soffit mounting speakers for mastering

[genericperson]

hello everyone,

i'm not sure if i picked the right subset of gearslutz, so my apologies if i'm in the wrong place for this.

i'm planning to build a listening/mixing/mastering room. i was thinking about pursuing a soffit mounted approach. does anybody have an opinion on this?

i plan to build a Tom Hidley-style, floated room within a room. with lots of trapping and broadband absorbtion. i'm into detail more than ambience, so this suits me.

somebody on the chatroom was saying that soffit-mounting is a waste of time unless you have a big room. but i can't see why that would make any difference.

i'm looking to do a 9.8x13.3 with a 7ft average ceiling, taking the slope into account (interior dimensions). i know this is kind of tiny, but it will adhere to the 1:1.4:1.9 ratio and i plan to do the best i can to control room modes with trapping, slot resonators, etc.

the reason i'm interested in sofft-mounting is that everything from the front comes at you time-aligned, rather than rear speaker radiation blending in out of phase, causing comb filter distortion and phase issues.

[Roland]

Originally posted by genericperson
hello everyone,

i'm not sure if i picked the right subset of gearslutz, so my apologies if i'm in the wrong place for this.

i'm planning to build a listening/mixing/mastering room. i was thinking about pursuing a soffit mounted approach. does anybody have an opinion on this?

i plan to build a Tom Hidley-style, floated room within a room. with lots of trapping and broadband absorbtion. i'm into detail more than ambience, so this suits me.

somebody on the chatroom was saying that soffit-mounting is a waste of time unless you have a big room. but i can't see why that would make any difference.

i'm looking to do a 9.8x13.3 with a 7ft average ceiling, taking the slope into account (interior dimensions). i know this is kind of tiny, but it will adhere to the 1:1.4:1.9 ratio and i plan to do the best i can to control room modes with trapping, slot resonators, etc.

the reason i'm interested in sofft-mounting is that everything from the front comes at you time-aligned, rather than rear speaker radiation blending in out of phase, causing comb filter distortion and phase issues.

Not true. Soffit mounting can and does introduce a lot of other issues into the equation. One of the reasons that many mastering studio's go with room positioned speakers.

Wherever you mount speakers you are going to get reflections, be it your floor, the ceiling, the console. Actually mounting speakers on stands can have the benefit of putting your speakers in "free" air making less early reflections. One of the principles that Thomas Hidley championed was the LEDE room that sought to do away with early reflections leaving only later reflections (15ms or more) which fall into what is known as the Haas effect. In brief the concept is that reflections of over 15ms are percieved by our brains as "ambience" and as such ignored from colouring the original sound.

For the size of room you are talking about you really are not going to be wanting to install huge monitors and most smaller monitors (if correctly designed) have the drivers placed at very specific points on the baffle to minimise cabinet defraction effects. Placing speakers like this into a soffit mount could (quite conceivably) place them way outside their designed parameters.

On a personal note, I rarely enjoy listening to "main" monitors partially because there usually are issues, maybe this is why in many major studio,s more often than not the engineers will end up using the nearfields.

Good luck with your build, whichever way you decide to go!


Regards



Roland

[genericperson]

wow, thanks Roland. i thought soffit-mounting would be a win-win. but it seems like it could be a win-lose (tradeoffs involved).

i have noticed many mastering guys (most?) using non-soffit mounted arrangements.

a few weeks ago i heard a floor-standing set of audiophile speakers that i fell in love with. i listened to tracks i know and respect, and the music sounded great. the balance was perfect. the sound was revealing without being harsh, the stereo image was gorgeous, and the speakers "dissolved" into the background. the bass was tight and punchy without being thin.

but i've been telling myself i will make mixing mistakes in a non-soffit situation due to time-align/diffraction issues.

but maybe i *can* give myself the green light on this setup afterall. what's more, these speakers were setup in a room very similar to the one i will be building in terms of shape, dimensions, furniture.

i'd love if a few more people in-the-know could chime in and tell me it's ok to do a non-soffit solution for critical listening/mastering.
i'm a chicken on this because i don't want to do it wrong.

