Axiom Home Page Forums General Discussion Technical Questions What to do with EP600 for Audyssey calibration?

When I'm letting the Audyssey MultEQ XT do its calibration for my 7.1 setup (Epic 80-600 with QS8s and M80 center), what should I do with the settings of the EP600?

Do I give it full range and let the Audyssey figure it out and roll it off, or should I put the crossover at 60-80?

No copping out and saying "try it both ways and use whichever sounds best to you".

Thanks!

- Nuke

I would let the Audyssey do it's thing and modify from there.

Try both ways and use whichever sounds best for you.

Seriously, that's really the best answer. If it wasn't an EP600 (or 500 or 400), I'd say put it at bypass, but there's been some indication that it sounds better with the crossover set.

The denon 3808 manual says to put the sub's crossover to bypass during the set up.

for my 500 I had the crossover set to bypass with the volume at about 50% during the audessey set up.

That's how I did mine as well with regards to crossover. Trim to "flat". It doesn't really matter where you set the volume, in my experience, Audyssey tames it to -12 no matter what.

After the Audyssey does it's thing, adjust the sub volume to taste. Don't worry about damaging the driver by overdriving it, the DSP prevents that, a pretty reassuring feature!

Nuke, if you're using the crossover in the receiver, either set manually or by Odyssey, there's still no good reason in my view to also insert the internal sub variable low pass filter. Set it on bypass.

Ignore what Audessey suggests for subwoofer settings. It like all auto-equalizers are inaccurate for frequencies below 100hz. Audessey is one of the worst in this regard. Better to set up delay, level, crossovers manually.

John, what you're saying is really unfortunate. The only reason I would even consider buying an Audyssey-equipped Denon is to manage frequencies below 300Hz. If Audyssey can't do this, in my mind it's worthless.

Mojo,

No EQ program is perfect. Audysey will do just fine for gettting you started and most comsumers will be quite happy, considering they don't even know what an SPL meter is. I rather like what it did with my set up and after further set up with a meter and Avia / DVE test disks, I found that I changed very little.

I can see how Audessey may help smooth FR in the upper frequencies but there is no way it can calculate optimal settings down low. The physics involved make it very difficult for an automated program with limited processing power to do well. Fixing FR problems with automatic electronic correction is a tricky proposition requiring huge amounts of dedicated processing power to calcualte iterations.

I have rarely seen any automated program which actually set equalization/delay/crossovers correctly for subwoofers. Its actually refreshing to buy equalizers (DEQ2496) with auto-programs where the manufactuer(Behringer) specifically warns not to use such programs for frequencies less than 100hz.

The fact that the Audessey programs in receivers are marketed as one stop silver bullets is disingeneous to me. To do the job properly across all frequencies requires far more processing power than you find in the typical receiver. Indeed even to address correction strictly in the lower frequencies is a formidable task. The Velodyne SMS-1 for example does a reasonable job up to 200hz but limits resolution to 1/3 octave because of processing limitations. Meridian and Lexicon limit their scope to only addressing long decay times rather than flat FR below 250Hz. Interestingly both of these companies recommend using room treatments to address flat FR rather than use equalization because of the limitations in the devices.

One always gets better results by doing such equalization and delay settings manually.

How many years away is the processing power required, do you think? What kind of processing is it? Would a general-purpose type processor work, or would it have to be specialized?

The kind of processing power required is the type in your PC or notebook, which you are not going to find in a receiver or dedicated equalizer anytime soon. Audessey has a PRO version that connects to a PC. It takes longer to run and requires some technical savvy but it is more accurate. In the meantime it has the inaccurate version which it liscences to to receiver manufacturers. Those versions are somewhat effective for HF correction but their effectiveness drops pretty quickly at the lower frequencies.

The most effective bass equalizer which does power off a notebook or PC is the Room Equalization Wizard which is also free software. It finds optimal settings for the Behringer equalizers.

One product I have been watching with some scepticism is a new product development by Audessey which attempts to correct time and frequency domain problems. Ringing can do just as much to hurt sound quality as uneven FR. Lingering notes at all frequencies caused by soundwaves continually resonating around the room can mask detail and articulation. In the bass region it contributes to boominess and less tight bass. The Audessey AS-EQ1 as its called is supposed to cure both FR and time problems but it is way behind schedule no doubt because of the even greater processing power requirement and the fact it can't be slickly packaged into a receiver.

