Target Curves

[audioguy]

When is flat not exactly flat?

On another thread, I showed some charts of the Audyssey Sub EQ product on my four subs. After correction, it generated (as it is supposed to do) a ruler f;at response (as measured and corrected from 15 different positions.

The before and after SubEQ response is shown below:



One would think (but apparently one would be very incorrect) that if you ran a TAcT test signal through the filter created in the SubEQ that something representing a flat line should be the result.

Check this out:


That is a huge drop from 80hz to 10hz. I need to run REW or (soon) XTZ through the Audyssey SubEQ to see what IT thinks flat looks like.

Wierd!!

[audioguy]

I have been running my TacT using the two subs on the left of the room as the left sub and the two on the right as the right sub (even though I'm crossing over at 65hz so there really is no left or right). In doing it this way, I was taking advantage of the smoothed response of the front and rear subs combined but was NOT adjusting for the difference in distance between the front and rear sub. Running it through the Audyssey addresses that issue.

Only one small problem: It sounds much cleaner the original way.

The issue for me is if I keep it this way I have to reconnect my subs when switching from 2 channel to HT.

I tried to find a switching product that would allow 4 in and 4 out so that I could automatically connect any of the sub inputs (2 from the Onkyo or 2 from the TacT) into any of the 4 sub outputs. QSC has oe but it has an MSRP of $3700 so I will pass on that solution.

[RUR]

When is flat not exactly flat?

On another thread, I showed some charts of the Audyssey Sub EQ product on my four subs. After correction, it generated (as it is supposed to do) a ruler f;at response (as measured and corrected from 15 different positions.

The before and after SubEQ response is shown below:

Chuck, what are the scales, especially what's the lowest frequency shown? Can't be 0Hz.

One would think (but apparently one would be very incorrect) that if you ran a TAcT test signal through the filter created in the SubEQ that something representing a flat line should be the result.
*snip*
That is a huge drop from 80hz to 10hz. I need to run REW or (soon) XTZ through the Audyssey SubEQ to see what IT thinks flat looks like.

An REW measurement would be very helpful. Don't forget you're comparing a 15 measurement, averaged plot (Audyssey) with a single measurement plot (TacT). Also, we need the scale answer from above. Also also, does Audyssey show 1/3 octave smoothing? 1/6 octave? Something else? (I'm not an Audyssey expert, by a long shot.....) Basically, we need to find out if we're comparing apples and ducks before we figure out anything else.

I have been running my TacT using the two subs on the left of the room as the left sub and the two on the right as the right sub (even though I'm crossing over at 65hz so there really is no left or right). In doing it this way, I was taking advantage of the smoothed response of the front and rear subs combined but was NOT adjusting for the difference in distance between the front and rear sub. Running it through the Audyssey addresses that issue.

Only one small problem: It sounds much cleaner the original way.

OK, slowly for the slow guy... Running correction thru Audyssey Bass(?) adjusts the distance for all four subs? If so, are you allowing the TacT to measure and set sub distance? If so, try turning that off, so that TacT isn't trying to correct the corrected distances.

What do you mean when you say "the original way"?

[audioguy]

There are no scales on the Audyssey curves but one could assume (by counting vertical scale lines), that the low end is 20hz. Audyssey won't comment on exactly how the curve is plotted. I'm not really concerend about how smooth the Audyssey curve is only the general slope relative to the general slope of the Tact Curve. Because the Tact sees the negative slope, it is creating a filter with a large boost at the bottom end. The chart below show the uncorrected response the TacT sees when I have things connected the "original way" excluding the Audyssey SubEQ.

The "original way" was the left front and rear sub were assigned to the TacT left sub output and the right front and rear sub were assigned to the right TacT sub out.

The Audyssey SubEQ has the time delays of the rear subs taken into consideration but no delay with respect to any other speakers.

The attached chart is the rigth two subs, no correction and no delay of the rear subs.

[Robh3606]

Here is a Harman Synthesis Curve. You might want too add it too the colection,

Rob

[RUR]

Looks similar to a number of available curves in the TacT database. If I can't find a match with an existing .cor file, I'll create one and post it here for TacT owners to try.

and welcome to the forum! :-)

[audioguy]

I have a similar curve but mine goes south at about 10Hz. I'll try this as well.

[Phelonious Ponk]

This TACT piece in question...is it a digital preamp? I feel like the Joker, in Batman..."Where does he get all those wonderful toys?'

I want an iTunes plug in with a much more granular graphic eq and a parametric as well. I know, degradation from bit perfect and all of that...don't hear it, but I do hear a 2 db lift at 80 hz to give more body to low volume listening. This toy you boys have looks like a wonderful tool.

P

[RUR]

This TACT piece in question...is it a digital preamp? I feel like the Joker, in Batman..."Where does he get all those wonderful toys?'

I want an iTunes plug in with a much more granular graphic eq and a parametric as well. I know, degradation from bit perfect and all of that...don't hear it, but I do hear a 2 db lift at 80 hz to give more body to low volume listening. This toy you boys have looks like a wonderful tool.

P

Tim, the bit of gear most/all of us are using is, indeed, a digital preamp - the TacT 2.2XP. It provides room correction for two mains and two sub-woofer channels, and configurable active crossover between mains/subs. The same RC is also available in other TacT gear, including (as an option) their digital amplifiers.

Parametric EQ is also provided, as well as "Dynamic Room Correction" using configurable Fletcher Munson curves. It is a wonderful tool. Their website is here, and I'd be happy to answer any specific questions you may have.

[RUR]

Tim, a couple of other observations now that I'm properly caffeinated... The TacT will provide adjustments as small as 0.8Hz and 0.1 dB. How much more granular are you seeking? I think most folks would be surprised by how small a change in level is noticeable. 2dB is actually very easy to hear and I'd swear I often hear adjustments of 0.1-0.2dB.

(((acourate)))® is a Win XP solution, and supports "Intel Macs with XP".