is not great.
|
| Most articles about monitor placement tend to assume the goal
| is 2 more than 1. These days, the line is blurry because many
| musicians and producers are also doing a lot of the mixing.
| johnvanommen wrote:
| According to the research done by Harman/Samsung, listeners
| generally prefer a curve that's gently sloping by one decibel
| per octave.
|
| IE, if you want a pleasing sound, a loudspeaker that's playing
| 90dB at 100Hz should be playing 83dB at 16,800Hz. And the
| response curve should be consistent from point A to point B.
|
| This recommendation can be impacted by the power response of
| the speaker, but that's another subject...
| patrakov wrote:
| Well, the author could do more research.
|
| There are HiFi speakers that are designed to provide the correct
| frequency response when placed near a wall and sound wrong
| otherwise. "Klipschorn" would be an extreme example of this
| category.
|
| There are other speakers (actually the majority) that are not
| designed to be placed against a wall, but, if you use digital
| room correction features in your HiFi receiver, they still have
| to be placed against the wall, so that there is less work for the
| DSP to do.
|
| There are also so-called "electrostatic speakers" (e.g. "Quad ESL
| 2912") which absolutely must not be placed near the wall, because
| the rear wave is in counter-phase (unlike the traditional
| speakers), and will cancel the front wave exactly.
| tiniuclx wrote:
| There are some problems that cannot be corrected through room
| correction EQ, namely the Speaker Boundary Interference Effect,
| which happens when the reflection from a wall is out-of-phase
| with the signal that you want to hear, and produces a deep
| valley in the frequency response.
|
| You could try boosting at the frequency that the valley is at,
| but that makes both the signal _and the reflection_ equally as
| loud. Therefore, they cancel out in almost the same manner for
| basically no net gain.
| scns wrote:
| Bingo, they are called room modes:
|
| https://en.wikipedia.org/wiki/Room_modes?wprov=sfla1
|
| Their influence can be be diminshed with absorbers,
| construction of a room without parallel walls or so big that
| they can't be heard (eg Concert halls)
| claudiawerner wrote:
| >There are HiFi speakers that are designed to provide the
| correct frequency response when placed near a wall
|
| Another example may be the Ohm Walsh line of loudspeakers. I've
| only ever heard positive things about how close-to-life it
| sounds, and that's accomplished with the unique upward-facing
| driver and using walls and corners to an advantage.
| prox wrote:
| I know zero about this topic. Are there dynamic audio sensors
| that could provide real time adaptions to the room audio
| profile? Something like a light meter in photography?
| hwillis wrote:
| Only for the trivial cases. You could tell if the speaker is
| placed in a drastically bad place, ie it sounds bad
| everywhere, but you wouldn't be able to tell if the speaker
| sounds good where the listener is. For that you need to put a
| microphone (which itself would need to be of relatively good
| quality) where the listeners ears are.
|
| Even with measurements like that, it's pretty nontrivial to
| compensate for it. It's technically a proven problem[1]
| (solvable for some convex shapes) but its a little more
| complex than just adjusting the volume or phase of a given
| frequency. A room -and by extension all the little nooks and
| crannies of a room- acts as a resonator, and will gather and
| sustain notes. You need to counter that sustain ahead of
| time.
|
| 1: https://en.wikipedia.org/wiki/Hearing_the_shape_of_a_drum
| lozaning wrote:
| oh absolutely. http://accueq.onkyousa.com/
| eeZah7Ux wrote:
| I wonder why this is not more common.
|
| It should take a (cheap) microphone with a known response
| curve and a sine wave generator to calibrate any number of
| speakers in a room.
| drifkin wrote:
| Most midrange A/V receivers come with mics these days to
| do this sort of calibration. For example, Denon's version
| of this is called Audyssey http://manuals.denon.com/avrx4
| 100w/NA/EN/GFNFSYnuokgukf.php
| buildbot wrote:
| I believe apple homepods do this - " Direct and ambient audio
| beamforming Computational audio for real-time tuning"[1]
|
| [1] https://www.apple.com/homepod-2018/specs/
| johnvanommen wrote:
| Beamforming is a way of taking an array of drivers and
| manipulating their phase and frequency response to direct
| the sound in a calculated direction. IE, you can have seven
| drivers in a ring, and you can direct the sound in ONE
| direction instead of ALL directions.
|
| Amazon Alexa does the same thing, except with an array of
| microphones.
| buildbot wrote:
| Ah, I figured that would help with this issue as well but
| I can see it's a different thing now, thank you.
| mschulkind wrote:
| That's exactly what the digital room correction is that the
| comment you replied to mentioned, except it's not real-time,
| since the profile doesn't change rapidly. You push a button
| to run it every time you make major room changes like moving
| the speakers.
| prox wrote:
| Ah gotcha. Thanks!
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