[ctviggen]

In my quest to understand acoustics, I'm thinking of buying this:

http://www.rpginc.com/products/roomoptimizer/index.htm

It looks interesting and should be fun to play with.  Anyone use this?

[ScottMayo]

In my quest to understand acoustics, I'm thinking of buying this:

http://www.rpginc.com/products/roomoptimizer/index.htm

It looks interesting and should be fun to play with.  Anyone use this?

I haven't bought it, but I looked at it. The software doesn't understand pre-existing treatments; it always wants to start from scratch. If you already have tube traps and wantto add new things, that can be a bit of a limitation; but then, the price isn't bad. One other caveat: it doesn't seem to have been updated in awhile?

I expect to write one of these (one of those ongoing projects that's going to take a long time to finish). If you come across a more flexible version, let me know. I'm only writing one because I didn't find anything better for sale...

[ctviggen]

It might take you a while to write it.  I did some electromagnetism programs in my EE days, and the time to write the program was large.  And the program just spit out data that was unintelligible but to me.  The ability to solve these types of equations while also adding in features like couches, RPTVs, non-straight walls, etc. is probably why you don't see another program -- it's intractible.  For instance, in my room, I have two walls that come up so far then go outward, away from the room. I think you'd have to use an analytic technique to solve for the room interaction, and then resolve this for each placement of the speakers.  It could be a rough calculation.

[BradJudy]

I have been thinking of playing with something like this or CARA sometime (also under $100).  Has anyone tried both and can comment on their relative merits?

[Euterpe]

I use the Listening Room Program, to work on Early Reflections, Standing wave, ...

This soft  provided the ability to move the speakers and listener while viewing the boundary plot screen.

It run on DOS system, but on XP all is done.  

[ScottMayo]

It might take you a while to write it.  I did some electromagnetism programs in my EE days, and the time to write the program was large.  And the program just spit out data that was unintelligible but to me.  The ability to solve these types of equations while also adding in features like couches, RPTVs, non-straight walls, etc. is probably why you don't see another program -- it's intractible.

I did end up doing this. I used a raytrace approach, so I don't have to fret about odd room shapes - everything gets included automatically. It takes a while to run a simulation, though...

What it doesn't do, and might never do, is automatically solve the room for best possible placement of everything. I still end up looking at the output, positioning things, and rerunning. Maybe next year..

In the meantime, I think a dual processor 3Ghz system is in my future. This thing is a major number cruncher.

[warnerwh]

For 300 bucks including a microphone the Behringer DEQ 2496 will solve alot of problems.  My room is LEDE with bass traps but you still have room dimensions and other anomolies enter into the equation.  Let this piece do it's thing and then tweak it from there.  I will go so far as to say it's an absolute necessity and I will never go without one again.  With digital in and out you can even run a separate dac but the dac inside is an AKM 4393 and is a very good dac and sounds good too.  I know you guys have the money and once you see what this piece will do you're going to wonder why you spent so much time doing other things first.  At least that has been my experience these last two weeks.  It's like magic with no downside that I'm aware of.  

I've been in the hobby for over 30 years and DSP I believe is the wave of the future and the future is now.  If you buy it new you can return it in case you don't think it works as well as I claim.  Once you try it I have a feeling you guys won't go without one again.  

Just to be safe if you do decide to try one be sure to set the room curve yourself as you don't want a flat response in room. Also the amount of boost and cut can be set for both but not one or the other. I just let it go 6db and then brought down where the equalizer boosted to 6 db to  4 db just to be safe.

They do recommend you don't use it below 100 hz. So what I did is use a room calc program and notched down the theoretical room modes with the parametric equalizer.

[Brimsley]

For 300 bucks including a microphone the Behringer DEQ 2496 will solve alot of problems.  My room is LEDE with bass traps but you still have room dimensions and other anomolies enter into the equation.  Let this piece do it's thing and then tweak it from there.  I will go so far as to say it's an absolute necessity and I will never go without one again.  With digital in and out you can even run a separate dac but the dac inside is an AKM 4393 and is a very good dac and sounds good too.  I know you guys have ...

It seems that there was an incipient movement towards DSP about ten years ago and it sort of peetered out.  I saw a Meridian active system demoed back then and the Meridian representitive said they were working on getting a system to market involving altering the signal in the digital domain (which would necessitate that the crossover function occur in the digital domain) based on the results of a room sweep after the system was set up.  The ultimate goal was to have a system where the end user could do the sweep at the listening position and the system would optimize the output for the room.  Of course, there's only so much that signal correction can do to fix room anomolies by itself, especially in the lower ranges, but the idea made perfect sense to me.  Since the price of computing power does nothing but go down, it escapes me why this approach hasn't made more inroads.  There are probably engineering and/or market factors that explain it, and if anyone is aware of what they are I'd be interested in reading about them.

