HT design around Magneplanar?

[Dave Raue]

I'm planning/designing a media room in new house combining 2-chan audio with a modest HT system. Let's start with the room itself. The room isn't finished so I have some latitude in terms of layout and design. That said, overall dimensions are limited to foundation size which is roughly 24' long x 12" wide. Ceiling is 8' with a few odd intrusions from soffits for ductwork etc. Seems like enough space to reasonably work with. I can make the room shorter to avoid L=2xW resonance problems. I've also got a nice collection of Tube Taps to play with.

Now it starts getting trickier. My intent is to set up a dual-use system: 7.1 HT sound that also doubles as a 2-channel audio system. HT system could be simplified to 5.1 if that makes more sense. My hardware allows this to be done quite easily. Front speakers run off a dedicated, high end amp that is fed by either the HT amp or my 2-channel audio system depending on intended use. Specifically, electronics for 2-chan audio are Schiit Yggy DAC, Freya S preamp and Loki Max for EQ (which also switches sources for the main amp). HT box is a Denon AVR-x3600h. Video is on 80" Sony monitor. Everything is fed by either streaming sources or my local file server. Front speakers would be set apart by 80" monitor. Reflections the monitor might be an issue, I'll just have to see (more on that below).

Now it gets a lot trickier. I'm quite stubborn on finding the best use of the equipment I already have. It has served me well and would be expensive to replace with meaningfully better stuff IMO. What I have in mind is this:

• Front & 2 channel listening: After building the room I'd figure on optimizing the 2-channel system and TV placement. Fronts would be Magneplanar MGIIIa's driven by Mark Levinson No 332. For 2 channels this is an astounding combination. I assume it would similarly nice for the HT front.
• HT Center: Magneplanar MMG C. Has very clear vocals.
• HT surrounds and rear surrounds: TBD. Several choices. The grab bag includes MG Quart One's, KEF LS50's and Maggie SMGc's. My initial thoughts are to use SMGc's as rear surrounds. They're probably too directional to work well as side surrounds and are best when away from the walls anyway. Then use one of the bookshelf spkrs as side surrounds. The LS50's strike me as better than they need to be for that purpose, but who knows?
• Sub: old, reconed Velodyne ULD-12. Yeah, I know, an antique, but it works and I find it fine for most of my video stuff. I'm a lot pickier about 2-chan than HT sound.

So, looking for comments & suggestions on all this, but please refrain for "just experiment to see what sounds best" remarks. Same goes for "ditch such and such and buy XYZ." The point is to best use what I got. In any event I'll certainly do a lot of switching around as there are lots of permutations with the surround speakers. Added to that is the reality the placing Maggies is a challenge in itself. I'd like to start the process using principled design concepts or, failing that, at least educated guesswork, not open-ended experimentation. Thanks in advance and happy listening! Cheers,

 

[Swerd]

You have a room about 24' long × 12' wide, and you want to make use of Magneplanar MG IIIa speakers as front left & right speakers along with an 80" TV.

The easiest question you asked is whether to go for 7 or 5 channels. Usually, 5 channels work well if you have one row of seating. If you have two rows of seats, such as two sofas, one behind the other, 7 channels can work well.

The MG IIIa speakers you have (want?) are bi-polar design speakers. Right? They need plenty of space between them and the wall behind them. They don't work well if too close to that wall. So the answer to how many rows of seating can be answered after you know how far out into that room the MG IIIa speakers must be. I'd make a guess that 5 channels will be all you can cram into that room. And if you start with 5 channels, it will be easy enough to add the side surround channels later, if you want.

Your 80" TV set is nearly 6' wide. How wide are the MG IIIa speakers? How far away from the side walls must they be to sound well? Also, will that 80" TV screen between the MG IIIa speakers block too much sound reflected from the wall behind them? The only rooms I can remember with large Maggies all were long before Home Theater. They had plenty of open space between them. You see where I'm going … will a 12' wide room be wide enough?

Your other questions will be easier to address after you've learned where in your room – how far from the rear wall and the side walls – you must put those MG IIIa speakers.

