In-wall Speaker Measurements (Monoprice THX-365IW)

[Nathan Raymond]

In-wall or “soffit-mount” installation is something I‘ve seen in older recording and mastering studios but I’ve never had any personal experience with it. I’m following closely because a new house on the horizon brings such an approach into feasibility.

BT has some pretty serious in-wall speakers in his home studio. Skip to 22:21 to see them:

https://www.facebook.com/video.php?v=499216134270877

 

[YSC]

Great stuff, but you know asking for advise on purchase new system (toy) from us will always result in a big YES right? (Especially it’s not our money for most part)

 

[Helicopter]

This is excellent Amir. I am a huge fan of this category and am highly anticipating some more Revels, some Focals, and some.JBLs... maybe a couple others.

Seems like there should be a simple way to replace only part of the baffle so you don't have to re build the thing every time.

 

[Chromatischism]

The new measurement system gives us a much more close to real life results. The cost is an afternoon to build a precision baffle for every in-wall speaker to measure and thousands of dollars in software licensing. I am game

Lol...no rest for the wicked, huh.

Nice work.

 

[hex168]

Just thinking out loud: can your baffle also be used to measure on-wall speakers?

 

[MatthewS]

I’d love to see more in-wall measurements. I have Revel W553L in my listening room and quite enjoy them. Some day I’ll redo all the walls and run surround sound with in-wall speakers and subs and it would be great to have more data.

 

[amirm]

Seems like there should be a simple way to replace only part of the baffle so you don't have to re build the thing every time.

I am hoping that some are similar sized so after I build half a dozen of them, I can reuse them. Won't know until I get into it more.

 

[amirm]

Just thinking out loud: can your baffle also be used to measure on-wall speakers?

You are thinking like I am. I am going to try it.

 

[respice finem]

Looks very promising. Just a thought, inspired by looking at the 10kHz difference with grille on / off: Would it make sense to "soften" the baffle (e.g. with felt) to eliminate remaining treble reflexions, or is the software's time window short enough to "calculate it away"?

 

[ROOSKIE]

This is great work, thanks Amir. And rather unique info as I don't see ANYone else publishing good data for in walls. Arguably even more important to have data like this for in walls vs box speakers as once you cut your walls and install them, your stuck with em. Can't demo like box speakers. And there are not only aesthetic advantages, but potentially big sonic advantages as well assuming the wall cavity construction doesn't cause major issues. I mean, holy cow, the horizontal dispersion is unbelievable! Talk about hearing the same thing no matter where you sit……..at least for most of the frequencies that cover almost all music i.e. below 7KHz. And no SBIR. So many wins.

Aside from a very few, that's not really the same as these in-wall types. Those are just normal boxes in soffits. But yes, they are good, if the speakers are appropriate (must be either sealed or front ported). They essentially entirely eliminate SBIR which simplifies acoustics in the room a lot.

Howdy, why would this eliminate SBIR?
As I understand it the front wall (or installed wall if not a L-C-R)reflection is eliminated. The rest of the reflections, side walls, ceiling, floor reflection to drive units, floor bounce, back wall and the myriad other bounces back and forth are not eliminated. (although the "myriad" ones essentially average out)Plus if you have large surfaces and objects such as a large table or other massive thing - the SBIR is in full effect.
The other downside is the massive baffle which is proposed to deeply effect the imaging.

 

[ROOSKIE]

This makes me wonder if in-wall speakers have an inherent advantage in terms of directivity, enclosure resonances, etc

Well, this one has very wide horizontal response. I actually don't think I would like that. As background music yes. That wide spread would be great. I am noticing I like a more controlled directivity for listening in the sweet spot which is how I usually listen. Who knows though - I'd love to listen to a few in walls installed in a HiFi type set-up.
I wonder @amirm if you are going to listen. I would be curious how they sound. Might be hard unless you are going for the open baffle effect.
Maybe at some point in the future you could devise a way to mount them in a "window" (plywood window) vented to the outdoors of the garage. make a sort of in wall listening room. Obviously a huge commitment thought.

 

[redshift]

Why in-wall, when you can go on-wall for the practicality of moving and measuring the speaker before you bolt it on the wall?