[Bob Olhsson]

A real, current-design Hidley room sounds very good, although with a bit less extreme top-end than the very best mastering monitors. A "Hidley-style" room has generally been a recipe for disaster in virtually every example I've heard.

[oudplayer]

I also seem to remember there being issues with low-frequency response (which can be boosted by up to 6db), which some monitors compensate for with a switchable low-cut or low-shelving filter that's meant to be used when soffit mounted. In speaker designs lacking such a filter, you'd probably need to run the signal through a filter prior to the amplification, otherwise it's going to be boomy. Of the monitors we have in our studio (NHT A20/S20, Meyer HD1, Dynaudio BM15a, Genelec 1031a [but not for long...]), only the Genelecs are immediately usable in a soffited situation - the others recommend against it specifically.

Oh, and there's the problem with horning if your speakers are too close to the back wall in a soffit configuration. Thus, the sheer amount of real-estate you lose in a well-constructed soffit configuration may dissuade you from this approach...

[genericperson]

Thanks Oudplayer!

What do you mean by "horning"? that's a new one for me.

[dave-G]

I don't know who designed the room, but Emily Lazar's "The Lodge" mastering room in NYC seems to have a pair of soffited Dunlavy SM-1's up on the wall (thelodge.com). It might be worth a call or an email to see if she'd be willing to talk to you about what/how/why she did that. Otherwise, I can't think of any mastering suites based around soffited monitoring.

Not to say that proves anything in terms of the advisability of your idea. . . [shrug]

Good luck,
-dave

[Killahurts]

Originally posted by oudplayer
I also seem to remember there being issues with low-frequency response (which can be boosted by up to 6db), which some monitors compensate for with a switchable low-cut or low-shelving filter that's meant to be used when soffit mounted. In speaker designs lacking such a filter, you'd probably need to run the signal through a filter prior to the amplification, otherwise it's going to be boomy....

This is called half-massing by some. Some soffit speakers are mounted with the wall surface being made of hard material, like heavy plywood. In this case, the (omnidirectional) bass from the speaker is broken in half and reflects more bass energy out into the room. Oudplayer is right, the bass can be 6dB louder than freestanding. In my old studio, I had a pair of Tannoy system 12's that didn't sound right in the room unless they WERE mounted in the wall, but I think it was a fluke.

I've seen another studio that uses material-covered fiberglass boards around the speakers instead of a hard wall. The bass was flatter, but I didn't like the high end. It sounded kinda pinched.

In this studio, my ADAM's are freestanding, and I won't be going back to soffits. It's not as exciting as a well loaded wall, but it's much more accurate.

FWIW, Emily Lazar's room is the only well known ME I know of that has speakers in her wall.

[oudplayer]

Originally posted by genericperson
Thanks Oudplayer!

What do you mean by "horning"? that's a new one for me.

Not sure exactly what is mechanically happening, except that certain frequencies "horn" or spike out due to the back-of-speaker to wall-to-speaker-again refelction time. Basically, the opposite of "flat frequency response," where certain individual frequencies become really prominent. I think these are often low-mid frequencies and not so much high frequencies.

Others here probably know a lot more about what's actually going on - I've heard horning soffited speakers more often than not, and they can be devastating to a mix cos of the way you compensate for the errant frequencies!

[mcsnare]

Bernie Grundman Mastering and Glenn Meadow's room at Masterfonics? has always had soffit mounted speakers, but I agree it is much more difficult and expensive to build a room/monitor system that sounds great using this approach.

[Roland]

Originally posted by mcsnare
Bernie Grundman Mastering and Glenn Meadow's room at Masterfonics? has always had soffit mounted speakers, but I agree it is much more difficult and expensive to build a room/monitor system that sounds great using this approach.

Glenn's using PMC ALM1's these days. I read some quote on the board to the effect someone was saying that his soffit mounted monitors at Masterfonics were some of the best the poster had ever heard.

Regards


Roland

[Bob Olhsson]

The poster was Bob Katz who sat next to me on Glenn's couich!

