A Compact Home Theater

About a year ago I started work on converting an under utilized and fairly large bedroom into my next home theater. The goal was to have a room that would serve as my office and library during the day and become a reasonably high performance theater when the blackout curtains were drawn. Since I wanted to conceal as much of the gear as possible, I decided I should go with active speakers. I really liked the JBL 708P which offered the level of performance I wanted in a relatively compact package.

I got to work drawing up plans. My idea from the start was to incorporate the speakers into bookcases and have a screen come down in front of them. The room is 13' 6" by 20'. Due to doors and windows, the only option was to place the screen on the long wall which meant the throw distance of my projector dictated I couldn't have bookcases any deeper than 12" on the screen wall. This was a problem. The shelves themselves would be 11" deep and the 708Ps are 11 1/2" deep before any cables are attached and no toe in is applied. I considered the 705Ps, but the performance hit was greater than I wanted to accept. (In an ideal world I would be going with M2s or Meyer Sound Acheron Designers, but they are both way too big to hide in a large bedroom!)

Obviously the next step for me was to consider custom DIY designs... since I wanted to use a compression driver up top and preferably a 2" or larger driver at that, everything I came up with was also too large. During this time I installed some Meyer Sound Ultra-X20s for a project at work. Before installing them I brought a pair home to test and was quite favorably impressed. These speakers are extremely compact for their capabilities and the imaging is extremely good. The speakers are a D'Apolito design with a 2" compression driver sitting between a pair of purpose built 5" woofers. One of the design features is a rotatable horn which allows the speaker to be used either vertically or horizontally.

After deciding to go with the Ultra-X20s, I needed to sort out my subwoofer situation. I had a Revel B112 I planned on using tucked under my desk in the room's corner, but I wanted to augment it primarily for smoothing out the bass response in the room. I added a pair of very unusual in-wall subs. Artison RCC-320 Mk2s. These subs are tiny, but pack a heck of a punch and are quite "musical" as well... (not one note bass). For the surrounds I decided to go with the shockingly tiny Meyer Sound MM-4XP. These speakers look like something Bose might have conjured up, but they are neutral, wide bandwidth, and will exceed Dolby or DTS reference levels in a room my size. They do compromise the upper bass in that they roll off below 135Hz, but for surround duty, I am willing to accept that.

My surround processor of choice for most home theaters is to go with one of the Lyngdorf surround processors with Lyngdorf's Room Perfect room correction. Since I will never use more than 12 channels in this room, the MP40 was the logical choice. Amplification... the Meyers are all active and use an outboard DC power supply. The Revel B112 has a plate amp— fingers crossed it will last. The Artison subs do require a dedicated amp so I do have a 1U 1000watt amp in the rack, but that's it. With this setup I was able to tuck everything in a tiny rack in my closet and satisfy the hidden equipment requirement.


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What to do with those Ultra-X20s?

Setting one up to be used as the center channel was a no brainer, but what about the left and right speaker? They could also be set horizontally on bookshelves, but then visually I have a lot of speakers in a row and also far less room for books... we have a lot of books! So, if I don't make the speakers disappear in the bookcase, what do I do with them? They are not exactly domestic use friendly. They are beautifully made from aluminum, but they are meant to be installed in a commercial space, not your home.

I decided to create speaker stands that would mimic the look of audiophile speakers and add a little bling. I designed them around the horn, locating them at seated ear height. The center channel remains below the screen since even a Stewart Micro-Perf screen will interfere with image quality at 11' which is my seated viewing distance. My favorite "acoustically transparent" screens are the newer woven styles, but these do not roll up.

After kicking around a number of ideas, I came up with these stands and this layout. The finish is a rubbed out dark metallic blue lacquer with machined and polished aluminum details. There are 4 M8 bolts holding the speakers in place. There are access holes in the rear to facilitate running the 5 conductor balanced audio and power cable up to the speakers and also to access the two lower bolts. The bases are 5/16" thick plate steel that was laser cut. Thanks Barry!


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Speaker details...

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...and a few more.

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To be honest, I'm kind of speechless on how good those stands turned out. Made me forget the original scope of the thread. Excellent work!

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Originally Posted by srm51555

To be honest, I'm kind of speechless on how good those stands turned out. Made me forget the original scope of the thread. Excellent work!

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Thanks!

The best compliment to date was when my resident artistic coordinator said that she actually liked them. :shocking:


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Originally Posted by Mr. Widget

…. The bases are 5/16" thick plate steel that was laser cut. Thanks Barry.

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You are super welcome. :)

They turned out remarkable. Well done.

I find those speakers very interesting. I hope not to derail but the offset of the woofers and the center to center spacing method is something I never would have conjured. Fascinating.

It always makes me really ponder what I must not know when someone seems to break “the rules” and yet produces something the real professional market finds acceptable.

