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

[q3cpma]

Interesting Amazon review I encountered: https://www.amazon.com/Monolith-THX-365IW-Certified-Neodymium-Shorting/dp/B07YLZ3R4T#customerReviews

 

[testp]

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.

will the woofers perform the same and sound great, if volume inside the walls are different for L & R, or would it be better if the speakers have boxes inside the walls as well..

 

[testp]

also a subwoofer at the wall, vs facing the wall would be intresting. at my place it made a big diference

yes, a better way is to build a house as a subwoofer, kick ass , but neighbours would look akwardly...

 

[testp]

They don't eliminate SBIR.

SBIR improvment is one half of the advantage however. You effectively halve the mess since you are only radiating into a half space. Since the worst of the mess comes from the nearby surfaces removing the rear wall is a big win. Once you get to second reflections you are already well ahead of the game, and the mess remains devoid of the strong effects due to the first reflections.

The second win is removing baffle diffraction effects. No more baffle step compensation, and the mid range is no longer controlled by proximity to the edge of the cabinet. We tend to be oblivious to this part of the equation. The reason the speaker measured here has such a wide directivity well into the upper mids is simply that there isn't a baffle edge reflecting the energy back. What you see is the natural directivity and response of the driver. Choice of crossover points remains important but is directed more by the driver diameter and capability than the baffle design.

In ordinary cabinet speakers the designer is always compromising things in order to get a useful response in the face of the cabinet effects. You don't see this in any obvious place, as it gets folded into the overall driver response, but it is sitting there under the surface and is responsible for a whole host of second order ripples and artefacts.

Clearly the design response needs to take account of the different mounting, as the final at-listener response still needs to be level and smooth. But this becomes easier.



Drywall and other walling materials are usually fairly well damped. You don't notice them resonating in a room with box speakers driving the room, yet the energy hitting the walls is similar, just more spread out. Indeed drywall is a good starting point for a dead walling material.

Box resonances don't need to be any bigger problem than any other sort of box. The dimensions are a bit odd, and so the frequencies that resonances might appear at are different, but other than that, nothing special. The very shallow depth tunes the F-R resonance out of the passband of a woofer. If you have a 2-way you might have a bit more to contend with, but some appropriate absorption will help. IMHO such resonances are often unappreciated in importance, but they are not insurmountable. If you see peaks at about 800Hz you might guess where they came from.

yes, but we would need Amirm objective listening as well, comparing to something, i would not consider in-walls without it..

 

[ROOSKIE]

Interesting Amazon review I encountered: https://www.amazon.com/Monolith-THX-365IW-Certified-Neodymium-Shorting/dp/B07YLZ3R4T#customerReviews

Hmmm, well curious why that person is eq-ing for flat in-room.
10+db boosts?
Multiple blown tweeters.
Might be something defective about this cats measurements and approach.
What are the odds their amp can even drive those boosts cleanly if the baseline is already loud.
Could be frying those tweets.
Not saying the speakers are not defective but based on what I am seeing user error is also worth looking into.

 

[Rick Sykora]

Question is rather: is there demand for reviews of in wall speakers? When it's considerably more effort than measuring normal speakers while the ratio of people actually buying and installing them is one to hundred I don't think it's worth going that lenghts. Unless of course you're having fun Amir and it's a subject you'd like to research.

Yes. kind of what I meant to post originally. There are a few segments to consider here.. Am guessing most current members do not use or use for secondary purposes (surrounds, etc.). So, probably less interested in built-ins, but seems like a poll would address interest by this segment.

A potential ASR growth segment might be for home theater. If there are as many installed as some claim, Amir testing could be useful for them. I suggest this segment might be further divided into audio professionals, building contractors and more casual users. All could benefit from having a place to get consistent speaker performance comparisons. However, this all is predicated on how the test speakers will be obtained. If the current state is any indication, manufacturers may not be all that interested in measurements. Unless @amirm has a different plan for test unit acquisition, expect the samples will be limited as they are today.

Unless the current operating model of ASR changes, it is better to be targeted more specifically rather than be spread out so thin that you get a compromise forum that satisfies nobody.

 

[dasdoing]

yes, a better way is to build a house as a subwoofer, kick ass , but neighbours would look akwardly...

not realy needed. here there isn't realy SBIR left when facing the wall: https://www.audiosciencereview.com/...th-subwoofer-options.17066/page-4#post-625819

note that the meassurement has NO SMOOTHING

 

[Tom C]

I’m hoping Atmos will continue to gain traction, and in ceiling seems like the best solution for the height channels. The WAF is the very highest, and the cost is minimized. So these types of measurements then become very important.
The downsides to in-ceiling installation were the mess I made cutting into the drywall (the dust was so fine, we never got it out of the wood floors), and the fact that when a job change forced a move, I had to leave the speakers behind.

 

[dasdoing]

hoping Atmos will continue to gain traction...........................I had to leave the speakers behind.

