TacT Questions

[bootman]

Dec 12, 2012 17:52:31 GMT -5 urwi said:

On the ther hand we have two ears and not just one.

Very true and no two ears/brains are alike.
However your comment did spark an interesting idea.
Imagine a pair of headphones that aren't headphones at all but stereo mics for RC measurement.

It would virtually guarantee correct mike placement with regards to seating position.

[iketremonti8]

Dec 12, 2012 17:52:31 GMT -5 urwi said:

Dec 12, 2012 17:17:29 GMT -5 iketremonti8 said:

I'm no audio engineer, but just in my feeble mind using logic, it's impossible to optimize the audio for multiple seating positions. The response of the room changes depending on your location in the room. You can take multiple measurements and maybe end up with the best compromise between all of those seating positions, but it will never be fully optimized for any one seat. I believe that's why Boz says its just a marketing ploy basically. By measuring multiple positions you are only adding data to the mix that will ultimately degrade the optimum response from the main seating position, so what's the point? Maybe someone wiser and smarter can correct me. Just figured I'd toss that out there.

On the ther hand we have two ears and not just one.

lol, true. But those 2 ears are always at one seating position at a time acting together. Again, I'm no engineer, but I can definitely see why multiple measurements from different points in the room is a waste of time.

[billmac]

Dec 12, 2012 17:17:29 GMT -5 iketremonti8 said:

I'm no audio engineer, but just in my feeble mind using logic, it's impossible to optimize the audio for multiple seating positions. The response of the room changes depending on your location in the room. You can take multiple measurements and maybe end up with the best compromise between all of those seating positions, but it will never be fully optimized for any one seat. I believe that's why Boz says its just a marketing ploy basically. By measuring multiple positions you are only adding data to the mix that will ultimately degrade the optimum response from the main seating position, so what's the point? Maybe someone wiser and smarter can correct me. Just figured I'd toss that out there.

You could very well be correct. But as you mention you're not an audio engineer and I'm certainly not one either . My point was why not stress what Boz' feels are the positives of TacT without claiming other RC systems that use multiple measurements as "marketing hype and not the science of sound". I don't see the staff from Emotiva slamming their competitors in this way.

Bill

[monkumonku]

Dec 12, 2012 18:05:56 GMT -5 iketremonti8 said:

Dec 12, 2012 17:52:31 GMT -5 urwi said:

On the ther hand we have two ears and not just one.

lol, true. But those 2 ears are always at one seating position at a time acting together. Again, I'm no engineer, but I can definitely see why multiple measurements from different points in the room is a waste of time.

On top of that, unless you have a really big head would it make that much difference to use two mics versus one? ;D Then you'd also have to take into account the shape of people's ears and their heads, too.

Also, do you sit in the EXACT same position every time you listen? Because if you don't, then the variance between where you sit for session A and session B is probably larger than the difference in distance between your ears.

I think we are more critical when listening to music, and generally whereas there may be several people in a room watching a movie, most people listen to music by themselves. So it seems more valid to me to choose that preferred listening position as also the position at which to place a mic and optimize the results based on that position.

Unless you are having a GTG with a bunch of people listening critically, if you have several people in a room just listening to music then sooner or later someone is probably going to start talking and people won't be listening as intently to the music.

[billmac]

Dec 12, 2012 18:05:56 GMT -5 iketremonti8 said:

lol, true. But those 2 ears are always at one seating position at a time acting together. Again, I'm no engineer, but I can definitely see why multiple measurements from different points in the room is a waste of time.

So RC systems like Audyssey (including Pro) and ARC (Anthem Room Correction) are a waste of time? Have you heard these RC systems and have experience using them? For not being an audio engineer it is a pretty bold statement to say these RC systems are a waste of time .

Bill

[klinemj]

Regarding Dr. Boz's statements, I am also not an audio/acoustics engineer, but his statements made sense to based on physics of a wave - at least within what I would consider "reasonable" seating positions. Why, you say?

From a single position, a mic would measure all wave forms coming to it. If the wave form came directly forward, in a straight line from a speaker (impossible, but hang with me here...), the mic would measure what got to it and it would be straightforward to calculate what time it should have taken and other aspects. Now, if that same wave went off both the left and right speakers each at a 45 degree angle to the speaker, hit a respective wall on each side - the wave would be (in part) bounced back to the mic's position - different data would be recorded. If it's more complex in reality - as it always is...different data would be recorded.