[genericperson]

It's so strange how different ideas of "accurate" exist. Because at the Genelec info site, they talk at great lengths about how soffit mounting will more often produce better accuracy. They say a "fully spherical" system can be accurate, but seem to suggest a hemispherical setup (soffit mount) will typically produce superior accuracy on more rooms/systems.

In this studio, my ADAM's are freestanding, and I won't be going back to soffits. It's not as exciting as a well loaded wall, but it's much more accurate.

[/B]

[barefoot]

From a speaker designer's perspective soffit mounting is vastly superior to free standing.

GP you're right about early reflections and comb filtering being a major issue - especially in a small room where you can't pull the speakers far away from the walls. Check out my 2D Wall Bounce Calculator over at the Recording Studio Design Forum. It paints a rather bleak picture of the response anomalies associated with front and side wall reflections. Setting the distance of the monitors to the front wall to zero simulates soffit mounting. Since the calculator simulates free standing speakers you'll notice the +6dB bass response step that oudplayer mentioned.

Freestanding speakers have an issue called "baffle step" or "diffraction loss" which must be compensated for. Imagine the woofers and tweeters radiate omni directionally within their particular frequency bands. However they are mounted in the front baffle of a box. At high frequencies, where the wavelengths are small compared to the dimensions of the speaker baffle, the otherwise omni directional sound is forced to radiate only in the forward hemisphere. The sound that would have gone towards the rear of the speaker is added to the forward radiation, resulting a +6dB increase in output. However, at low frequencies where the wavelengths are large compared to the speaker baffle dimensions, the sound radiates omni directionally. So there is a 6dB mismatch in the on-axis response between the low end and the high end of the spectrum.

Freestanding speakers compensate for this mismatch with a -6dB high shelf filter (typically this is designed into the crossover) to flatten the on-axis response. That's fine, but you wind up with a power response mismatch. In order to get a flat on-axis response the total power emanating into the room must be +6dB higher in the bass. Now, when you take a free standing speaker and flush mount it, you force ALL wavelengths to radiate in the forward hemisphere. This results once again in a 6dB response mismatch, only this time it's heavy in the bass.

This mismatch can be compensated for with a specifically designed low shelf filter. I have posted a design for a DIY Baffle Step Decompensation Filter over at the Recording Studio Design Forum.

All in all, soffit mounting yields markedly superior results. It avoids many problems with wall reflections, comb filtering and edge diffraction. Additionally, both the on-axis and power responses are flat.

Hope this helps!

Thomas

[thethrillfactor]

Originally posted by barefoot
From a speaker designer's perspective soffit mounting is vastly superior to free standing.

GP you're right about early reflections and comb filtering being a major issue - especially in a small room where you can't pull the speakers far away from the walls. Check out my 2D Wall Bounce Calculator over at the Recording Studio Design Forum. It paints a rather bleak picture of the response anomalies associated with front and side wall reflections. Setting the distance of the monitors to the front wall to zero simulates soffit mounting. Since the calculator simulates free standing speakers you'll notice the +6dB bass response step that oudplayer mentioned.

Freestanding speakers have an issue called "baffle step" or "diffraction loss" which must be compensated for. Imagine the woofers and tweeters radiate omni directionally within their particular frequency bands. However they are mounted in the front baffle of a box. At high frequencies, where the wavelengths are small compared to the dimensions of the speaker baffle, the otherwise omni directional sound is forced to radiate only in the forward hemisphere. The sound that would have gone towards the rear of the speaker is added to the forward radiation, resulting a +6dB increase in output. However, at low frequencies where the wavelengths are large compared to the speaker baffle dimensions, the sound radiates omni directionally. So there is a 6dB mismatch in the on-axis response between the low end and the high end of the spectrum.

Freestanding speakers compensate for this mismatch with a -6dB high shelf filter (typically this is designed into the crossover) to flatten the on-axis response. That's fine, but you wind up with a power response mismatch. In order to get a flat on-axis response the total power emanating into the room must be +6dB higher in the bass. Now, when you take a free standing speaker and flush mount it, you force ALL wavelengths to radiate in the forward hemisphere. This results once again in a 6dB response mismatch, only this time it's heavy in the bass.

