Speaker Level Calibration -- Tone Generation

TonyPTX · December 2002

Hey Folks.....I've been silently ratting the forums for about 3 weeks now looking for the holy grail of cheese. I "FINALLY" picked up a new set of Polk speakers to upgrade my aging (circa 1980 yet still kicking) JBL floor standing speakers (god I must have repaired the cabinets on those guys a dozen times). ANYWAY, back to the point, I replaced the JBL's with the RM6700 Sat Combo and a PSW404 Sub (very nice combo indeed). I picked up a Rat Shack Digital SPL (I was never good with analog meters ...too lazy I guess) and have used the built in tone generator in my Onkyo SR600 to calibrate all the speakers to 75dB based off of the left front channel at 0dB adjustment. Odd thing now is this weekend I picked up the Sound & Vision HT DVD Tune-Up kit and I was going though the audio tune-up setup to verify everything and lo and behold...the speaker balance calibration from the DVD showed very different readings (+/- 5 dB) in the levels of all the speakers. IE...Onkyo internal pink noise generator, all channels are at the same dB level. S&V HT DVD sound balance, the channels vary +/- a few dB's and in extreme cases +5dB.

So the question is, "What's a guy supposed to do here?" Do I balance off of the Onkyo internal generator or the calibration DVD? My fear here is that using the DVD may make the movies sound good, but when I listen to music or CD's the levels will be off (dedicated CD player different from the DVD player).

Any takers here?

System specs below in the sig. DVD player is hooked up via TOS link cable. Sub is connected via Polk's "recommended" speaker level line in, front as "large" and sub as "off." (I still haven't bought into this cow yet but I'll see how it works out.)

PS...this Forum really rocks. It's nice to see people actually helping each other out for a change. I know I've answered some of my dumb questions by just reading around in here.

Tony

grinchman007 · December 2002

Tony,

I could never figure out how to use the SPL meter correctly myself. I purchased the RM7600 a few weeks ago. Went down to the ole Shack and picked up a digital meter as well. I thought I had everything set, popped in a DVD, now find myself adjusting the center, surrounds, etc...I am curious to see if someone offers some sugeestions.

I do have a question for you. When connecting your sat/sub system, what method did you use (the recommended Polk connection (mains from receiver to sub, using sub's crossover) or
mains directly to speakers, set to small, and use the LFE to sub)?

I have searched and searched, but have not found much (I know my ears should be the judge) but I am looking for someone with a convincing arguement either way.

Thanks

TonyPTX · December 2002

...using the SPL meter is not a problem for me. It's just what should I be using for the reference signal/level that's confusing me.

I'm using Polk's "Recommended Method" which is the line level to sub and then sat's off of the sub with Front set to "Large" and Sub to "off". Like I said in the post, I haven't bought into this yet (thinking that Polk suggests this method to make it easier on them to troubleshoot poor sound quality for people who have cheap recievers).

grinchman007 · December 2002

Tony,

I apologize, in my haste to reply, I totally skipped over your statement. Serves my right, for trying to work and play at the same time. Thanks for the quick response.

danger boy · December 2002

Originally posted by TonyPTX

So the question is, "What's a guy supposed to do here?" Do I balance off of the Onkyo internal generator or the calibration DVD? My fear here is that using the DVD may make the movies sound good, but when I listen to music or CD's the levels will be off (dedicated CD player different from the DVD player).
Tony

TonyPTX,

you should calibrate your speakers by using the calibration DVD instead of your Onkyo internal pink noise generator. Reason being.. that will give you a accurate level coming from your DVD player and into your receiver via Toslink. This will be more accurate. the levels from your CD player won't matter much. because audio CD's for one do not have much low freq.. so your sub will sound very low compared to a DVD. and while listening to CD's i assume here.. you will not be listening to it using all 6 speakers. correct? good luck

TonyPTX · December 2002

grinchman007: Shhhh.....same here don't tell the boss....:eek:

danger boy: I'm finding myself using the All Chn Stereo option more with the new speakers (withdrawl from having a full range and fullness that my old JBL's were able to produce). I'll take your opinion to the bank and collect the concensus of some other folks and make my decision then. Thanks for the quick response.

wlrandall · December 2002

I wasn't happy with my calibration until I bought the AVIA DVD and used it. Internal generators aren't worth a darn to me.

I also used a pretty high reference point of 85 dB. SLM was set to A weighting, fast response and placed at ear level in the center of the sofa. Remember to cal for the different modes as well (stereo, DTS, DD5.1, etc...).

Wally

HBombToo · December 2002

For accuracy sake I would always default to the test disc.

Furthermore, the media that you will expect the most from will be your dvd player. Ensuring the audio is set right with the dvd player then adjusting all your other inputs to match will enhance your TV, CD, VCR or Satellite listening experience. If you notice a loss in volume going from 1 medium to another, "I'll bet a six pack you will", simple up/down on your volume will be the fix.