If it isn't already obvious, I don't own Maggies or any other bi-polar speaker. But I am aware of the placement issues with bi-polar speakers. I'm not aware of anyone who has attempted to combine a bi-polar 2-channel system with a multi-channel surround sound system, but I wouldn't be surprised if someone has. You clearly have thought about this tough problem more than I have. I certainly don't have specific detailed answers to your questions. I've only tried to narrow down the list of unanswered questions that you face.

 

[lovinthehd]

And if you start with 5 channels, it will be easy enough to add the side surround channels later, if you want.

You mean add rear surrounds for a 7ch setup since basic surrounds (side I suppose) are already in use in a 5ch setup?

 

[Swerd]

You mean add rear surrounds for a 7ch setup since basic surrounds (side I suppose) are already in use in a 5ch setup?

I was thinking to first use rear surround speakers in a 5-channel set up, and later, if desired, add two side surround speakers. But I'm not sure it really matters which comes first.

@Dave Raue
I should also add this to my previous response to the OP. Put most of your speaker money, thought, and effort into the front three speakers. The rear & side surround speakers are much less important for HT. You can save money at those speaker positions, and you can make life much simpler by choosing small mono-pole speakers instead of bi-poles, such as those Magnepan SMGc speakers you mentioned.

 

[lovinthehd]

I was thinking to first use rear surround speakers in a 5-channel set up, and later, if desired, add two side surround speakers. But I'm not sure it really matters which comes first.

@Dave Raue
I should also add this to my previous response to the OP. Put most of your speaker money, thought, and effort into the front three speakers. The rear & side surround speakers are much less important for HT. You can save money at those speaker positions, and you can make life much simpler by choosing small mono-pole speakers instead of bi-poles, such as those Magnepan SMGc speakers you mentioned.

IIRC there are some avrs if you connect to rear surround before surround, just won't work. You'd still use the surround connections even if you're setting the surrounds more in the rear surround positions....

 

[William Lemmerhirt]

Someone had to mention the sub… guess I did!

 

[Wardog555]

I was thinking to first use rear surround speakers in a 5-channel set up, and later, if desired, add two side surround speakers. But I'm not sure it really matters which comes first.

It matters as I've seen one person use rear surrounds then added sides and it completely changed their experience.

Always go sides first as that's where the sound mix goes first. Then the rears but it's only used rarely. Like atmos speakers. Rarely used.

Side surrounds are used significantly more.
Choose any action scene and hear the difference between rears vs sides.

My 5.1 is in the surrounds/sides terminals always.

 

[Swerd]

It matters as I've seen one person use rear surrounds then added sides and it completely changed their experience.

Always go sides first as that's where the sound mix goes first. Then the rears but it's only used rarely. Like atmos speakers. Rarely used.

Side surrounds are used significantly more.
Choose any action scene and hear the difference between rears vs sides.

My 5.1 is in the surrounds/sides terminals always.

Save this 'debate' for another time & place. The OP hasn't responded yet, and the question over sides vs. rear channels doesn't address his big question about building a HT around large bi-polar speakers.

 

[ski2xblack]

@Dave Raue Hey, Dave. Thanks for having a "room first" perspective on this.

I think that the cardioid dispersion and high freq beaminess of your mains will actually do well in your long, narrow room. At least they'll give you some room to play with when juggling the variables to reach desired goals, like mitigating the room's influence, size of desired sweet spot, proper separation of left and right channels for stereo immersion, etc.

Most of that will concern the placement of the speakers as well as the intended listening position. I would not compromise on at least 4' between the speakers and the wall behind them. That's to ensure adequate delay and attenuation of the reflected sound coming from the back of the speaker. Too little of that and we perceptually homogenize the direct and the reflected sound with less satisfyng, Bose-ish mush results.

Laterally, wider placement is better, as long as they're not so close to the side walls that acoustic interactions become an audible tell. The cardioid/beamy dispersion of your mains will buy some wiggle room here.