Thanks for the grills off pics.

My best.
Barry.

You made those stands?? Wow indeed, very nice.

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Originally Posted by DerekTheGreat

You made those stands?? Wow indeed, very nice.

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Yes, but I used to have a business building prototypes and acquired many specialized skills along the way. That said, I hadn't done anything like this in over 15 years and boy was I rusty. I had to re-learn a few tricks and I no longer have a spray booth or some of the other niceties you have when it is your full-time gig. Thanks though... appreciated.


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Originally Posted by 1audiohack

I find those speakers very interesting. I hope not to derail but the offset of the woofers and the center to center spacing method is something I never would have conjured. Fascinating.

It always makes me really ponder what I must not know when someone seems to break “the rules” and yet produces something the real professional market finds acceptable.

Thanks for the grills off pics.

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Yeah, I opened them up to reorient the horns when we installed some for a client's project and had the same thoughts. But thinking about it, I realized these speakers are actively bi-amped and have full DSP control with frequency, time, and phase correction. Meyer can clean up any undesired effects. The physical layout is designed to control their vertical and horizontal polar responses which are tightly controlled.

The results are a stunning performer in a micro package (micro when you consider their output capabilities). I do massage their voicing with the Lyngdorf processor to bring them in alignment with my goals and taste, but there is nothing analog about this system so there is nothing to lose.


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Hello;

If you would rather this go outside your nice thread here please edit me out and we’ll carry on elsewhere.

I am not at all looking down my nose at these speakers. The fact that they work well opens up some DIY design possibilities that I may never have considered and this excites me.

Can you tell if and how the back of the horn may be treated or what it looks like back where we can’t see?

Thank you. :)
Barry.

No edits needed... I am equally intrigued.

When I have a few minutes, I'll pop a grille off and shoot a couple of detailed photos.
To your point about opening up new DIY options. I went this route (using an off the shelf speaker instead of a DIY design) because:

A. Meyer Sound has an extensive engineering team with scientists and engineers on staff and can come up with crazy stuff like this where there is no way I could pull it off.

B. I wanted the keep the performance bar as high as possible and maintain as minimal visual presence as possible in a room with few options.

FWIW: I also considered the JBL CBT 70J-1. I have used them in a couple of my HT designs and they are surprisingly good too and at a lower price point, but they would have required 3 channels of serious amplification and the center channel would have been a problem.


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Originally Posted by 1audiohack

Can you tell if and how the back of the horn may be treated or what it looks like back where we can’t see?

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Doesn't appear to be treated... and the back has ribs, but I assume they are to stiffen the casting. Not sure.


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Many thanks mister Widget.

That leaves me much to ponder.

Barry. :)

Very nice! Like those stands. That looks like a big screen! Neat subs how are they?? They look small and compact you really get 1st octave out of them??

Rob :)

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Originally Posted by Mr. Widget

Yes, but I used to have a business building prototypes and acquired many specialized skills along the way. That said, I hadn't done anything like this in over 15 years and boy was I rusty. I had to re-learn a few tricks and I no longer have a spray booth or some of the other niceties you have when it is your full-time gig. Thanks though... appreciated.


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You're welcome, they are fantastic. Sounds like that business was a special period in your life. I'm intrigued about these prototypes you made and who you rubbed elbows with in the process. I used to be able to paint too, definitely rusty, although I'm sure I could still powder paint just fine. Liquid paint? I've run and sagged every job I've done the past year. I want to blame the rattle cans, but I feel I should remember better.

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Originally Posted by 1audiohack

The fact that they work well opens up some DIY design possibilities that I may never have considered and this excites me.

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Originally Posted by Robh3606

Neat subs how are they?? They look small and compact you really get 1st octave out of them??

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The subs are way out of the box thinking and use some pretty unconventional design ideas. The boxes are filled with activated charcoal to increase their apparent volume over fiberglass, wool, etc. And the enclosures are extremely rigid being machined from a heavy extruded aluminum sections. These things are tiny at about 14" square by only 3 1/2" deep, yet they put out significant low bass output. The specs for a pair -3dB at 24Hz and an output capability of 109 dB at 40Hz.

Read the attached white paper to get some very interesting info that could be useful in DIY applications.


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Originally Posted by Mr. Widget

...These things are tiny at about 14" square by only 3 1/2" deep, yet they put out significant low bass output. The specs for a pair -3dB at 24Hz and an output capability of 109 dB at 40Hz.
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I am speechless.
How do they get that. I built subs last month and they easily weigh over 150 pounds each.

Really interesting:hmm:

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Originally Posted by macsic

I am speechless.
How do they get that. I built subs last month and they easily weigh over 150 pounds each.

Really interesting:hmm:

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Take a look at the white paper. They pay a price sensitivity wise so you just use more to get your SPL. Thanks Mr Widget for the white paper.

