In Wall Speakers

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dawaro

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In Wall Speakers
« on: 28 Nov 2005, 07:11 pm »
Are there any plans to develope a line of in wall speaker kits?
Could the Kit 61 be modified for in wall use?
I am looking at building the 61's for my surrounds but I have limited floor space, if I could stick them in the wall it would really help.

Kevin Haskins

In Wall Speakers
« Reply #1 on: 28 Nov 2005, 08:04 pm »
We are working on something for CES that is close to what you’re asking for.   It's a 5" deep version of the KIT61 for wall mounting.   You could obviously sink it into the wall but a standard 2'x4' wall isn't deep enough for the Extremis.   It would still stick out proud a little.

The other issue is you give up some bandwidth by going sealed and smaller.   The solution to that is a simple LT circuit to extend their bandwidth in a sealed enclosure.   I've done some prototype boards for a high quality LT circuit that we are going to use with our Hypex amplifiers.    

From my initial modeling it allows us to get just as deep as the standard Kit61 while dialing in a sealed box Q of 0.65 for a very tight musical bottom end.   Overall cabinet dimensions are 14" (tall) x 8.5" wide x 5" deep.    The f3 is currently designed at 45Hz and with wall mounting and room gain you get flat response to the mid 20s.   I'll probably be playing with the EQ curve to get them dialed in for 2Pi operation.   Mounting them on the wall profoundly affects the bottom end.   You don't have any baffle step loss and you get a lot of reinforcement from the close room boundary.   The active EQ allows us a lot of freedom to play with the response that isn't so easy to do with passive networks in this frequency range.

I've also got an MTM center designed in the same profile for wall mounting and a simple tower of the same dimensions with the same bandwidth.    I'll be posting pictures and details over the next couple months.    The skinny speakers are going to be called our Silhouette Series.   We are going to have finished designs available (both speakers and subs) and I'll probably have options for all current kits where we offer the LT circuit and the amplification so that you can build greatly reduced size versions of all current speaker designs.

Should be lots of fun.  Imagine having the bandwidth and SPL capabilities of the LCR, 261, 2641, 61 all in a speaker that is no more than 5" deep!   In addition, you get your choice of sealed alignments with the LT circuit.    Makes them much more wife & room friendly and really doesn't add that much to the total cost.    The Hypex amps are simply awesome... much better than 99% of what you can buy off the shelf from a retailer.   All my speaker designs are voiced with the Hypex amplifiers so forcing people into using them has been one of my evil plans.  ;-)

kfr01

In Wall Speakers
« Reply #2 on: 28 Nov 2005, 10:50 pm »
lol.  I don't think I'll let my wife see this post.  Yes, I'll file this away so she isn't upset that she could have a 5" deep tower instead of the 2641 in its full-blown and overbuilt glory.   :lol:

Anyway.  This is a great idea Kevin.

Have you seen this thread at diyaudio?

http://www.diyaudio.com/forums/showthread.php?s=&threadid=63078

Some sort of soundcard + software + hypex amps package might be neat and more flexible than a solid state solution.  Just an idea ... possibly a competitive alternative to Tact / Deqx devices for the customers (I assume many) that already use a computer for their audio.

Kevin Haskins

In Wall Speakers
« Reply #3 on: 29 Nov 2005, 07:17 am »
Quote from: kfr01
lol.  I don't think I'll let my wife see this post.  Yes, I'll file this away so she isn't upset that she could have a 5" deep tower instead of the 2641 in its full-blown and overbuilt glory.   :lol:

Anyway.  This is a great idea Kevin.

Have you seen this thread at diyaudio?

http://www.diyaudio.com/forums/showthread.php?s=&threadid=63078

Some sort of soundcard + software + hypex amps package might be neat and more flexible than a solid state solution.  Just an idea ... possibly a competitive ...


Ha.... I wouldn't loose any sleep.   The 2641s are great and there is something to be said for keeping things simple.  :-)

I'd say in response to that thread that I have a hard enough time getting people to build a simple cabinet and simple crossover network correctly!   Having something as complex as the PC controlled crossover, room correction and PC based system control sounds about as attractive to me as kidney stones.    :-)

The main problem I have with these systems is that you really need to have a background in acoustics to use them.   You know that monkey and the gun saying?  