I can imagine that at some point homes would be sold/rented including an atmos system. "atmos-house for sale"

 

[sam_adams]

Not trying to be anal or make a mountain out of a mole hill but since speaker boundary interfence responce is deff not at all only an effect of only the front/host wall I wish for the sake of the many casual readers that somehow that was clear. Using terms like eliminate, give the wrong idea about the situation - help mitigate, remove host wall effect, no front wall SBIR effect, ect could work as shorthand as well as being accurate.
The speaker has several major boundary interference reflections.
Anyway I will drop it, just hoping folks get what I am saying.
I suppose it is kind of like how "distortion" somehow became short for harmonic distortion even though there are many, many types of distortions in sound reproduction.

While I likely won't be doing in walls anytime soon. Really interested in if I would like the sound of in walls. They would be a relative snap to DIY.

If you're having trouble now understanding SBIR, just wait until you try to wrap your head around the Allison Effect.

 

[redshift]

If you're having trouble now understanding SBIR, just wait until you try to wrap your head around the Allison Effect.

I think Stig Carlsson implements a flow restriction/internal resistance for the (mid) woofers in some of his speakers, such as the OA 51/61.

If I understand this effect it correctly it is an “acoustic” impedance mismatch between the speaker and room. Someone correct me if I’m mistaken.

The speaker puts in LF power into the room, it bounces and then reaches the speaker (imagine it as a point source) as constructive or destructive interference.

If the interference is destructive, it “sucks” out the bass, with constructive it gets “boomy”

Maybe, perhaps, remember; don't take my amateurish guesses in audio seriously.

 

[Chromatischism]

Drywall and other walling materials are usually fairly well damped. You don't notice them resonating in a room with box speakers driving the room

I do...

 

[Chromatischism]

The bass and upper bass will be superb due to the in-wall mounting.

I'm most interested in knowing if there are differences in clarity and imaging. Mainly if there are any detrimental effects.

 

[redshift]

The bass and upper bass will be superb due to the in-wall mounting.

I'm most interested in knowing if there are differences in clarity and imaging. Mainly if there are any detrimental effects.

I think you need damping material around the speaker on the wall. It has been discussed earlier in this thread. Have a look at the OA 61 wall-mount “elephants ear” to combat this distortion.

 

[levimax]

I think you need damping material around the speaker on the wall. It has been discussed earlier in this thread. Have a look at the OA 61 wall-mount “elephants ear” to combat this distortion.

View attachment 141853

These are nice but they are not in-wall mounted so they really don't have anything to do with in-wall mounted speakers.

 

[MaxRockbin]

Wouldn't the size of the wall cavity have a significant impact on performance - just as the size of the box impacts the performance of regular box speakers? Wouldn't insulation in the wall have a significant effect too?

And, as Chromatischism said, drywall or lathe & plaster will vibrate with bass, a lot more, I think, than the braced MDF of a regular speaker enclosure. Won't that be an issue?

 

[redshift]

These are nice but they are not in-wall mounted so they really don't have anything to do with in-wall mounted speakers.

Yes they do, since the tweeter and mid-bass is near the rear wall and directed upwards. Why do you think there is a damping panel there?

 

[redshift]

Wouldn't the size of the wall cavity have a significant impact on performance - just as the size of the box impacts the performance of regular box speakers? Wouldn't insulation in the wall have a significant effect too?

And, as Chromatischism said, drywall or lathe & plaster will vibrate with bass, a lot more, I think, than the braced MDF of a regular speaker enclosure. Won't that be an issue?

Add some beefy weight to the speaker’s back. Some old plates from the gym would be fine to make the resonance with the wall basically zero. I doubt some 20kg + speaker would make it move much as it pounds energy into the room.

Smallish bookshelves 5kg won’t move much, right? Why should a wall+speaker move?

 

[MaxRockbin]

Add some beefy weight to the speaker’s back. Some old plates from the gym would be fine to make the resonance with the wall basically zero. I doubt some 20kg + speaker would make it move much as it pounds energy into the room.

Smallish bookshelves 5kg won’t move much, right? Why should a wall+speaker move?

It's not about the motion of the speaker, but the motion of the air. Why is your subwoofer enclosure made so sturdily? To prevent the enclosure itself from vibrating with the large changes in air pressure going on inside. As the enclosure expands and contracts with that pressure, the outside of the enclosure will create pressure waves that you can hear. It's a transducer itself.

 

[abdo123]

Wouldn't the size of the wall cavity have a significant impact on performance - just as the size of the box impacts the performance of regular box speakers? Wouldn't insulation in the wall have a significant effect too?

And, as Chromatischism said, drywall or lathe & plaster will vibrate with bass, a lot more, I think, than the braced MDF of a regular speaker enclosure. Won't that be an issue?

the size of the wall cavity and the cabinet are not really comparable, it's more like the entire size of the wall vs the size of the cabinet.

speakers with infinite baffles do not radiate behind the driver/wall.