Rob :)

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Originally Posted by Robh3606

Take a look at the white paper. They pay a price sensitivity wise so you just use more to get your SPL. Thanks Mr Widget for the white paper.

Rob :)

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Yes! I took a quick look at the document and it made me think of the principles of AirMotionTranducer (AMT) but for very low frequencies.

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Originally Posted by Robh3606

Take a look at the white paper. They pay a price sensitivity wise so you just use more to get your SPL. Thanks Mr Widget for the white paper.

Rob :)

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And the price in $$$. ;)

Four of these little guys and their dedicated amp is north of $6K!

That is fine if you have clients who don't have room to hide conventional subs, the room isn't terribly large, and they have deep pockets, but otherwise these subs are not a solution for all projects. They do point to interesting potential solutions for other DIY designs though and why I thought they may interest folks here.


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Very cool subs - look very similar to Dynaudio's RCC sub:
Attachment 91120
I also remember Bohlender Graebener did something similar years ago - I think theirs were (12) 3.5" woofers, six on each side, facing each other:
Attachment 91121

You're right about the efficiency, but I love the vibration cancellation. I used to have a Triad music sub with opposing 10" woofers, and currently have a sub mounted under my deck with two opposing 12" subs - sounds great, and the lack of vibration makes it really hard to locate, except by careful listening.

Great project all around - really nice to see what someone with next level talent can put together :)

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Originally Posted by HCSGuy

Very cool subs - look very similar to Dynaudio's RCC sub

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Thanks for sharing this, I didn't know that Dynaudio was also offering an RCC sub. Looking at the photos and checking out the Dynaudio website, I would guess that Dynaudio is either rebadging the Artison unit or is building it under a license agreement. I believe the term RCC was invented by Cary Christie. Interestingly the price of the Artison unit and the Dynaudio model is the same.

In the photo the woofers look like the original MK I version of the Artison sub, the ones I have are the MK II version with a different cone/dustcap and a modified surround.

Regarding those BG subs, it is interesting that BG (now Wisdom Audio) and Artison are both located near each other just south of Reno NV. Coincidence?

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Originally Posted by HCSGuy

Great project all around - really nice to see what someone with next level talent can put together :)

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Thanks, not sure I can live up to the phrase "next level talent", but decades of experience (aka: lots of screw ups) does have its benefits.


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That's a great looking system! Excellent planning and execution Mr. Widget. I'm sure it sounds great too. Movie night just got an upgrade at your house.:)

Great work on that office system Mr Widget. Yes keeping the co-ordinator happy is the best thing you can do.

As an update on the system and to provide additional info on these crazy subs... last weekend while Rob was having some rainy day fun on the East Coast, I also played around with my system. I decided to try moving these "in-wall" subs directly behind the left and right speakers. I had never installed them in the walls of my room and had them deployed behind the listening couch with a 12" Revel B112 sub in the right front corner of the room.

While this sounded great, as a fellow audio hobbyist who can never leave well enough alone, I decided to try an experiment. Without making any changes to delays, gain, or EQ, I pulled the two RCC-320 subs from behind the couch and placed them up against the wall and next to each end of the front bookcase directly behind the left and right speakers. I shut off the 12" woofer and powered the little subs up... it sounded really good. Surprisingly good.

I removed the B112 subwoofer from the room and then reset the Lyngdorf pre/pro with the correct gain and delay and ran RoomPerfect correction again to take these changes to the system into account. I then gave the system a serious listen. I was absolutely blown away. In this configuration not only was the system still quite capable of being a movie powerhouse it upped the game into a stellar two-channel music listening system. I literally sat there slack jawed. How in the world could these two tiny subs do that?! Deep, powerful, tight, tuneful bass... at any reasonable or even unreasonable SPL level. Unbelievable!

This weekend I invited a couple of audio buddies over to get their take. I wanted to make sure I hadn't gone mad! Both friends have serious systems at home. One has M2s and the other has a large DIY system. They were both as equally stunned as I had been when I first reconfigured the system. They commented on the well integrated bass that was deep and musical, and at the wide and seriously deep soundstage! These time aligned, phase corrected, narrow baffled Ultra-X20s sounded huge or laser focused depending on the music being played. I played a variety of tracks before revealing the subwoofers which are completely hidden behind the curtains behind each speaker. This creates the illusion visually and audibly that the huge deep bass is coming from the relatively small stand mounted speakers. Pulling back the curtain to reveal the stupidly small subwoofers really floored my friends. We three have decades of experience with all manner of audio gear and seeing these tiny subwoofers and knowing what we were hearing just doesn't seem possible.