[jgubman]

Meridian has incorporated EQ'ing into their products:
http://www.meridian-audio.com/w_paper/Room_Correction_scr.pdf

So have a number or other pre/pro manufactuers like Lexicon, Denon, Pioneer, etc.

The Meridian solution doesn't alter the crossover, but it lets the user connect a SPL meter to the processor, run a room sweep and then it sets up EQ profiles (or lets the user customize the profiles). I have it and it works very well. Only covers frequencies below 250Hz.

[warnerwh]

This will no doubt become much more common and probably standard in even cheap HT receivers.  High power digital amps with digital crossovers built into speakers I'm guessing will also become popular.  One thing I know for sure is that if you're going after the best sound you can then DSP is a necessity in any room with a wall.  For the money the Behringer DEQ 2496 does so much good that I'd have to consider it the best bargain in my system.

[ScottMayo]

Of course, there's only so much that signal correction can do to fix room anomolies by itself, especially in the lower ranges, but the idea made perfect sense to me. Since the price of computing power does nothing but go down, it escapes me why this approach hasn't made more inroads. There are probably engineering and/or market factors that explain it, and if anyone is aware of what they are I'd be interested in reading about them....

I know my objection is that it's one more thing in the signal chain. There is always the worry that it's going to fix FR at the expense of something else.

My take on it is, fix the room first, because it's fairly cheap to do and can't possibly make the sound worse. If, when that's done, you still have FR problems, then it's time to bring in signal processing.

The other objection to signal compensation is that in a bad room, you can get the listening position fairly flat, but move a yard to the side and you get wild, sometimes unlistenable results. The worse the room, the more radical the compensations have to be to fix them, and the odder the effects are outside the corrected point. Fix the room itself, though, and most points in the room get better or remain the same; they don't generally get worse. Treating a large room isn't cheaper than signal processing and won't often get you perfectly flat, but in the end the room is friendly to be in, better for music over a wider area, and electronic treatments, if added, become more effective and less wild.

I have guests in both my living room and my sound room. My guests unanimously prefer the sound room - it's easier to talk in there, and even to hold multiple conversations in. It's acoustically polite space. It's to the point where I'm going to have to treat my living room, despite not having music in it.

[warnerwh]

I agree that treating the room first is mandatory. The fact still remains there's still many dips and peaks. Say you have a middle C of 440hz that's down 1 db. Then it's second harmonic is at 880hz that's up 3db and the next harmonid down 4 db.  Now what does a middle C sound like?  With digital in and out there's no downside I'm aware of.  It's a modern miracle to high end audio systems for 300 bucks.  Just taming the peaks and dips made a huge difference.  Combine that with the room treatment and the sound is pretty amazing.

Scott: Test the in room frequency response you have now.  At minimum you should at least try it. You can return it if you don't want one. Be sure to get the ECM 8000 microphone and let it do the room for you after you put in a room curve.  It will also do a room curve but I think it may actually dip the mid and high frequencies a tad too fast.  Then tweak with the parametric.  Even the dac is good in this piece.  

I held off for a long while thinking I'd need a good dac but the dac in this is very good.  It's three hundred bucks with a mike if you shop.  My personal opinion is that this piece or something like the Tact or DEQX units are a mandatory part of a\every high end system, especially to those people who can't have an acoustically treated room.  A better deal in audio I'm not aware of.

[Sintz]

It's a modern miracle to high end audio systems for 300 bucks.  Just taming the peaks and dips made a huge difference.

I couldn't agree more. I just picked up the Behringer DEQ2496 (with Behringer mic) for about $325 - shipped next day. I'm using the digital in from my CDP and the analog out from the Behringer (next step is to invest in a good quality DAC, maybe tube.

I have an 'L' shaped room with a stairway in the 'L' section. I've experimented with moving the listening location to all 4 orientations, and settled on the far end of the long part of the 'L', but was still left with difficult room nodes and strange reflections even after applying room treatments to the early reflection points and other "hot spots".

The addition of the DEQ2496 helped me get a baseline (using the auto EQ feature), then I've been tweaking for the past week or so, and finally have a balanced and deep soundstage that doesn't introduce listening fatigue.

Room treatments go a long way, but digital EQ'ing is a necessity for my room.

[jgubman]

I recently got a Velodyne SMS-1 to use w/ my two Largers.

Probably one of the easiest and most significant upgrades I've made to my bass ever...

[James Romeyn]

...Say you have a middle C of 440hz...

Or maybe a middle C of 261.630 Hz, or the A above middle C, which is 440.000 Hz?  Or so say my tuning forks...

OK, for everyone using digital room EQ: Let's say you have a great analog source, not master tapes, but similar qualities.  

1. Would you predict that the EQ's benefits would outweigh the downside of the added AD & DA conversions?  DAC quality is similar to or better than the Benchmark.  This room seems to be good above the bass range, but does have two severe bass modes, both of which are tamed electronically.

I'm very interested to hear your answers.  Reason being is I've been doing summersaults trying to figure out how to fix some room problems & avoid the two conversion processes.