And listening distance to the mlp will dictate the trade offs inherent to a rig set up on the short wall of a long room, between a narrow but exquisite sweet spot with excellent immersion at closer distances, or a wider sweet spot but compromised channel separation and immersion if the mlp is further away. Of course the surround aspect will ameliorate some of that, but the system should hit the target at the intended mlp in stereo as a baseline.

Hopefully that center channel speaker is up to the task, and devoid of resonances or any otherwise audible tells. That seems to be a significant challenge for your setup, given the mains it's trying to blend with. (That's not meant as a criticism of that particular center speaker, but at a more basic level of system setup, where the ideal is identical L, C, and R speakers.)

I'll second what others have said, good feedback so far. Good luck with it, Dave, and enjoy the music!

 

[Dave Raue]

Thanks to all! I'll try to flesh things out a little. I know that planar speakers are a little outside the box in the world of HT. What I'm trying to do even more so perhaps.

Anyway, by way of background, my old room was long and skinny, roughly 12' w x 24' L. The video and 2 channel systems were at the ends of the room with listening/viewing back-to-back in the middle. One side of the room had a 12' opening into a hallway and stairs and so would be considered partially open.

In this case the TV was about 18" out from the wall and flanked by the small maggies. This puts the SMGc's about 1' from side walls and 19" from the rear. Rear surrounds were on a ceiling beam about 2' behind viewing the position. This placement was absolutely NOT optimized for anything. It's just where stuff fit and I lived with it. Honestly I'm not so critical about video sound.

The 2-channel system was better set up. Large Maggies were about 4' of the front wall and 12" from the sides. My experience has been that distance to the front is more important than the sides. Listening seat formed a near perfect equilateral triangle with the speakers in a kind of near-field setup. The sound would bring tears to your eyes.

So, now I basically want to replicate (or improve on) the previous 2-channel setup. I assume that front speakers wouldn't be too far from where they were in previous room. Listening position could be farther back if that works better. Then TV someplace between front speakers, exact distance TBD depending on effect on sound. In all of this I'm assuming that what sounds good for 2-chan will also sound good for video. Sounds like I ought to stick with 5.1 and play the rear speakers to see what works best. Given room size there would be plenty of space for the small Maggies to breath.

So, open questions are room dimensions (I only get 1 shat at that), suggestions on placement & experimentation and possible acoustic treatments. I do have some large bass traps on hand and can get/build other treat panels as well. Thanks again and looking forward to comments. Cheers,

[sidebar - made a similar post on AVS forums and the comments boiled down to 'get new equipment.' Utterly unhelpful. Not the place for me I guess. ]

 

[TLS Guy]

Thanks to all! I'll try to flesh things out a little. I know that planar speakers are a little outside the box in the world of HT. What I'm trying to do even more so perhaps.

Anyway, by way of background, my old room was long and skinny, roughly 12' w x 24' L. The video and 2 channel systems were at the ends of the room with listening/viewing back-to-back in the middle. One side of the room had a 12' opening into a hallway and stairs and so would be considered partially open.

In this case the TV was about 18" out from the wall and flanked by the small maggies. This puts the SMGc's about 1' from side walls and 19" from the rear. Rear surrounds were on a ceiling beam about 2' behind viewing the position. This placement was absolutely NOT optimized for anything. It's just where stuff fit and I lived with it. Honestly I'm not so critical about video sound.

The 2-channel system was better set up. Large Maggies were about 4' of the front wall and 12" from the sides. My experience has been that distance to the front is more important than the sides. Listening seat formed a near perfect equilateral triangle with the speakers in a kind of near-field setup. The sound would bring tears to your eyes.

So, now I basically want to replicate (or improve on) the previous 2-channel setup. I assume that front speakers wouldn't be too far from where they were in previous room. Listening position could be farther back if that works better. Then TV someplace between front speakers, exact distance TBD depending on effect on sound. In all of this I'm assuming that what sounds good for 2-chan will also sound good for video. Sounds like I ought to stick with 5.1 and play the rear speakers to see what works best. Given room size there would be plenty of space for the small Maggies to breath.

