[medium jim]

Well, as I said, it's what works for you. If you have the time to build and freedom to use traps, that's great, although IMO you still need EQ. I don't think anyone would argue that it isn't best to optimize the acoustics first.

Josh:

I would still argue that eq'ing first is the way to go, it is the most cost effective and renders the more for your money results in most instances.   Once you have flat lined your system or as close as you can with Eq, then you have a base to work with for the room acoustics and dealing with reflections, note decay, and room modes. 

One thing that hopefully all can agree on is that it is worthwhile to take some measurements of what your system is doing, old school as I have done or by modern more sophisticated methods.  If the room is really out of wack and there is a bunch of things wrong, well then to the room first, but we're talking about Planars that basically will only perform their best in the listening position no matter how or by what method you set them up. 

As you already stated, MMG's in their stock carnation will typically have a dip at 100-200hz, (mid bass), this may have been addressed with the mod's that Rclark's MMG have undergone.  This still means that most likely in the lower octaves there will be some funkiness that merely going with high-passing will alleviate and allow for a smoother integration and isn't at all expensive.  If one opts for a digital EQ room correction setup, still in most instances under $500.00.   IMO, more results for the money than treating the room...it can get real expensive treating a room in many cases, even if DIY. 

I'm not saying not to treat the room, rather do what will yield the greatest return initially (unless money is no object).  Understand, the main focus of treating the room is to tune the room and the main reason to eq is to tune the system.  Go on other forums and this issue has been debated ad nauseum with valid arguments for both approaches.   To say one was wrong was ludacris.

Jim

[medium jim]

One more thought, the Epik Legend is most likely 8ohm and its low pass is based for 8ohm. Magnepan MMG's are 4ohm...

Jim

[Rclark]

Josh as much as I hate to say it, I looked at several units just now, and a 3 out Velodyne sub controller for $499, but this Behringer looks awfully advanced for about $350

http://www.behringer.com/EN/Products/DCX2496.aspx

and the Ultra Drive has six outputs so I don't have to do any y-splitting and can go as high as six subwoofers in the future if I have a larger space. I like that it's manual control. Time alignment, PC controlled, I think that's the one.

Thanks for the offer on the microphone, but I'm just afraid I would screw REW up, or that it just wouldn't work somehow with firmware this and update driver that and calibrate this...

 Think I'm going to go with the XTZ package when I'm ready.

[jtwrace]

Josh as much as I hate to say it, I looked at several units just now, and a 3 out Velodyne sub controller for $499, but this Behringer looks awfully advanced for about $350

http://www.behringer.com/EN/Products/DCX2496.aspx

and the Ultra Drive has six outputs so I don't have to do any y-splitting and can go as high as six subwoofers in the future if I have a larger space. I like that it's manual control.

Thanks for the offer on the microphone, but I'm just afraid I would screw REW up, or that it just wouldn't work somehow with firmware this and update driver that and calibrate this...

 Think I'm going to go with the XTZ package when I'm ready.

Many use the DCX.  It works well when it works.  I'm on my second one and look forward to the DLCP for this reason.  The DCX controls my 4 subs.

HolmImpulse is by the far most consistent program that actually works every time.  REW is great but is buggy.

[Rclark]

So they crap out?

[Rclark]

I think I'll try one, I can always go back to one sub if it ever needed to be serviced.

[jtwrace]

So they crap out?

Yep.

I think I'll try one, I can always go back to one sub if it ever needed to be serviced.

GL wtih service.

[Rclark]

 Sweetwater has them with a two year warranty. Unfortunately I don't see any other options that can control more than 3 subs, let alone for that money, without using splitters. I'd rather have individual control.

 Two years outta be enough time to learn how to use it + measurement rig and get my room fully treated and dialed out and then move up to what Hypex will have.

 I'd rather use something else, but seems to be the best option for multiple subs.

[medium jim]

Sweetwater has them with a two year warranty. Unfortunately I don't see any other options that can control more than 3 subs, let alone for that money, without using splitters. I'd rather have individual control.

 Two years outta be enough time to learn how to use it + measurement rig and get my room fully treated and dialed out and then move up to what Hypex will have.

 I'd rather use something else, but seems to be the best option for multiple subs.

Very interesting, you will be fixing the eq first!

Jim

[TNRabbit]

One more thought, the Epik Legend is most likely 8ohm and its low pass is based for 8ohm. Magnepan MMG's are 4ohm...

Jim

I was reading about this misunderstanding on another Epik thread.  The impedance of the final speaker has NOTHING to do with the crossover point which occurs back in the pre stage.  Your argument is that the impedance changes the crossover point, but that doesn't make any sense.

