"Official" Audyssey thread (FAQ in post #1) - Page 190

Edit: 16 Aug 08: This project is ongoing. The most current version may be found at the top of page 191.

Thanks for that. I will add it.

Mark

Mine does this, as well. About the same numbers - ~13' actual, ~9' reported.

I've probably re-run >5 times, that has always been consistent. All the other speaker distances are accurate.

Since I'm a bad boy and have left my main's as large, I haven't really played with it, or tried to change the distance to the appropriate amount. I've basically assumed that there is something going on with the room geometry (and it's about as bad a room as you can have), and better to go with what audyssey "heard" rather than what is correct.

eric

Audyssey is correct. It is not measuring physical distance.

If you don't have double bass on, the peak is mostly coming from the sub's output, not the speakers. If you turn double bass on what you are going to do is boost the bass levels between 80 Hz and the speaker's in room -3 dB point and that boost will be corrected. Below that, where you lose correction for the speakers but not for the sub, the sound from the speakers will be uncorrected and consist of a variety of peaks and troughs at the listening position. The peaks at the listening position will reinforce the levels you're getting from the sub while the troughs may act to cancel what you're getting from the sub to some degree. Overall response is likely to become very uneven.

At 37 Hz, a 5 dB peak (the difference between 75 and 80 dB) isn't all that noticeable in some ways. The ear is used to uneven bass response indoors and is remarkably forgiving of the variation that occurs in rooms. One thing you can be certain of is that that 5 dB peak would probably be much worse uncorrected so it's going to much less noticeable than it was without Audyssey. The second thing is that adding more bass by turning double bass on is not going to reduce that peak. What it's going to do is to boost most frequencies below your 80 Hz crossover noticeably and if 37 Hz is below the -3 dB point for any speaker that frequency will be boosted even more by the room.

By all means try turning double bass on and you may even prefer the sound that way, but I can't see any way that it is going to be more even or accurate and lots of reasons why it could be much less even and more inaccurate.

Do you have a push-pull type subwoofer by any chance? I have seen this happen with these types of subs and we believe it is due to the way the phasing of the two drivers interacts. I don't have a full explanation for it yet.

Chris

Eric,

Thanks.

Something to add. When the sub was on the right hand corner of the room, the distance was near accurate.
When I moved it near the right front speaker (about 2.5 feet from roght hand wall), I see this difference.
So what you are saying may have some merit.

Thanks Chris

Is there anyway of knowing what that highest frequency is?

I initally EQed my sub with REW and the parametric filters in a BFD. I tried to tame the major peaks (not the troughs) this way, then let Audyssey loose on the whole system.
Probably the main reason I did this was because I already had the BFD, and because I thought the MultEQ filters would be able to EQ the sub better if they didn't have to cope with large peaks (which I had).

Keep in mind also that Audyssey will integrate your sub into the mains, as part of it's EQing.

My sub is a DIY. The 4 x 15" drivers are in a manifold built into the floor as a Infinite Baffle sub. The manifold ensures they act as a single source (under my centre). They are driven by a Behringer EP2500 pro amp. So I have no filters or restrictions apart from what MultEQ and my Onkyo 805 do. I have set the LFE's LPF in the Onkyo to it's highest setting of 120Hz.

Jeff
Are you saying your sub sounds much better without the Rane?

When you had the Rane in the loop, did you also have Audyssey EQing the whole system?

I've never tried running Audyssey in my current setup without my BFD in the loop, doing some initial taming of the sub.

That's what i do. I crouch or lie down on the floor next to/behind my seats.

BTW, don't let anyone catch you doing this.

Yes, much.


No, before running Audyssey for the first time, I defeated the parametric.


I wanted to see what Audyssey could do by itself.

Audyssey has the additional trick of looking at the system response over time and creating filters with that "in mind." Try it.

I think if you do some research on home theatre speakers you will find some quality bookshelf speakers with a matching sub, that will solve all of your Audyssey problems and suddenly you will find what a truly amazing sound system you have.

Ask a few questions in the speakers forums. With their advice, you should end up with speaker sizes that suit your room decore (although they may still be a bit small for the size of the room), and will be the best bang-for-buck you can get. By the sound of it, I think high efficiency speakers should be a priority, but most bookshelf speakers are not very efficient. They will still cost more than the speakers you have, but you will never regret it.

You mean I've got to run Audyssey AGAIN??????
My wife already thinks I'm a complete nutcase, locking myself in the room and entertaining myself with these weird sounding noises.

You did command her to be quiet, didn't you?

lol. I do the same thing. Luckily, I haven't had to explain to my wife yet...

"Command"???
I'm not ready to commit suicide just yet. Actually I do most of my testing while she is out of the house.