(Shameless Carlsson plug coming)

FR in the listening position (no EQ):

Details explained in:
https://www-carlssonkult-se.transla...x_tr_tl=en&_x_tr_hl=sv&_x_tr_pto=ajax,nv,elem

Stig Carlsson’s ‘ortho acoustic’ speaker design principles has a (well deserved?) cult status in Sweden.

I haven’t seen (much) measurements and listening reviews on ASR of unconventional speaker designs, as in ‘not-a-box-on-the-floor-some-distance-from-the-walls’.

 

[MatthewS]

Howdy, why would this eliminate SBIR?
As I understand it the front wall (or installed wall if not a L-C-R)reflection is eliminated. The rest of the reflections, side walls, ceiling, floor reflection to drive units, floor bounce, back wall and the myriad other bounces back and forth are not eliminated.

http://arqen.com/acoustics-101/speaker-placement-boundary-interference/

http://tripp.com.au/sbir.htm

The wall behind your speaker is the most offensive.

If your back wall is 10 feet away the quarter wavelength is below 30hz. Most speakers aren’t playing that low.

 

[ROOSKIE]

http://arqen.com/acoustics-101/speaker-placement-boundary-interference/

http://tripp.com.au/sbir.htm

The wall behind your speaker is the most offensive.

If your back wall is 10 feet away the quarter wavelength is below 30hz. Most speakers aren’t playing that low.

Howdy, I have read those sites previously and often use the calculator when need be. In fact that calculator deff shows the impact of cancelations due to floor and side walls.
The floor and side walls and typically ceiling(although often less do to the likely further distances of the drivers to the ceiling surfaces) have quite an impact both in what I have read and what I have measured as I position speakers in my room.
I guess I just not sure why so often I see people claiming an absence or elimination of SBIR with in walls. Certainly not having the reflection from the host wall is amazing but not really an elimination of the issues.
What am I missing here?
Interesting dipole speakers want that front wall reflection badly in order to give that particular dipole sound, that is for another day though and really a totally different thing.

 

[MatthewS]

What am I missing here?

Probably simply that most folks use it as shorthand for the front wall reflections.

 

[bigjacko]

Since no one has answered why the directivity is so wide and probably will ignore my question since I am not famous here, I will try to answer it now and hopefully get it started. The directivity depends on the diameter of driver and wave length of frequency. When frequency got to a point the direcitivty will become narrow, but it does not suddenly become narrow, it will happen gradually.

For frequency that radiate more than 2 pi radian or 180 degree the sound will bounce off the baffle. For normal speakers with box there are also bounce off, but the amount is not much because the baffle is small. For in wall speaker the amount is more because the whole wall is baffle, in this case the board made by Amir.

Few things I don't know are (1) is there directivity for bounces off, (2) how much bounce off in a certain length of baffle or it will be continuous and (3) is it bounce off or more like crawling along and probably has different directivity to driver's directivity.

 

[Chromatischism]

Probably simply that most folks use it as shorthand for the rear wall reflections.

Front

 

[DSJR]

BT has some pretty serious in-wall speakers in his home studio. Skip to 22:21 to see them:

https://www.facebook.com/video.php?v=499216134270877

Ah, my favourite speaker brand

I'll get me coat...

 

[abdo123]

the ultrawide dispersion is only +/-90, not +/-180 like other speakers. so it's not really that wide, just much much more uniform and controlled.

speakers with finite baffles produce low frequencies omni-directionally, speakers with infinite baffles (in-walls) forward fire all frequencies till beaming occurs.

Also no cabinet and ports means no cabinet and port resonances.

 

[abdo123]

Why in-wall, when you can go on-wall for the practicality of moving and measuring the speaker before you bolt it on the wall?

(Shameless Carlsson plug coming)
View attachment 141739

FR in the listening position (no EQ):
View attachment 141741

Details explained in:
https://www-carlssonkult-se.transla...x_tr_tl=en&_x_tr_hl=sv&_x_tr_pto=ajax,nv,elem

Stig Carlsson’s ‘ortho acoustic’ speaker design principles has a (well deserved?) cult status in Sweden.

I haven’t seen (much) measurements and listening reviews on ASR of unconventional speaker designs, as in ‘not-a-box-on-the-floor-some-distance-from-the-walls’.

how many human kidneys are those speakers worth?