This mismatch can be compensated for with a specifically designed low shelf filter. I have posted a design for a DIY Baffle Step Decompensation Filter over at the Recording Studio Design Forum.

All in all, soffit mounting yields markedly superior results. It avoids many problems with wall reflections, comb filtering and edge diffraction. Additionally, both the on-axis and power responses are flat.

Hope this helps!

Thomas

Not all speakers are created equal.

These free standing speakers deal with the problems of early reflections the best that i've heard:

http://www.gradient.fi/En/Products/Revo/Revo1.htm

They are pretty flat sounding, but don't sound boring.grudge

[thethrillfactor]

Originally posted by dave-G
I don't know who designed the room, but Emily Lazar's "The Lodge" mastering room in NYC seems to have a pair of soffited Dunlavy SM-1's up on the wall (thelodge.com). It might be worth a call or an email to see if she'd be willing to talk to you about what/how/why she did that. Otherwise, I can't think of any mastering suites based around soffited monitoring.

Not to say that proves anything in terms of the advisability of your idea. . . [shrug]

Good luck,
-dave

Those aren't Dunlavy's but the older Duntech's PCL-5's which orignally were wall mounted speakers(early 80's).

Its a different sound than the SM1's(which i personally use).

She mostly uses her Genelecs 1031's though for most of her mastering duties.

[dave-G]

Originally posted by thethrillfactor
Those aren't Dunlavy's but the older Duntech's PCL-5's which orignally were wall mounted speakers(early 80's).

Its a different sound than the SM1's(which i personally use).

Aha!! Well, from the pics, it was hard to tell. Interestingly, I've got a pair of SM1s around here too. . . I don't use them every day, but they are good.

She mostly uses her Genelecs 1031's though for most of her mastering duties.

-dave

[NathanEldred]

Well, it shows too.

[thethrillfactor]

Originally posted by dave-G
Aha!! Well, from the pics, it was hard to tell. Interestingly, I've got a pair of SM1s around here too. . . I don't use them every day, but they are good.


-dave

Dave,

Its all in the amps for Dunlavy's.

They are always picky and the SM1's are no exception.

Hey at least she is cute in person.

Just kidding, she is not only cute but she has some ideas on what she is trying to do. I've had conversations with her on her choice of 1031's and that's what she likes.

Who are we to judge?

Hey she is getting tons of work here in the city, where other people are just trying to get by.

[barefoot]

Originally posted by thethrillfactor
Not all speakers are created equal.
These free standing speakers deal with the problems of early reflections the best that i've heard:
http://www.gradient.fi/En/Products/Revo/Revo1.htm
They are pretty flat sounding, but don't sound boring.

The figure-8 radiation pattern of a dipole can help with side wall reflections, but not with front wall reflections. And if you download my wall bounce calculator, you'll see that front and side wall reflections cause response ripples well above 1kHz for a 43cm wide cabinet. These dipole woofers only go up to 200Hz. So these speakers deal with about 3 octaves of midbass and midrange response no better than a normal enclosed speaker. Finally, dipoles have a natural 6dB/octave bass response drop due to front/rear wave cancellation. This requires a low pass compensation filter to flatten the response. Which means very high power consumption and extremely large driver excursions. The net result is lower sensitivity and higher bass distortion.

I've never heard these speakers, and they might be good products, but they certainly have their tradeoffs.

No matter how you cut it, soffit mounting results in the fewest compromises.

Thomas

[Brad Blackwood]

Originally posted by barefoot
The figure-8 radiation pattern of a dipole can help with side wall reflections, but not with front wall reflections. And if you download my wall bounce calculator, you'll see that front and side wall reflections cause response ripples well above 1kHz for a 43cm wide cabinet. These dipole woofers only go up to 200Hz. So these speakers deal with about 3 octaves of midbass and midrange response no better than a normal enclosed speaker. Finally, dipoles have a natural 6dB/octave bass response drop due to front/rear wave cancellation. This requires a low pass compensation filter to flatten the response. Which means very high power consumption and extremely large driver excursions. The net result is lower sensitivity and higher bass distortion.