A couple specific issues I have with the entire computer based super DSP systems:

#1.   The issue with the audibility of phase is not supported by research.    In my opinion, you should start with trying to solve the problems that have shown to have the highest correlation with perceived sound quality.   As an engineer you try and conquer the largest problems first.   Why place such a high priority on correcting something that is only audible with certain test signals?  

#2.   So-called room correction has a number of problems.   A measured in-room response has all kinds of data, some of which may be easily correctable and other which isn't.   Also... I believe in optimizing the system for wide even response.   I don't believe in optimizing for one axis, which is what the room correction is doing if you just apply the inverse of the uncorrected response.  Much of the low frequency data is going to vary a great deal from point to point in the room.   You also have modal ringing which cannot be EQed out either with analog or digital filters.   You need absorption in the room to damp it.    Room correction will not deal with early diffraction effects; it's not the panacea that many people are claiming.   It is a way to throw a lot of money at a problem that isn't completely controllable via electronics.   It's another toy that companies want to sell.   It could have some beneficial use if used correctly but most companies selling them are overstating their usefulness.

#3.  You are going to need multiple channels of amplification for each speaker.   This drives the cost WAY up so it’s only a solution that will appeal to the very rich.   Good five channel amps are expensive by most people's standards.   For a multichannel setup you would be looking at a minimum of ten channels of amplification (two-ways) or more likely fifteen to twenty channels to do the entire surround system in more than two-way configurations.   At the very minimum double your amplifier budget.   More likely you will at least triple your amplifier budget.  

#4.  I'd say the system is too complex for 99.999% of the public.   Hell... my wife doesn't know how to use the TV remote.   How many people can set up a multi-PC system and integrate all that technology?   How many people have a background in physics or acoustics that can actually understand how to design the system?   Having the tool doesn't remove the need to understand how to use it.

For people who want to make the most of their money a traditional passive crossover is the way to go.   If he had spent more time optimizing his passive solution and the room I bet he could get results VERY close to his digitally corrected one.   The resulting system would only need one amplifier, would cost a fraction of the PC based one and would be easy to operate and integrate with more mainstream sources and other equipment.

Leave the bleeding edge of technology to those who have a desire to bleed.   Some day... the parts that make sense (much of their functionality doesn't) will filter down to those of us with workingman budgets.

kfr01

In Wall Speakers
« Reply #4 on: 29 Nov 2005, 01:25 pm »
That all makes perfect sense.  Reading more of that diyaudio thread, it does seem like solutions such as the PC-based XO/DRC are in the very early stages of infancy-best to wait a few years and reevaluate-definitely the bleeding edge.

It sounds like the next upgrade step that might make the most sense for me is traditional room treatment.

I like your design philosophies; I'm looking forward to seeing the hypex + LT modules you develop and the Silhouette Series you release.  A HT rig is a possibility for me in the not too distant future, so the MTM wall mount center sounds like a device the wife and I will be interested in.

cOz

  • Jr. Member
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In Wall Speakers
« Reply #5 on: 29 Nov 2005, 03:07 pm »
Hey Kevin,

I really like the direction you're taking your designs.  Very exciting!

Kevin Haskins

In Wall Speakers
« Reply #6 on: 29 Nov 2005, 04:43 pm »
Quote from: kfr01
That all makes perfect sense.  Reading more of that diyaudio thread, it does seem like solutions such as the PC-based XO/DRC are in the very early stages of infancy-best to wait a few years and reevaluate-definitely the bleeding edge.

It sounds like the next upgrade step that might make the most sense for me is traditional room treatment.


Very smart....

I don't want to sound like an Ogre... the things you can do with a DSP are pretty cool.   There is a lot you can do there that you cannot do in the analog domain.   The problem is that perfect phase is not obtainable for anything more than one position in space..... DSP or not.   It's importance is not even being questioned by the people who are working on this gear.   What I'd rather see is a DSP that corrected driver non-linearity.   I can handle the crossover in the passive domain and I've convinced myself that the so-called phase issues introduced via passive crossovers is not the evil demon that many profess.  

