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Digital Room Correction: The Final Frontier?

Like most of you, I've been experimenting with different room treatments, and various other tweaks (footers, power conditioners and cables, interconnects, etc.) for many years trying to optimize my ever changing system.

I've enjoyed my system immensely, but I knew I had some speaker/room problems, and I was growing increasingly tired of listening to an over-ripe lower midrange, a boomy lower bass (even with the speakers 6-7' into the room) and a rolled-off upper-mid/lower treble on my Talon Khorus (and before that similar problems with my Genesis V and ProAC 3.5).

So I attacked my room. I put bass busters in the corners, Roomtunes along the ceiling borders, a thick 12'x15' Oriental carpet, and at one point last year had (count 'em) eight Roomlenses in my room. It all helped.

I tried several different amps, finally settling on a Gamut D200, which helped ameliorate the ripe mids and tightened/lightened the lower bass, aided by a switch to Nordost Quattro-fil ICs and Wireworld Silver Eclipse lll cables (after trying at least 15 cables).

Added an Audiomagic Stealth along with BMI Shark/ EG Fatman PCs. Used Bright Star Gemini sandbox/innertube. Floated the speakers and digital with Aurios. Again, it all helped. Some.

Finally, after hearing one in a friend's system, and being quite impressed, last week I installed a Tact 2.2x in my system. I'll post a review after I've had more time experimenting with it, but I'm flabbergasted.

First, I was both horrified and reassured by the uncorrected room measurements. Horrified to see a 10dB peak at 28Hz, along with a huge rise in the mids and steep drops in the upper-mid/ lower treble. Reassured because that's what I was hearing, and now I could see it on a graph.

Surprised, because I had thought my dedicated room was a reasonable size for audio (16'x24'x10'). Surprised that after such careful speaker placement and measurements, one speaker reached my ears so much before the other.

Surprised to find that all those other tweaks I thought were so helpful, were so minor compared to what the Tact 2.2x can do. I can even-out the frequency response, time align the speakers and clean up the mids and bass with a simple push of a button (well, after some serious mouse work); all with a minimum cost in other areas.

Going back to bypass mode, my speakers now sound like I threw a blanket over them.

More to come....
richards
onhwy61's avatar
onhwy61
5,218 posts
 
The TACT is a very powerful tool and is capable of producing wonderful results. On the downside it's only appropriate for digital only systems and the software is complex with skimpy documentation. I've been using a TACT for about a year with very positive results. You still need to pay careful attention to speaker placement and room treatments, but the measurement capabilities of the TACT bring some rigor to the process. I recommend removing all room treatments and then adding them back one at a time and measuring. Also the system is very sensitive to the microphone's orientation and placement during the measurment stage.

Their is a TACT user group that you might find useful.
rives
953 posts
 
Of course, it's good when we don't have to correct rooms electrically but can do it passively--this can be almost impossible in the bass region. I'm not at all surprised as to your findings--I only wish you had found our company first. We are an acoustical engineering company that designs listening rooms, but recognized this issue and we were not satisified with any of the devices on the market. We make a PARC device designed specifically to deal with the bass mode problems. When we designed it I was very concerned about signal purity and having a degree and graduate work in digital signal processing I knew that I wanted to stay in the analog domain. Part of this was due to my love for vinyl and upcoming formats that might be degraded in the digital domain, but part of it was just a characteristic nature of running the signal back through an A/D and D/A converter. So we designed a 3 band parametric notch filter system that has a range of 16 to 350 Hz, Q factors of 1 to 11, and attenuation up to 18 db. I don't think any other unit has anywhere close to that head room. It's digitally controlled but the audio signal remains solely in the analog domain. The unit is calibrated using proprietary software that has a psycho acoustical response filter (it reacts similarly to the human ear in terms of gating times at different frequencies.) You can also calibrate the unit in a manual method with test tones, but this is more time consuming and not as accurate. It also doesn't have the advantage of being able to see the graphed results in near real time.

The other thing that is very interesting is that you have Talon speakers. We used the PARC at CES on a pair of Talon's new Firebird speakers. Mike Farnsworth, president of Talon, was delighted with the sound and told me he wants the PARC at all shows. He had not been happy with any other correction system he had tried in the past. We will be with Talon again at HE 2003. For more info on the PARC.

Obviously, I'm clearly biased here. I do believe we designed an incredible product that sounds better than anything else that corrects for room modes, with excellent build quality using connectors like WBT and Neutrik. But perhaps more impressive was making this device at a more affordable level.
newbee
4,767 posts
 
Rives, In the past your posts seemed to be helpful and responsive to inquiries. In this case it seems that its just advertising and meant as much for the consumption of other readers as for the original poster. It appears from the posters comments that he has little understanding of standing waves caused by room dimensions and how one can avoid them passively, or at least lessen them substantially. You could at least have referred him to your web site wherein you have a good discussion about the problem and provide evaluative tools for proper placement of speakers and listening positions (at least for starting points). Incidentially, after I looked at your site, i checked my speakers and they were within 1" of your suggested location - the listening position was not as close.
rives
953 posts
 
Newbee--was that on the simulator you are referring to? It does a pretty good job and is really designed to flatten the frequencies as much as possible below 500 Hz. Above that number you may have notice very little changes. As to your other comments, I appreciate those and was worried about that a little. I should have pointed out the listening room, which is a tutorial and describes more about bass modes and also has a simultor (which is what I think you were referring to on the speaker and listener placement issue).

Anyway, I do want people to know about the product we've developed--and I think my enthusiasm for what we've done didn't really come across as such--but as you said more advertising. That was not the intent, but I certainly understand your point.
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duddley
78 posts
 
Rives,
Does your product address time alignment issues ala Tact? How do you avoid injecting phase incoherence when performing analog eq? I, too, have been eying the Tact systems, however, they are expensive, and I am not looking to add another D/A or A/D in the signal chain.
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