[jk@home]

Sweetwater has them with a two year warranty. Unfortunately I don't see any other options that can control more than 3 subs, let alone for that money, without using splitters. I'd rather have individual control.

 Two years outta be enough time to learn how to use it + measurement rig and get my room fully treated and dialed out and then move up to what Hypex will have.

 I'd rather use something else, but seems to be the best option for multiple subs.

I own quite a few of the Behringer pieces, some bought used, some new. Fingers crossed, none have failed me yet.

The DCX is an excellent unit, the only major complaints is the D/A and A/D converters are not "high end", and work best with the higher level "pro audio" signals. But there are folks out there who offer mods for this, so you could go there is desired. For regular consumer stuff, I've gotten the best performance from mine using the digital input, too bad it doesn't also have digital outputs.

One neat feature is you can download the remote PC control from the Behringer web site, on to a laptop or PC, run a cable from that to the DCX, and control and adjust it "on the fly" from the computer.

Another piece I have recently added was replacing a Monarchy DIP2496 for a Behringer SRC2496. I originally just added it as a "digital switcher", but I swear the resolution of the system went up, must be that upsampling thing.

[Rclark]

Thanks! I have my order finger ready. Someone suggested Amazon with their extra charge warranty but I like Sweetwater's higher price with automatic warrantee, plus I am dealing with a company that deals strictly in this stuff. Just waiting for them to get their next shipment in and I'm doing it.

Also, loving this sub more and more every day, it's now an integral part of my Maggie system and more of these are definitely in the que. They do everything right including spectacular hit-you-in-the-chest midbass that blends seamlessly.

[jk@home]

Just make sure you do your research on how you are going to setup the DCX in your system, as it is not "plug and play" in regards to use with standard consumer products, it's designed for the pro audio field. Here's one link of many on the web.

http://www.diyaudio.com/forums/digital-line-level/15943-behringer-dcx2496-digital-x-over.html

[Rclark]

thank you very much, yeah I'm quite ready for the learning experience. I'm going to add either an Omnimic or XTZ Pro II (probably that one) and learn how to fine tune everything.

I'm going to try to mimic exactly the sub crossover I have now for the time being.

[Davey]

Actually, it's a perfect example of plug-and-play.......you'll be playing with it constantly trying to understand the operation, avoid the many pitfalls, implement a system volume control correctly, avoid noise, etc, etc. 

For this type of implementation it's complete overkill.  But I understand the attraction a gadget like this has. 

Dave.

[Rclark]

 Well I was going get a simpler device, but several people recommended this, and I do like the time alignment. This way I can truly have the subs in their optimal spots.

[jk@home]

Actually, it's a perfect example of plug-and-play....... 

Dave.

LOL. That's funny (and true).

[Rclark]

Oh wait stop the press. How about just using one of these instead.. for everything?  CDP as transport into this all by itself and call it a complete system:

http://www.dspeaker.com/en/products/20-dual-core.shtml


a "swiss army knife"

http://www.avforums.com/reviews/DSpeaker-Anti-Mode-8033-Dual-Core-review_361/Review.html


 Oh wow, it can even be run from a 12V battery supply. Wow. I'll just unplug my Warpspeed and plug this right in, I already have 12V and charger up and running.

 Unless someone convinces me that this is a horrendous idea, I get my Ncores in a week and a half, and then next month this is my next purchase and other than one or two more Legends, I'm guessing my system will be 100% complete at that point and pretty top-spec, or near that, on all fronts, an ultimate 7-8K system (need to tally it all up). Not too bad for a first hifi. We'll see.

 Rodge827 has one and loves it. I am prematurely excited but all my hunches have been home runs.

[bdp24]

Yeah, they're definitely "sweet spot" speakers, not great for partying. However, the fact that they dump 4.6 dB (IIRC) less sound into the room is one of the reasons they sound better. It's also easier on the neighbors. If I could have the ideal front channel speaker, it would be even more directional. I'm convinced at this point that room reflections are the largest problem in sound reproduction.

. That reminds me of the worst speakers I ever owned---Bose 901's, in 1970. 8/9th's reflected sound! I now have as directional a speaker as has ever been available, the original Quad ESL's. I got a bunch of the original bass traps ($10 apiece in The Recycler. A couple of 15's, some 12's, some smaller ones---a room full for $120!). I'm now making some directional OB subs, 2 GR 12's in each W-frame. Oughta work great with the Quads.