DSP can be useful for some moderate parametric EQ ability, driver FR correction and some day, driver non-linear behavior correction.   It could be used for low crossover points when it's more cost effective than a passive solution.   I don't want some system trying to analyze room reflections and correct for them.   Move 1' to the right or left and those corrections are no longer valid.   Stand up and those corrections are no longer valid.    

Optimizing a speaker on one axis is attractive from the point of showing a nice smooth response curve and DSP is more flexible than passive crossover for shaping the response of the speaker.   The problem is that if you optimize at one point you are sacrificing at another.   The physical shapes and dispersion patterns of the drivers cannot be overcome for more than one axis at a time.   The result is that you often get poor off-axis response in exchange for that nice smooth response on-axis.   Sound like a good tradeoff?  For some it might but the current state of research is pointing in the opposite direction.   Good response across a window of dispersion looks to be more important than optimized response at one location.   Once you remove the microphone and put your head and ears in place the response at the ear suffers from comb filtering anyway.   In other words that nice perfectly flat line response is only an illusion used by companies to market their gear.    It's important to have a relatively flat frequency response on-axis but not at the total expense of off-axis behavior.   It's a balancing act and you would need a DSP that could collect data from across a window and intelligently choose a correction curve to optimize for that window.    That would be a good use for the computer/DSP system but it wouldn't allieviate the need for well engineered drivers and cabinets.   It would only be a tool for helping.   The room is still going to be in the equation also.... there is no way to equalize out the largest problems.  

Just my opinion.  ;-)

Kevin Haskins

In Wall Speakers
« Reply #7 on: 29 Nov 2005, 05:08 pm »
Quote from: cOz
Hey Kevin,

I really like the direction you're taking your designs.  Very exciting!


Thanks... I'm excited about them.    The Extremis with all that massive stroke is just begging to be used appropriately.  ;-)

klh

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In Wall Speakers
« Reply #8 on: 29 Nov 2005, 07:58 pm »
Which drivers will be used in the MTM... or is it really a WTW? Would you consider doing a wall mount WMT (641) and MTM center. Imagine upgrading to a wall mount WWMT (2641) and a WMTMW center. That's some serious potential! There is an amazing amount of potential :D.

kfr01

I have to say...
« Reply #9 on: 29 Nov 2005, 09:35 pm »
that I'm looking most forward to the possibility of a shallow LCR speaker for use behind projection screens.

Kevin Haskins

In Wall Speakers
« Reply #10 on: 30 Nov 2005, 01:17 am »
Quote from: klh
Which drivers will be used in the MTM... or is it really a WTW? Would you consider doing a wall mount WMT (641) and MTM center. Imagine upgrading to a wall mount WWMT (2641) and a WMTMW center. That's some serious potential! There is an amazing amount of potential :D.


The MTM is two Extremis and the Usher.  

Basically the product line will continue to evolve with the drivers we are already using.   I'm looking at a less expensive 3/4" dome but I've got some more measurements before I can call it fit for duty.   It has to be usable in a two-way and cross as low as 2K which limits our choices.

klh

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In Wall Speakers
« Reply #11 on: 2 Dec 2005, 01:06 am »
Would mounting these on the ceiling affect their performance/longevity? My brother-in-law wants a 7 channel HT and ceiling mounted vs side wall mounted surround speakers would be a much easier to install (and he probably wouldn't notice much of a difference between the sound coming from the side vs from above).

Kevin Haskins

In Wall Speakers
« Reply #12 on: 2 Dec 2005, 02:13 am »
Quote from: klh
Would mounting these on the ceiling affect their performance/longevity? My brother-in-law wants a 7 channel HT and ceiling mounted vs side wall mounted surround speakers would be a much easier to install (and he probably wouldn't notice much of a difference between the sound coming from the side vs from above).


No... they pretty much operate in any orientation.   I'll have some pictures around CES time.   They are prototype enclosures so the production items will be slightly different in finish.   The shape and size is going to be the same though.

klh

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In Wall Speakers
« Reply #13 on: 2 Dec 2005, 04:35 pm »
Looking forward to next month