While we are on the subject, what exactly does the Audyssey room eq in the 3808 do? (besides adjust speaker levels and distances)

Terzaghi. The Audessey website will give you much better info that I ever could.

http://www.audyssey.com/technology/multEQ_products.html

http://www.audyssey.com/technology/dynamicEQ.html

Just be mindful of the intro section:



From what I have heard and measured in various friends rooms those programs all mess up the low frequencies and its a coin toss whether they correct or wrong the upper frequencies. Nevertheless, they are worth experimenting with to see if those programs actually improve sound in your room. I'd suggest you would be better off with selective room treatments and concentrating on postioning your equipment. Equalization is only a last resort and one that only really works in the one sweet spot. Also keep in mind that using too much equalization to correct FR can and does contribute to ringing in the room.

I’m not convinced Audysey does much with the LFE channel other than set distance and DB. It set my distance at 23’. My sub is 10’ away, so I changed this to 16’. It set the DB approximately 3 DB over the mains, which is just where I prefer it.

If you go into the manual set up screen on the 3808, you can copy the curve that Audysey created. After you copy it, you can tweak the EQ levels for each channel. There are 9 frequency ranges that you can adjust (63H, 125H, 250H, 500H, 1kH, 2kH, 4kH, 8kH and 16kH). Considering that there are only these 9 ranges that can be adjusted, I’m guessing that’s all that Adysey adjusts, and only one of them is in the LFE range.

Mdrew, Audessey set my sub at 20.8 ft when the distance is actually closer to 10 or 11.

I thought when I mentioned this in the 3808 thread your reccomendation was to leave it as is.

Do you think I should change the distance of the sub?

If you have an EP600 sub 10.5 ft away, I would set it at 13.5 ft. The delay of 3ft accounts for the longer DSP time difference in the sub. You should be able to blend with your speakers better with that delay.

I have an EP 500, but I assume the DSP time difference would be the same?

My 600 is 11 feet away and I have it set to 19 feet. Now whether it should be 19 or 15 is anyone's guess but I can tell you that if I go above 21 or below 15, the 600 sounds too "loose".

Is there any way to determine the best distance to set the sub or is it just by ear?

The timing is frequency-dependent. You can do a time domain analysis and use the second moment about the mean. Personally, I skipped all that and did it by ear giving me ample time to consume my beer .

Terz,

I have always added six feet to my sub's actual distance, but I'll give three feet a try as Jake suggests (he's the sub guru). I originally recomended that you leave it as is because if you go making several changes at once, you'll end up chasing your tale. Make small changes, and only one at a time.

I've been playing around with the manual EQ set up and think I have it set up about as good as it can be, but I've been tweaking things slowly, and keeping track of what the sonic differences have been.

If this is all that's holding them back, I don't see why it hasn't made it into a receiver yet, especially at the higher end. And you'd think they'd make dedicated hardware specifically for that task. I admit I know nothing, but to me, it seems like it has to be that the software isn't mature enough, not the hardware. Otherwise, I don't see how we couldn't see very advanced room correction within 5 years. Assuming the software needs the fastest processor there is currently, there's no way it couldn't be cheap enough to implement in that timeframe.

Correcting room acoustical issues electronically is a very complex undertaking requiring sophisticated software and dedicated fast hardware . Doing proper measurements alone takes a massive amount of processing time because it involves running iterations of sweeps and adjustments. More calculations are required for the bass frequencies because of the nature of long wavelengths in the room.

The few programs that come close to doing it properly are the Audessey PRO which is very expensive and can be connected to a PC and takes a while to run; or Room EW which is free software used with a notebook. All the Audessey eq programs liscenced for receivers are ineffectual watered down versions with simplified algorythms designed to run just a few iterations, make computations then recommendations made on simplyfing assumptions. Those simplified rules rarely correspond with your unique room acoustical requirements.

That's why I always say that based on current technology in receivers, there is no way such a program can do as good a job as someone with a RS metre and a measurement tape. Perhaps one day they will as the technology gets better and the cost of processing falls but don't hold your breath anytime soon.

Sorry to bother. What is a bypass switch? My sub doesn't have the bypass switch. It only have two knobs, the gain control and crossover freq. control. Right now I have my sub gain knob set at 12 o'clock and sub crossover control know all the way up to 130Hz. Sub crossover control know all the way is the same as the bypass switch ON.

It is the crossover switch. It's highest setting is "bypass".

Thanks Eflardeau. Got it. This I will leave my crossover to the highest setting.