In any case, if I take the data from either the 1st or 2nd relatively situation and say, "theoretically, what would I have recorded from a perfectly centered mic vs. one that is, for example, 2 feet off center to the left"...the answer would be that this is fully predictable from basic physics of sound waves. So, if one knows the result from 1 position - one knows the result from all.

The only assumption this makes is "reasonable seating positions". For example, if one had a couch in front of the system - dead center in the middle...seating in the center, left, and right would yield different results, but the result of each would be, from physics, predictable from one measure. Now...if one knealt on the floor behind the couch with one's head under a rug...no.

Now, for the more complex situation (reality, with waves bouncing everywhere) - all that i said for the simple situation is true, but the data is more complex. But, each position is predictable from another.

Bottom line, based on what I studied in physics on waves (2 years in high school, 2 years at Purdue) and their predictability - I tend to lean w/Dr. Boz's comments. And, he's got far more data than me on which to base his statements.

And by the way to Billmac...I didn't take the way he said it to be "bashing" others. He was simply stating his opinion based on his data - which to me, aligns soundly (no pun intended) in wave theory.

I can also understand why, on the surface, measuring multiple places sounds like a good idea. But, if one thinks of it as Dr. Boz explained it in terms of basic physics of waves...his argument holds water with me.

Mark

[jamrock]

I'm no engineer either. But my limited understanding tells me that unless your system is interactive (changes room frequency as you change positions) no particular seating position will be fully optimized. Every position is compromised to compensate for the other. Since the audio is radiating from 1 position in the room, the room frequency will change as you change positions. But if you measure from 1 position, you will have a reference of how to compensate for other likely positions to make them sound like the main seating position. You simply cannot have several main seating positions for the same room in relation to the speakers.

[billmac]

Dec 12, 2012 18:24:04 GMT -5 klinemj said:

And by the way to Billmac...I didn't take the way he said it to be "bashing" others. He was simply stating his opinion based on his data - which to me, aligns soundly (no pun intended) in wave theory.

I would think that his opinions and data would more than likely favor TacT . Did Boz mention if he has hands on experience with other types of RC systems that use multiple measurements? I guess we could debate this quite a bit but till TacT is up and running in the XMC-1 it will not be known how good it is. Another question is if TacT and its calibration process is superior to all other RC systems why didn't TacT catch on as other RC systems have?

Bill

[bootman]

Dec 12, 2012 18:47:22 GMT -5 billmac said:

I would think that his opinions and data would more than likely favor TacT . Did Boz mention if he has hands on experience with other types of RC systems that use multiple measurements? I guess we could debate this quite a bit but till TacT is up and running in the XMC-1 it will not be known how good it is. Another question is if TacT and its calibration process is superior to all other RC systems why didn't TacT catch on as other RC systems have?

Bill

That one is easy.

Economics.

The stand alone TacT systems were expensive compared to what Audyssey cost in mass market gear.

[billmac]

Dec 12, 2012 18:52:43 GMT -5 bootman said:

That one is easy.

Economics.

The stand alone TacT systems were expensive compared to what Audyssey cost in mass market gear.

Stand alone Audyssey systems were around $2500 which is fairly expensive as well. Maybe TacT should have done what Audyssey did and license their technology to AVR/prepro manufacturers. Then TacT would have made a ton of money and their technology would have been available at an affordable cost as Audyssey is. Similar to what Trinnov did with Sherwood. Which is basically what I believe TacT is now doing with Emotiva. Or did Emotiva buy the rights to the TacT technology?

Bill

[Deleted]

The TacT systems we sold back in the day were 2-channel only and cost upwards of $12,000. That alone explains why they are not more "popular"...

-RW-

[Deleted]

"Which is basically what I believe TacT is now doing with Emotiva. Or did Emotiva buy the rights to the TacT technology? "

My guess, and it surely is a guess, is that TacT wants to break into the HT/Surround Sound market and Emo is providing them with a testbed (and funding) for this. This version of TacT is licensed only to Emo. I'm betting they take what they learn from this and will then "chip-ify" it for licensing to other mfgrs....

-RW-

[billmac]

Dec 12, 2012 19:08:44 GMT -5 @rlw said:

The TacT systems we sold back in the day were 2-channel only and cost upwards of $12,000. That alone explains why they are not more "popular"...

Then one would think that in order to be more successful one would have to lower their prices .