Yeah, the tech stuff is nice, but how do they SOUND?

No matter how you cut it, soffit mounting results in the fewest compromises.

I know you make soffit mounted speakers, so it's understandable that you feel that way, but don't you think if it were that cut-n-dried that:
1] You'd see more mastering rooms using soffit mounted speakers, and
2] There would be more than a handful of speaker builders selling them?

Rhetorical questions, mind you. We've been through this before, and the best sounding rooms I have ever heard (and I've heard very many) were utilzing free standing monitors, with possibly one exception (GM's old room)...

[barefoot]

Originally posted by Brad Blackwood
Yeah, the tech stuff is nice, but how do they SOUND?

Personally I try to use that "tech stuff" to create speakers that SOUND as much like the source material as possible.

I know you make soffit mounted speakers, so it's understandable that you feel that way, but don't you think if it were that cut-n-dried that:
1] You'd see more mastering rooms using soffit mounted speakers, and
2] There would be more than a handful of speaker builders selling them?

Rhetorical questions, mind you. We've been through this before, and the best sounding rooms I have ever heard (and I've heard very many) were utilzing free standing monitors, with possibly one exception (GM's old room)...

Actually my speakers are designed to work either way. But I do think, if possible, soffit mounting is preferable. This is especially true in small rooms where early reflections are an even bigger concern.

The reason I think many people prefer the basic sound of freestanding speaker implimentaions is because soffit mounts have a flat power response. Like I explained earlier, freestanding speakers necessarily have a "hyped" bass power response in order flatten out the on-axis (anechoic) response. Many people (myself included) prefer this hyped bass response. In fact, one could reasonably argue that the freestanding power response is more "correct" because most consumer speakers are freestanding. Even so, soffit mounting is still superior. The room response can be tailored to provide the desired "correct" ambient (power) response. And the soffit mount still has the advantage of the ability to create an early reflection free zone - avoiding comb filter ripples. So, with soffit mounting you can still have the power response you want while gaining a more accurate and detailed midbass-midrange response.

So, I'm not completely disagreeing with the conventional wisdom. I'm saying, if properly implemented with the room reponse, soffit mounting can provide superior results - without sacrificing the overall "SOUND" of freestanding speakers.

Thomas

[barefoot]

I forgot to mention that tailoring a soffited room response for a freestanding "sound" is fairly straightforward. It requires less bass absorption relative to the high frequency absorption. This actually makes life a little easier because bass is harder to absorb. But, as with all things, there is a tradeoff. Less bass absorption means a greater potential for standing waves. Therefore, the room geometry becomes more critical. Splaying the walls and angling the ceiling is definitely the way to go. Of course, this is the way to go with any world class room. And it's also necessary for minimizing early reflections, so it really shouldn't be an extra burden.

Thomas

[Brad Blackwood]

My point isn't which is technically better, but to point out that those who can build ANYTHING they want in their rooms use free-standers 99% of the time. In fact, the only guys that use soffit-mounted mastering monitors (that I'm aware of) are old school guys that learned to cut records before good free-standers were available...

[barefoot]

I hear what you're saying, but I AM trying to point out what is what is technically and sonically better. Just because there's a "best known method", doesn't mean it can't be improved upon. And I think there is a very good reason why freestanders dominate. In my opinion, the majority of great speaker design innovations over the past decade or so have come from hi-fi manufacturers (certainly B&W is on the top of that list). And of course, the consumer market dictates freestanding speakers. So, MEs looking for the very best sounding speakers are naturally going to gravitate towards these products.

In this case, however, some of the baby was thrown out with the bathwater. Old school monitors are out and the new school is in. The new school by virtue of their heritage happen to be freestanding, so soffit mounting must not sound as good... right? Well, I'm saying "not right". Yes, the newer generation of hi-fi type monitors sound much better than the old style soffited monitors, but this doesn't mean that soffits were the problem. The pro speaker designs themselves were the problem (and in many cases still are).

Thomas