The take away I'd like to provide is that sub placement is absolutely critical. Understanding room modes and how placing 2 or more subs around the room to get better and more even bass distribution while very helpful, don't lose sight of the integration with your main speakers, especially in two channel playback. Beyond that, for those inclined... I think there is some serious DIY potential here with this slot loaded balanced configuration. These subwoofers are nothing short of miraculous.


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Hello Mr Widget;

I love this thread and this project. For one thing it shows that technology and creativity must in fact be improving our audio experience.

The little Meyers just break my brain. If diffraction is even a thing and electronic solutions to physical problems are at best just a bandaid then these just make me wonder what I don’t know or understand. I certainly hope to hear them.

On the next to explore front I just received four cubic feet of activated charcoal for experimentation that I hope to get to this weekend.

I have toyed a bit with slot loaded subs and there is something to the increased radiation resistance created by this loading method.

Thank you for sharing! I hope you’re not done yet. :)
Barry.

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Originally Posted by 1audiohack

... The little Meyers just break my brain. If diffraction is even a thing and electronic solutions to physical problems are at best just a bandaid then these just make me wonder what I don’t know or understand. I certainly hope to hear them....

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Barry, I just looked at the data sheet and it appears (but doesn't say) that the crossover point to the horn is pretty low, perhaps as low as 600hz. Down to 1khz even, diffraction isn't going to be an issue. Those 2 woofers are acting as one, and with the horn are acting as a concentric point source like the Altec 604 or UREI 801. There will be a little rippling of interference from the horn but it's low enough in frequency not to be a big deal. The drivers also appear to be physically time aligned and the advantages of that can't understated. If it was an MTM design that crossed over at a more typical 2khz-3khz range, the interference would be problematic.

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Originally Posted by rusty jefferson

Barry, I just looked at the data sheet and it appears (but doesn't say) that the crossover point to the horn is pretty low, perhaps as low as 600hz. Down to 1khz even, diffraction isn't going to be an issue. Those 2 woofers are acting as one, and with the horn are acting as a concentric point source like the Altec 604 or UREI 801. There will be a little rippling of interference from the horn but it's low enough in frequency not to be a big deal. The drivers also appear to be physically time aligned and the advantages of that can't understated. If it was an MTM design that crossed over at a more typical 2khz-3khz range, the interference would be problematic.

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Meyer has a larger version called the Ultra-X40. The 40s up the woofers from 5” to 8” and the compression driver bumps up to 3” from the 2” driver in the Ultra-X20. I have compared them with the Ultra-X20s. In a direct comparison the 40s have a smoother and more musical midrange. Not night and day, but it is there.

Unfortunately the 40s are too large to satisfy my aesthetic requirements. I am relying on a bit of DSP “sweetening” from my pre/pro to take care of this.


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Only Meyer would be ballsy enough to take the approach that they did ( & then get away with it ).

First the applied EQ curves.

And then raw impedance of the drivers.

Followed by the raw response of the Ultra X40 drivers.

My pics are simple screen grabs ( enlarged ) taken from a pdf created by a German company. Go to Meyer Sound X40 Technical Review.pdf

I've used these X40's a couple of times. Some comments later.

:)

Interesting, thanks for sharing!

From what I have been told, the idea is to create a point source system similar to some of the L Acoustics designs but with better pattern control.


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Originally Posted by Mr. Widget

The best compliment to date was when my resident artistic coordinator said that she actually liked them.
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Not surprising you heard that comment. And not surprising they turned out that way. Very nice work.

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Originally Posted by G.A.

Not surprising you heard that comment. And not surprising they turned out that way. Very nice work.

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Thanks very kind of you. It appears you have more faith in my skills than she does.

During the many weeks it took me to build them and apply the 12-14 coats of lacquer I kept hearing her say, “Why are you putting in that much time on those hideous structures? A U-Haul box will look better.” Ouch!

So when she told me how much she actually liked the way they turned out, it was especially satisfying.

The fact that sonically the system turned out better than expected was even more icing on the cake!


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Mr Widget, those stands are wonderful!! Excellent attention to detail, but you have always shown this in all of the work I have seen here! The subs are certainly peaking my curiosity. Thanks for sharing your new system, looks like a wonderful place to escape.

Over Thanksgiving I was finally able to finish the project and install the projector and surround speakers properly! For almost a year now I have had the projector sitting on a wall mounted temporary shelf between these two bookcases.

As I am sure many of you can relate, life gets in the way and that causes some projects to move forward at a glacial pace.


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As seen above, in the evening the surrounds are well hidden in the shadows, but during the day they are more visible, but even though they seem to jump out at you in these pictures, there is enough going on in the room that the speakers are not the first thing you notice.

The Meyer Sound MM4-XP speakers really seem more like something Bose would come with, but they are capable of kicking butt... and are packed in these micro cabinets.


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I love the use of space. Book cases and theater screen areas are useless when not in use and this makes efficient use of both in the same space.