Love your website. Actually it's surprising how similar the designs and materials we've used are. However, my rear wall is a false wall about 16" out from the proper wall. The frame of the false wall is filled with various insulation materials.

I used 703 for the bass traps I have in the corners of my front (screen) wall - triangular like yours, but Mine are hollow. I built the pyramid shape for each corner, but the 703 only forms the 3 sides and the top and bottom of each trap. The 703 is not cheap in Australa, and hard to get, so I had to be content with the hollow bass traps.

I also have a large first-reflection panel suspended from the ceiling just like yours. I have two others on the walls as well.

Does boosting each speaker in the level calibration from what audyssey set it at have any bearing on audyssey's corrections? I would be keeping each speaker the same decimal amount apart from each other that audyssey set it at but just boost the levels higher.

Provided each speaker level is altered by exactly the same amount, nothing should be affected apart from the overall level of sound at a given volume level.

Why do you want to do this? You can get the same overall increase in sound pressure level at the listening position by simply raising the volume setting by the same number of dB that you're thinking of raising each speaker level. If several speakers are already set to levels above 0 dB by the setup, you may actually limit headroom by raising the levels even further.

Just wanted to do it so I didn't have to crank the receiver volume to like -10db. I guess it doesn't matter in the long run though. How about the sub level though, it seems like it looses alot of punch after audyssey calibration. If I crank it up some will that throw off the sound balancing that audyssey set?

Ok, I'll try to be a little clearer.

My 37Hz peak is severe. if I cross my fronts over at 80Hz and run a sweep with a 75dB target, the 37Hz should be something like 60dB with a 12dB/oct slope. But in my system the 37Hz peak is at around 80dB, EVEN when the speakers are crossed at 80Hz. So that means a 20dB peak, and I assure you, it's audible! The 60Hz peak is not AS severe, but still in the 12-15dB region. I see the reasoning for not correcting below crossover from a DSP power standpoint, but I'm just saying there can be severe problems that are not being adressed because of it. Had we had brickwall crossovers the approach would be fine, but the gentle slopes mean the problems can be severe even a full octave below crossover.

And like you said, 'double bass' was useless...

Well, receivers are expected to handle a volume level of 0 db. That's 'reference level' for an receiver using Audyssey so "cranking the volume to -10 dB" is hardly going to push the receiver.

As for the bottom end losing punch, a couple of things can be said:

- If you haven't listened to a system with the bass equalised before, it may well sound a little subdued compared to what you're used to but give it a few days before making up your mind and see what you think when you get used to the sound. We have a tendency to regard things which sound different as not as good as what sounds familiar to us and we need to take the time to become familiar with the new sound before making up our minds. After using the receiver for a few days, try switching Audyssey off to hear what things sound like without it and see what you think of the bass with Audyssey then..

- try turning the volume up to -10 dB of so and listen again. The ear is less sensitive to extreme high and low frequencies at low volume levels and its sensitivity increases as the volume level increases. That means that as you turn the volume up, the extreme low and high frequencies will seem to increase more than the midrange does so turning the volume up acts a little like a tone control in some ways. I said 0 dB was 'reference level' and DVD/BD soundtracks are actually engineered to be heard at that level in the listening position. You aren't going to hear the proper bass balance without turning the volume level up to that level, or somewhere close to it because of the ear's reduced sensitivity to those frequencies at low levels.

If you turn the sub level up you will do a couple of things which aren't good. You will change the balance of the bass content of all the channels on the disc which have content below a speaker crossover frequency being handled by the sub, and you will also change the balance of the disc's LFE channel relative to other channels. Depending on what sound is involved and what it's frequency is and where the crossover frequency is, that could result in some odd sounds. If you want more bass and you're listening at much lower levels than the 0 dB reference level, 2 better options would be to turn on 'night mode' or whatever the equivalent of that is on your receiver, or simply to use the bass tone control to turn the bass up a little. The best solution however, provided you can do it without running into problems with the neighbours or waking the kids or whatever, is simply to turn the volume up and get closer to the intended tonal balance of the soundtrack.

Turning all speaker levels up by the same amount isn't going to help because the balance between the sub and the speakers is going to stay the same and all you're likely to do is to play the disc at a slightly lower volume setting to keep the overall volume around the same. Provided the overall measured volume stays the same at the listening position, you really aren't working the receiver any less by raising the speaker levels equally than you would be if you leave the speaker levels where they are and just turn the volume up. The input signal from the disc is unchanged and the amp is producing the same overall volume level. The total level of gain through the receiver is the same and all you're doing is altering the gain in 2 different areas, the volume control and the speaker levels, by compensating amounts to produce the same overall result. Effectively you're "cranking the receiver up" by the same amount, to use your term, but hiding where you do it in the speaker level settings rather than doing it where you're going to see it in the overall volume setting.