HBomb

Dr. Spec · December 2002

I agree with all here - use the calibation DVD. The new VE Digital disc will be available very soon for around $20. I'll be picking it up as soon as I can find it on-line - it will be a very good value with calibration stuff for both audio and video.

The only thing I would add is definitely use C-Weighted Slow for the SPL meter setting. C-Weighted allows for a more accurate reading down into the low bass frequencies, whereas A-Weighted is only accurate above 500 Hz or so. Also, the Rat Shack meter reads about 2 dB low on the bass test tone.

Fast gives a very "jumpy" reading on the meter, especially on the bass test tone. Fast, however, is very useful for determining SPL peaks on HT playback. Slow allows the meter to stabilize and give a more average reading for SPL on test tones - especially important on the digital unit. That, BTW, is the main reason most people buy the analog unit - it's easier to estimate an average reading on the display.

Doc

TonyPTX · December 2002

Thanks Everyone.

I think I've gotten enough responses here to convince me to use the calibration DVD. Now if I can only get someone to sell me why using the speaker level inputs to the sub is better than running the sub pre-out...

Dr. Spec · December 2002

If you have a variable x-over in your receiver, then there really isn't any difference. Can you set your x-over on small to 100 or 120 Hz?

Reason being, with small satellites, they only have decent mid bass down to about 100-120 Hz, and trail off badly below that point.

Many HT receivers use an 80 Hz x-over to the sub on "small", and are not variable. If this is the case, and you have sats, then LFE method will leave a mid bass "hole" in the FR between roughly 100 and about 70 Hz.

With larger surround (mains, center, rears, etc.) speaks that are flat to around 50 Hz, the LFE pre-out method is no problemo and easier to set-up.

Doc

TonyPTX · December 2002

Doc....as always an inspiring comment and I really enjoy reading your comments. If I didn't know any better, I'd say you've been doing this for a while.

The Onkyo receiver I have is capable of 80-100-120 Hz X-Over settings for the small speaker setting. Running the S&V DVD this weekend (there is a really nice audio test to check sub Low Pass x-over setting) I noticed a thinning in the audio tone as it cycled down in frequency (but still audible) as the signal transitioned from the sats over to the sub. Then again, I still need to take everyone's advice and re-calibrate all the speakers to the same dB based off of the DVD level calibration and not the Onkyo Pink noise generator. We'll see if that thinning lessens.

As always, thanks for the quick responses. I don't think I've gotten any real "work" done today at the office...:rolleyes:

Rotarydude · December 2002

Never use tthe internal test tones. Why? Because tthe engineers that programmed the test tone is giving a general idea where 75db would be in an average room. If your room is very large those test tone might never hit 75db. If your room is small it will be always be over 75db.

Use a test disc, as this will give you the control to find 75db dead on with a test meter.

wlrandall · December 2002

Doc,

Thanks for pointing that out regarding which weighting ot use-didn't consider that and I'm just accustomed to using A from work.

In regards to jumpiness when using "fast", I didn't have that problem with the B&K digital meter I used. Maybe it's dependent on the manufacturer.

Wally

Dr. Spec · December 2002

Oh well why didn't you mention B&K?! Damn they make nice meters! I use one too - model 2205 - and they don't require any correction for bass like the RS model does. Good deal my friend - B&K is professional grade stuff. I still recommend slow for test tones, though, regardless of meter manufacturer.

Doc

Dr. Spec · December 2002

Tony: Try 120 Hz and see if you still have a thinning type response. I'm betting you won't. You might run into sub localization at that frequency, though. Give it a try at 120, and 100 and see how you like it. I wouldn't go lower than 100 with small sats, though.

Doc

grinchman007 · December 2002

A question for Dr. Spec,

I have an older model Yamaha (RX-V905) and the crossover is set (according to the manual) at 90. I am not able to manipulate the settings and I see you recommended to try 100 above. Do you think there will be much signal loss at 90?

Tony, thanks for starting a great thread.

Thanks to all, Mark

Dr. Spec · January 2003

Originally posted by grinchman007
I have an older model Yamaha (RX-V905) and the crossover is set (according to the manual) at 90. I am not able to manipulate the settings and I see you recommended to try 100 above. Do you think there will be much signal loss at 90?

What is the recommended x-over range for speaker level connection at the sub for the RM7600? There should be a "whited-out" range on the control back there or the manual should show some preferred range of frequencies. If 90 falls within that range, then you should be OK. That goes for everyone in this thread. I think 80 is too low for sats, that's all. I use 80, but I have full range speaks all around.

Doc

Speaker Level Calibration -- Tone Generation

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