[James Romeyn]

While a multiple sub strategy with a mono signal can give you smoother bass by cancelling some of the room modes, most seem to prefer stereo subs for music listening, because bass is so important to a sense of ambiance and space.

In truth, I'm not sure why this is, given that most recordings have mono bass. But it's what people say. Maybe it has to do with the slope of the low pass filter -- a sub will typically still be making a contribution to the sound up into the midbass or even lower midrange. Harmonic distortion could also play a role. Woofers make a lot of it, and it isn't going to be affected by the LPF.

My distributed multiple sub low pass pole is 4th order around 65 Hz increasing to 6th order @ 80 Hz (active HP pole is 2nd order @ 80 Hz).  C3 is 131 Hz, the C below middle C.  Listen to that note.  If your sub contributes substantial energy at that frequency I tend to bet that's a problem that must be fixed.   

Speed of sound 1130 fps/70 Hz = 16.1 foot wavelength.  Under what circumstances can a microphone or human ear perceive stereo wavelengths 16 feet long in a listening room of normal domestic proportions?  Start with measuring the distance between the L/R speakers, which in most cases is less than 16 feet.  The lower the frequency the less audible is stereo effect (but we're already starting with inaudible at 70 Hz).     

Boundaries shorter than 16 feet require the wave to reflect from one boundary to another prior to being perceived.  This means the boundary is permanently and indelibly imprinted prior to perception.  It also means EQ only helps in one location in three dimensional space, and it also means it simultaneously makes performance worse in other locations.  FR problems are bad enough.  But even worse are timing problems resulting from modes.  Modes can and do cause bass notes to linger after the speaker stops reproducing the note, in fact, one note can and often does continue to resonate after the next bass note is struck.  So this results in two disharmonious notes sounding simultaneously where should be one note.  This is infinitely worse and more audibly offensive than mere FR peaks and valleys.  This is two bass players, one playing the wrong note while the other plays the right note.  You need to be a musician to understand the impact.  This explains why some/many persons prefer smaller speaker with less bass power and higher bass cutoff.  Because at least the bass that it has is reproduced more accurately.     

EQ can and sometimes does help FR but does not improve timing errors resulting from the boundary effects (modes).  It can take multiple thousands of watts to correct for certain FR dips.

Beyond modal effects, the average domestic space boosts the range below 100 Hz by about 3 dB/octave.  This being the case, a perfectly flat reproducer below 100 Hz measures about +7 dB @ 20 Hz (separate from modal effects).  Listeners often like sealed bass because it's roll off rate more closely approximates the inverse of the room gain described above.  One item against reflex subs is that occasionally the port is tuned equal to a mode peak, which exacerbates the mode, the bump, and timing error (dreaded one note bass).   This can't happen with a sealed sub.

I don't have link to the following, sorry.  Someone I'd rather not mention told me, and I tend to believe, humans have extremely high tolerance and extremely low sensitivity to THD in the bass range...to the tune of hearing no difference between the typical 5% at moderate levels (I estimate a decent high end cone speaker makes 5% THD around 35 Hz @ moderate levels, some much higher) and 30+%.  Yes, thirty percent distortion may be inaudible to humans in the bass range.  But getting back to the timing errors I mentioned earlier, even if one is oblivious to 30% THD, if/when two incorrect and disharmonious notes play from modal effects, the result is not tens of percent but rather hundreds of percent "harmonic" distortion.  That's why timing errors from modes dominate in the bass, not FR, and not normal THD.     

Obviously in the mid range, with frequencies close to the ear spacing in our head, the tables are turned, where we can blindfolded tell the trajectory of a coin turning on its edge and where ear sensitivity to many distortions is at its highest.

John Krutke of Zaph Audio states on his website that large FR swings (forgot, +/- several dB) are to be ignored in the very top octave because the ear has low sensitivity in that range.

The meat appears to be right in that classic range old speaker designers always said to avoid a crossover, 750-3k Hz.

Over the years I've heard several ultra high end sub towers, enclosures from floor almost to ceiling, and filled with four to six woofers, usually 12s, occasionally 10s.  In every case I heard audibly superior bass and better than any normal single column full range speaker.  Till I discovered proper distributed array these huge towers were my very favorite bass reproducers. 

I used to think these huge tower subs were better because you can barely see the woofers move, and hence this alone proves their distortion is tiny fractions of mortal bass reproducers.

I'm now convinced it was not about THD, but more about the fact that such sub towers largely eliminate the worst mode (floor to ceiling) and they are so large that their physical presence in the room damps other modal effects.