Reasonable receivers, and I think any receiver with Audyssey correction qualifies as 'reasonable', are meant to be able to be played at the 0 dB level so setting the volume to -10 dB isn't going to push the receiver hard at all.

You've got something wrong. If you're using a frequency sweep test tone and a 75 dB target, the level you're measuring after setup and with Audyssey engaged should be 75 dB at ALL frequencies. It should not be down to 60 dB at 37 Hz. What Audyssey tries to do is to produce a result where the frequency sweep produces an even level across the whole frequency range. If the speaker is crossed over to the sub, most of what you're hearing at 37 Hz should be coming from the sub rather than the speaker but the overall level should be 75 dB if that's your target level.

Variations of +/- 5 dB at low frequencies is getting pretty smooth for a small room and a smooth response is what Audyssey is trying to achieve.

Ok, here's what I do...

I run Audyssey. It wants all my speakers as large, and in my my processor that means 40Hz -3dB point.

I know my system sounds better crossed at 80Hz and letting my subs do the low end, so I set all channels to small (80Hz).

So, I set REW up to take a fullrange measurement, with the fronts set as small. I switch off the subs so I get the fronts only.

I then tell REW this was a bass-limited speaker, and it should use a 75dB target crossed over at 80Hz. The target is therefore down to about 60dB at 37Hz. The actual measured level at 37Hz is around 80dB, even when the fronts are bass limited.

Thanks for taking the time to answer my questions and be so thorough about it David, appreciate it. Couple more real quick. What should I set the actual volume knob on my sub at before running audyssey, where I would normally have it set at 5 (audyssey then sets this at -15 in level calibration) OR should I set it around 2 or so to get audyssey to make it about 0 in level calibration and then afterwards I turn the knob back up to 5 or so? Also, switching my fronts from full band to an 80hz won't affect any setting? Wondering why my center is sometimes set to full band and other times is set to 70hz when it is capable of going below 40hz?

If Audyssey trims your volume level of 5 to -15, then I would definitely try again with your volume at 2 (or maybe even 1.5).

1- the basic recommendation is to set the sub's gain control around the midpoint of its range. If that is around 5, then turning it down to 2 is a good idea. Don't change the sub setting after running Audyssey. The sub's level is being controlled by the receiver.

2- Switching the fronts from full range to anb 80 Hz crossover won't change anything as far as Audyssey is concerned.

3- the reason for the difference in the centre speaker settings with different setup runs is probably due to minor differences in mic position. At low frequencies the wavelengths are quite long and small differences in position can have an effect. While a small change in 1 position probably won't do much, Audyssey is averaging data from a number of positions and small changes in a few positions may yield a bigger difference in result. If your receiver bases full range on a -3 dB point of 60 Hz, it won't take a big difference for this to change to a 70 Hz crossover setting. You will probably get the speaker set to full range if the -3 dB point measures as 59 Hz and if the measurement comes out at 61 Hz, above the 60 Hz decision point, there's a change to a 70 Hz crossover. It can only take a 2 or 3 Hz difference in the measured -3 dB point for the crossover setting to change if that difference occurs around a setting point. If you're setting the front L & R speakers to 80 Hz, I'd set the centre to that as well.

It's important to remember that what Audyssey measures is the in room response. Specifications are often based on anechoic measurements and what happens in a room can be very different to an anechoic measurement. In addition some speaker specifications can be optimistic. One thing that could be happening with your speaker is that there is a big dip in it's in-room response at around 60 Hz and Audyssey may be basing its -3 dB point on that dip. Dips can't be equalised easily because the more power you put into sound at that frequency the more power gets absorbed by the dip. The sub may not suffer from that dip because it's usually placed closer to a wall so the cancellation frequencies will be different. It's also built to take a lot of power at bass frequencies and can usually handle equalisation at bass frequencies better than many speakers.

Gotcha, I'll run audyssey again and see how it sounds after a few days as I do believe my hearing thus far has been skewed due to not actually having good speakers before (only HTIB until now), not having ever properly calibrated before, and having speaker levels turned way up and out of sync with one another. One last thing, I won't touch the level calibration done to the subwoofer by audyssey but you are saying not to touch the actual volume knob that is on the sub either? I figured if I wasn't happy with the bass output I could try turning the gain up and to see if it helped. I keep reading that listening at reference level will/can damage your hearing is this true? I have been listening to my reciever at volume -24db to -27db before audyssey corrections so after it lowers all my speakers levels like it does to -10db or so I would need to turn the volume to -14db to equal the volume I was listening at before?

Hi All,

While watching TV if someone is sitting on the couch I sit on the carpet (i.e. floor) in front of the couch. Now the question, if I take measurements at ear level in the sitting position on the couch and measurements while sitting on the floor will audyssey make appropriate corrections even though the ear level is different for the floor and couch.