[cfraser]

I have noticed when running Audyssey MultEQXT that it always detects my sub as being much closer than in reality. It gets detected as 6.5' away, when in reality it's more like 11'. I have not got any good reason why this should be so, so just wondering what others may have found. Checked with LFE input (level control doesn't affect this), phase at 0, LPFs at 250Hz (max.), sub 10" from back wall, 18" from corner. There is no really "obvious" room feature that should cause this discrepancy. All 7 other speakers are detected at exactly the right distances.

Normally Audyssey should detect a sub like this as farther away than reality, to compensate for the time delay in the LPF filters.

Thanks.

[ganesha]

I would ask in this thread, you should get an answer there. The founder and CTO of Audyssey posts replies there as well.

http://www.avsforum.com/avs-vb/showthread.php?t=795421

[cfraser]

  I have asked there. He didn't have an idea...he gets asked a lot of stuff and probably forgets my question since yesterday, or doesn't have another suggestion. I thought asking here would be good too, since probably more people reading here would have ACI Titan subs than in the AVS thread, and might have tried Audyssey with one. I guess what I'm trying to find out is: it it something "unique" about the sub (can't imagine what), or is it something about the room (some strange resonance or construction or ??...Audyssey is supposed to get around most things like that, it's purpose).

I have to say, it does sound quite good with the setup Audyssey did, regardless of the "wrong" sub distance. BTW, I have been running the HT system with Audyssey for ~8 months, was just re-doing it because of some new gear, and thought I might get an answer for this "short sub" thing now with more user experience out there.

[Mike Dzurko]

It's because our subs are so fast  . . .

Seriously, I don't know why you'd get those results. I'd be curious what effect changing the phase on the subwoofer has on this as well as what effect changing the crossover frequencies on the sub has.

[ganesha]

I was looking at the Integra DHC 9.9 manual today and noticed this under the Audyssey setup section:

"Because of the complexities of low-frequency sounds
and the way they interact with a room, THX recommends
setting the subwoofer level and distance manually."

I guess because of weird issues like you're having   

[cfraser]

With Audyssey you cannot change the sub distance manually, as that will screw up the calculated settings. It works in the time domain. Time = distance, and vice reversa.

If you change Titan LPF settings (away from the max. frequency setting), Audyssey will find the sub farther away due to the sub filter's time delay (it doesn't take much to make feet of distance at the speed of sound). Thus, for LPFs that can't be turned off, Audyssey *should* always find a sub *farther* away than it really is...and thus my query. The LPF time delay depends on their settings, so it's frequency dependant, and we don't want that for something working in the time domain. Ideally for Audyssey you want to turn the LPFs off. Anyway, for Audyssey you set the Titan up as recommended in the Titan manual for "Theater" input use, except with phase at 0.

I have not tried adjusting the Titan phase with Audyssey, as it is also frequency dependant.

[cruz123]

I just think the bass tone of a sub is difficult for the mic to pick up.   If you hold up an SPL meter while the test tone is playing for the sub you will likely find that the SPL meter also struggles to measure the volume at a consistent number.     I always run Audyssey for the equalization settings, but then set the volume of each speaker manually with an SPL meter (using the test tone in my receiver) so that the volume for each speaker is the same at my listening position.

[cfraser]

Not with these mikes! Quite amazing IMO, for the price. They are calibrated within 2dB, and the calibration curve is stored within the electronic device with Audyssey built in...must use the exact mike for the device for this reason. As Audyssey says, they are NOT just "cheap little mikes". They use these kinda unique warble tones too.

There is no problem with Audyssey setting up the Titan *level* just fine IMO, it's the matter of coherence and overall sonic integration that depends on correct distance interpretation to the sub. Regardless for my case, it still sounds fine to me, but just knowing something isn't kosher irritates enough...

Edit: don't mean each mike is individually calibrated, just that the mike model has a curve associated with it, and *that* varies with each Audyssey device, and the more you pay LOL.

[Mike Dzurko]

If you're now using the Theater input I'd recommend switching to one of the other inputs. The Theater input rolls off higher than the other two inputs.

http://www.audioc.com/SVold/titan/titaninputs.htm

I'd also recommend adjusting the Titans internal filters down to a little above, but close to where you're crossing over. You'll have to re-run the Audyssey setup, but the results will be worth it.

[cfraser]

Let me think about this some more. I didn't know the Theater input was "unrecommended".

Firstly, I use the L/R inputs with my 2-channel setup: I pull the Theater plug, push in the L/R plugs and twiddle the knobs.

I have run Audyssey using L/R inputs and with LPFs set for 40Hz (my music system XO) and with level/phase set appropriately, and used it this way for quite a while. For whatever reason, this didn't sound very good with Audyssey.  Bass was too boomy this way. Maybe it's my pre-pro (actually a Denon 3808 AVR, amps not used). I think the way the Audyssey is set up in this 3808 it only wants to use the LFE for bass management. However: Audyssey did in fact detect the sub at the *correct* distance this way.

Just thinking out loud here: maybe the better results would be obtained by telling Audyssey I have no sub (and afterwards adjust the sub setup manually, like for my 2-ch system, via the L/R inputs). I don't know what Audyssey would do with the LFE then...I'm pretty sure you can "add in" the sub to the config later though, the same way you can manually adjust channel levels and individual speaker XOs, and the LFE would just not be "corrected".

Anyway, lots of options.

Edit: I read more of the Titan XL hookup info on your site, and I think I misunderstood part of what you were saying. There is much additional hookup option info there not in my (old) Titan manual. You are suggesting I use *one* of the L/R sub inputs connected to my AVR LFE out (not using both the L/R AVR pre outputs to the sub...what I thought you meant). That sounds like a really good idea...and I will do it.

Is my Titan II LE electronics set up the same as the XL electronics, re the inputs and their rolloff etc.? It looks roughly the same from the amp diagram and description... Thanks.

Audyssey highly doesn't recommend using any of the sub controls (except level), or any other sub equalisation. And it's not just a "proprietary interest" sort of thing: people at AVS generally report poor results (and additional complications), better to just let Audyssey do the whole thing (or not at all, as preferred). Now I am talking MultEQ XT, which is much more sophisticated with the low sub frequencies than some of their lesser versions.

[Mike Dzurko]

Yes, your LE electronics function just like the current XL series. I'll be interested in how you get the best results.

[cfraser]

Something is wrong in the firmware I think. It has been updated by Denon since I last used Audyssey, and it worked OK before.

If I move the mike 1' farther away, the sub distance gets measured as 1' closer. If I lower the LPF frequency, the sub "moves" closer and closer...exactly the opposite of what should (and used to) happen. In fact, I can place the mike and adjust the LPFs so the sub is calculated 0' away from the mike, when in fact it's ~15' away (didn't try for a negative distance, if possible LOL). I'm thinking somebody got a sign wrong in the calculation.

And it does sound OK, nothing grossly sonically wrong like it is possible to get (on purpose, just to see...). Now, it is quite possible that correct distances are being measured, and used in all the calculations etc. Audyssey does. But they could just be displayed incorrectly i.e. the translation algorithm is incorrect. Regardless, it's not the sub that's the problem.

Edit: Denon is "on the job" and will test the same HW/FW as mine to see what's up. Hadn't heard of ACI (not too common in Canada), and apparently checked it out and was impressed by the subs he saw.

[cfraser]

After many further experiments...

Is there anything "unusual" about the phase control in this sub? IOW, does it work in the same way as phase controls in most other sub amps? I have never owned any other subs.

Thanks.