So, open questions are room dimensions (I only get 1 shat at that), suggestions on placement & experimentation and possible acoustic treatments. I do have some large bass traps on hand and can get/build other treat panels as well. Thanks again and looking forward to comments. Cheers,

[sidebar - made a similar post on AVS forums and the comments boiled down to 'get new equipment.' Utterly unhelpful. Not the place for me I guess. ]

I assume you are feeding the Mark Levinson from the preouts of the Denon. I would strongly recommend a better sub and actually two. I would use them for two channel listening and HT. The bass is the weakest feature of the Maggies, and a couple of subs will improve them greatly.

 

[William Lemmerhirt]

I assume you are feeding the Mark Levinson from the preouts of the Denon. I would strongly recommend a better sub and actually two. I would use them for two channel listening and HT. The bass is the weakest feature of the Maggies, and a couple of subs will improve them greatly.

Agreed. Quality bass is the foundation for HT and music both. Having high quality subwoofers can easily elevate the sound quality of the entire system.

 

[Dave Raue]

Yes, ML fed by Denon, albeit indirectly via Schiit Loki Max equalizer - a slick unit, BTW, with switchable RCA and balanced inputs, making it great for this purpose.

Anyway, yeah, I hear you guys. Weak low end seems to be a recurring Magneplanar theme. Yet others are untroubled. Magnepan themselves told me that udtaded MGIIIa's are better than newer 3.7 series (larger diaphragm). I guess I fall into that camp, I've never found the MGIIIa's lacking, at least not for normal music. I've wondered if the maggie-poor-bass crowd never heard the big ones and/or the amp wasn't up to the task. The ML 332 is an absolute beast, 400WPC into 4 ohms. It positively kicks ass, so I've always suspected that there's a contribution from the 332 that partially compensates.

Admittedly, video is something else. The music I listen to doesn't have seat rumbling explosions, plane crashes, etc etc. In my old room I was actually content with the old UDL-12 and small Maggies. OTOH, I don't know what I was missing. And I know for sure that the MGIIIa's go much lower than the SMG's. At this point my inclination is to postpone the sub problem until the rest is set up as best I can manage. There's still a lot to figure out with room design and planar placement. Cheers,

 

[TLS Guy]

Yes, ML fed by Denon, albeit indirectly via Schiit Loki Max equalizer - a slick unit, BTW, with switchable RCA and balanced inputs, making it great for this purpose.

Anyway, yeah, I hear you guys. Weak low end seems to be a recurring Magneplanar theme. Yet others are untroubled. Magnepan themselves told me that udtaded MGIIIa's are better than newer 3.7 series (larger diaphragm). I guess I fall into that camp, I've never found the MGIIIa's lacking, at least not for normal music. I've wondered if the maggie-poor-bass crowd never heard the big ones and/or the amp wasn't up to the task. The ML 332 is an absolute beast, 400WPC into 4 ohms. It positively kicks ass, so I've always suspected that there's a contribution from the 332 that partially compensates.

Admittedly, video is something else. The music I listen to doesn't have seat rumbling explosions, plane crashes, etc etc. In my old room I was actually content with the old UDL-12 and small Maggies. OTOH, I don't know what I was missing. And I know for sure that the MGIIIa's go much lower than the SMG's. At this point my inclination is to postpone the sub problem until the rest is set up as best I can manage. There's still a lot to figure out with room design and planar placement. Cheers,

In a panel speaker bass cut off is determined by the size of the panel.

Your speakers actually do not have an optimal bass performance. They have a significant lift between 60 and 80 Hz. (false bass) and the bass response falls off rapidly at 40 Hz, due to the panel dimensions. Their mid band response is superb and the HF quite good, but with a slight rise towards 16 KHz. So the speakers do not reproduce the last octave.

So the bottom line is that those speakers will sound much, much better with good subs, crossed at 80 Hz. That will get rid of the false bass and give you the last octave, which will improve music and HT.