Some Sub-versive Thoughts..

[Susan]

I've just spent a VERY frustrating evening using "Sound and Vision"'s new version of the Avia disk. Don't get me wrong...while the commentary borders on cutesy, it's a far better production and written in easy-speak so that common man can finally understand what it's all about without having to join a forum and read the archives for a week. :=)

They actually explain some goodies like the diff between composite, S-video, and component outputs, etc. They have a section explaining about the sound meter and how it works. It contains a section for 6.1. And for those who don't want cutesy and want just the tests, you can menu ahead. All-in-all it is a good re-do, and I think Avia was smart to go with marketing it thru S&V as they havn't done a smash-up job of getting the product out..even BB doesn't have it.

My frustration lies with the sub..it seems we pay mucho payola to get these big hunks and then we calibrate them down so as to not hear them. Am I missing something here? Obviously I like to set them lower for music as I don't like an excessive amount of bass in my "normal" music (not counting beer-busts with Bob Seeger or my operatic performances with Queen in the privacy of my home...). But on movies with lots of special effects I want good, strong, clean, butt-galloping bass..and my two new SVS 20-39CS's do the trick. But after calibration I'm down to clean, "nice" bass. But, like Tina said, "sometimes I like it...", but, I'm digressing again..

Do you jack yours up much for movies? BE HONEST. You're slipping the Pod Race into your DVD and you pick up your remote to tweak it up a bit and.......HOW HIGH DO YOU GO??

Is this just becasue I've finally got clean, distortion-free bass and I'm overdosing? Will there come a time when my lust for a vibrating derriere will recede? Will we all develop permanent nosebleeds?? (My hub swears his blood pressure goes up since we got the SVS's..) Was it only the champagne and tomorrow I won't be this entralled??
Over and Out

[Clive]

Susan,
I for one, depending on the movie we'er watching do go for that volume increase and a xover adjustment on my sub. Most times the Avia calibration works for things I watch or listen to. But my center and my sub does get an extra tweak sometimes! I hope this is okay.

At times I'd make my increases or decreases based on the "Dial norm" info. of each disc.




CLIVE




HEY!! Why buy movie tickets when you can own a Theater?

[Andrew Pratt]

Susan there could be a couple of things going on here that are affecting the reading you are getting. Remember that when properly ballenced the sub should have a lot of output when set to the same SPL the other speakers so my guess is something is a miss in your readings. Now becasue the other speakers are generally being calibrated with much higher freq's there aren't the room nodes to deal with so they tend to me more accurate and even across the room. The sub on the other hand with its long wave lenghts can be a tricky thing to get set right. What I'd suggest you do is set Avia to AB loop the sub calibration test tones then with your SPL meter walk around the room and see how much variation there is in the readings. My guess is that the spot you were taking the reading from is in a null and there fore is giving you a much lower reading then should be. If thats the case you might have to move the seats a little forward or backwards to get out of the null or move one or both of the subs until things settle out a bit.

[AndrewM]

The other thing to look out for is peaks in your subs response. If you have a big peak somewhere in the response, that is what your SPL meter will pick up when doing the level check, while the rest of your response is much lower (making it seem like you don't have much bass).

To visualize, imagine _____/\_____ is your response from 20-80Hz, on a regular pink noise test your SPL meter will read the loudest part, so you can imagine what would happen if you had say a 6db peak somewhere in your response.

I'd say add a nice test tone disc to your collection and sit down and write down your response and find out where you have peaks and dips.

Andrew

[Bruce]

I agree with both Andrews.

I also felt the bass volume was never correct between music and HT in my room before I used a Parametric EQ to cut my room's bass peaks. Now, I never adjust it anymore.

You need to do a frequency chart for bass frequencies in your room (20Hz-200Hz) to get an idea of what's really happening.




Bruce
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[ThomasW]

Nothing is cast in stone regarding audio and audio calibration for HT. It's your system so set it to sound like you want. The idea that there is a mandatory 'ideal' calibrated reference setting is silly, because each HT is unique. And it's doing not playback for a real theater where SPL choices are made with a completely different criteria.

I understand the marketing psychology for these discs and the need people have for a 'reference standard'. But more realistically I really think that these discs were developed for people that can't or don't want to think. Just blindly follow the directions and everything will be calibrated? No way...

I've had a large format (FPTV) HT since 1989 and never found 2 movies that had the same output levels. So as far as I'm concerned setting calibrated levels is a joke. Every movie needs to be tweaked (technical term is 'gain riding') during playback.

Try using one of the little freeware tone generators and the RS meter. The goal is to match the output levels of the sub and the mains. This also a cheap and easy to see how flat the system is overall. If you have something like a Behringer DSP1100P/1124P, it's quite easy to make an Excel spreadsheet and then convert it into a frequency plot for adjusting the EQ

I run my subs EQ'ed 'flat' for music. Then simply raise up the overall sub output level +3db or more for HT. It's fairly easy to know when the level is raised too high, because the elevated bass will have a negative inpact on the tonal balance of the midrange. If/when that occurs that's when it's time to drop the sub level a couple of db.




theAudioWorx
Klone-Audio

[Sonnie Parker]

I've got my website semi going and plan on uploading some test tone cd's in mp3 format within the next week or so. I may upload each tone and groups of tones such as 1/6 octave, etc. I have recorded a large group of tones at 10 seconds each fading in and out the first 10% and last 10%. They have come in really handy for me.

I do have my sub set a little higher than my mains. But, I am just about totally movies. Plus I'm a bass freak ta boot.






SONNIE

Cedar Creek Cinema

DVD Collection

BFD Comprehensive Setup Guide

[JonMarsh]

Well, if I really had an HT, I'd probably have some quirky opinion or another but in general I would second Bruce and ThomasW.

Spending some time with the positioning of your speakers, sub, and listening position, and if necessary taming the peaks with an EQ will do a lot to alleviate subjective imbalance between different program sources- both music and HT. If you've got a null due to positioning in your room that happens to be the note your favorite pop musician likes a lot (it's his "key"), then just adjusting a simple sub level control will just make things confusing the next time some different program comes along.

And Thomas is quite right about DVD audio mastering quirks- heck, we've even seen that in CD, such as two versions of the same Pink Floyd album with nearly a 10 dB difference in recorded level. Boys and girls, can you spell "sloppy mastering"? It hasn't gone away with DVD- just read about the gaffs and recalls that occur. And those are just the ones they can't ignore or gloss over.

And then, let's face it, we've just become acustomed to somewhat rubenesque bass response in the typical cineplex and sound track. I think once you get things really smooth in response in the home cinema, deep and clean and smooth all at the same time, you may eventually scale back on the overall bass level to closer to music. But, I also suspect that at times it's not the bass that's too loud, it's the mains and the distortion than may have you reaching for a gain ride, while you'd still like the thrills in the bottom end. A lot depends on how dynamic and clean the whole system is.

In the end, it's how you enjoy it that counts.

-Jon




Earth First!
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We'll screw up the other planets later....