Dec 12, 2012 19:12:03 GMT -5 @rlw said:

My guess, and it surely is a guess, is that TacT wants to break into the HT/Surround Sound market and Emo is providing them with a testbed (and funding) for this. This version of TacT is licensed only to Emo. I'm betting they take what they learn from this and will then "chip-ify" it for licensing to other mfgrs....

I would say it would be a good guess . If Emotiva is funding this then maybe they will get a percentage of the licensing if TacT does sell to other manufactures.

Bill

[geebo]

Well, I'm no engineer either.

[klinemj]

Did Boz mention if he has hands on experience with other types of RC systems that use multiple measurements?

Actually - yes, he did mention that. And, he said that he was going down the path of multiple measurement sites when he realized the fundamentals & saw proof of them in correlations of results. And that is what led him to the approach he implemented w/TacT.

Also, independent of his data, his hypothesis agrees w/physics of sound waves, so - that's pretty hard for me to say is wrong.

But bill - you are correct in that we will have to wait and hear the XMC implementation to see how good it is. I do look forward to it - it stands to be a large jump vs. EmoQ v1 (and even v2).

Mark

[billmac]

Dec 12, 2012 20:55:18 GMT -5 klinemj said:

Actually - yes, he did mention that. And, he said that he was going down the path of multiple measurement sites when he realized the fundamentals & saw proof of them in correlations of results. And that is what led him to the approach he implemented w/TacT.

Also, independent of his data, his hypothesis agrees w/physics of sound waves, so - that's pretty hard for me to say is wrong.

But bill - you are correct in that we will have to wait and hear the XMC implementation to see how good it is. I do look forward to it - it stands to be a large jump vs. EmoQ v1 (and even v2).

Mark

Thats cool . I wonder if the other RC companies took a look at TacT as well? It would be interesting if all these companies keep a close eye on each other.

I look forward to the release of the XMC-1 as well. I'm hoping that TacT is all that it has been said to be and then some. I have my upgrade card ready for when that time comes .

Bill

[klinemj]

I'd bet other companies have looked at it. And, based on the theories behind it, and how they have implemented it in the stand-alone systems - I am really excited to give it a try in the XMC. I was totally stunned at what it did for the system they demo'd at Emofest (which was not the version that would be in the XMC-1). From a pure theory POV, it had this techno-nerd drooling...and the impact was great, too!

Kudos to Dan and company for working out the partnership they did.

[Tip]

Dec 12, 2012 9:26:25 GMT -5 bootman said:

I have read that TacT only needs one measuring point to do its magic while competing products use several.
Since the common conception is that more is better, why in this case would less be more?

RCS systems like Audyssey take measurements at multiple locations so that it can create a larger, although less effective, sweet spot for the benefit of several listeners. RCS systems like RoomPerfect take multiple measurements, first at the prime listening position and then all over the room (at non-listening positions) to gain what it calls "room knowledge". RoomPerfect is then able to discern the room acoustics and separate them from the speaker response at the prime listening position. So it knows what it can correct and what it can't.

[Tip]

Dec 12, 2012 10:29:55 GMT -5 Jim said:

If this is a fair place for "newbie" questions. For measuring response/room, does TacT do sweeps (pings, etc) similar to Audyssey?

TacT uses pulses to measure. (Actually it uses three pulses, one for the low frequencies, one for the middle frequencies, and the last for the high frequencies. These are then analyzed with shorter and shorter time windowing of the responses.) The impulse response can be converted to the frequency response, like a sweep, and a step response through FFT processing, just as a sweep can be converted to the other responses though FFT processing. To paraphrase Bill Clinton, it's just math!

[Tip]

Dec 12, 2012 12:34:19 GMT -5 wizardofoz said:

I would like to know how well it will work for stereo 2.0/2.1/2.2 setups and if it can support setups for different modes like 5.1 or 7.1 and still have a different setup for 2.x

Also can it support setups for say 2 different rooms...i might have a fully bal setup in one room but rca in another room but just use the triggers to select one or the other amps...gear is all in one room

It depends on how Emotiva implements TacT. The TacT processors have nine correction presets that can be selected for different target responses. The TacT TCS has a "mixer" function that allows any combination of satellite or sub correction of its 12 output channels. If you have a long enough mic cable, you could also have correction for two rooms at the same time. But I doubt the XMC-1 will have room correction for Zones 2 and 3.