PDA

View Full Version : What is the best sub set up cd.



King
03-17-2009, 08:10 PM
Current best sup set up cd or Blu ray?

At 0 setting on the volume, the sub db should be what, for reference level?

Thanks

curtis
03-17-2009, 08:33 PM
At 0 setting on the volume, the sub db should be what, for reference level?

The same as any other speaker. If you set each of your speakers to 75dB, then the sub should be set to 75dB.

King
03-18-2009, 01:27 PM
The same as any other speaker. If you set each of your speakers to 75dB, then the sub should be set to 75dB.

It does not seem right, using the pink noise from my AVR and SP meter.
The sub seems light using this technique. I realize I can turn it up.
I thought there was a special CD,SACD or Blu Ray for sound set up??

Thanks

curtis
03-18-2009, 01:46 PM
It does not seem right, using the pink noise from my AVR and SP meter.
The sub seems light using this technique. i realize I can turn it up.
I thought there was a special CD,SACD or Blu Ray for sound set up??

That is what people usually say for the first time. Have you tried listening to music or movies with it set that way?

the Avia disc is good for calibrating.

TooManyHobbies
04-03-2009, 04:33 PM
Like King, I also set up my new dual F15 subs using the pink noise from my pre/pro and an SPL meter. The initial impression listening to music was the bass was lacking. After some additional listening, the subs ended up being adjusted 2-3 dB higher than the mains as measured with the SPL meter. I'd also be interested in a setup CD, but am not aware of one. My brother-in-law is a bass guitar player and has a home studio where he records and mixes his own music. I've asked him to come audition my system with music he has recorded and mixed and give me his opinion of the sub to main level matching, but that will likely be awhile, since he lives 125 miles away. In the meantime, I've done some experimenting while listening to several hours of a variety of music and a couple movies, and I ended up returning to the setting where the subs are 2-3 dB higher than the mains using pre/pro pink noise. My wife and I are both happy with this adjustment.

I did notice that bass prominence (or lack thereof) varies from one recording to the next and particularly between older recordings (say, pre-digital masters) and newer ones even where the label and artist are the same. The newer recordings seem to always have more bass. I wouldn't necessarily attribute this to some feature of analog versus digital recording, but probably more due to changes in mixing styles over time. The 2-3 dB boost was a compromise over a variety of music in our collection. So, the media might have a significant influence on the bass levels one finds acceptable.

One final consideration is loudness compensation. Our previous receiver had loudness compensation, which we used, and the efficiency of our speakers meant we typically listened at fairly low amp volume levels. Our new pre/pro does not have loudness compensation, and although our mains used with the F15 subs have lower sensitive than before, we are still listening at relatively low levels, typically -30 to -32 dB on the volume control. I have not researched the loudness curve effect at these listening levels, but this could also influence the perception of bass between different setups.

Bill

Quinn
04-05-2009, 02:29 AM
Curtis, isn't there a correction table somewhere for the Radio Shack sound meter being off a few dBs at lower Hz?

EDIT- Found it at SVS....


So find out what your subwoofer(s) are REALLY doing, and add the following numbers as appropriate to your SPL meter readings:

At 10Hz add 20dBs to the meter's readings and at ...

12Hz add 16.5dB
16Hz add 11.5dB
20Hz add 7.5dB
25Hz add 5dB
31.5Hz add 3dB
40Hz add 2.5dB
50Hz add 1.5dB
63Hz add 1.5dB
80Hz add 1.5dB
100Hz add 2dB
125Hz add .5dB

Mike^S
04-05-2009, 11:44 AM
Edit: argh wait a minute, I think I was right the first time. If the meter says 75dB, then the sub is probably putting out around 77-78dB. So that means if you set your mains to 75dB, then the sub should be set to 72-73dB.

King
04-05-2009, 07:22 PM
Yup, that means your measurement for the sub should actually be 2-3 dB less than your mains when measured with the rat shack spl mic.

Now I am confused...
Does this mean set the sub 3 db less then the mains using the pink noise and the shack meter?

Mike^S
04-05-2009, 09:53 PM
Now I am confused...
Does this mean set the sub 3 db less then the mains using the pink noise and the shack meter?

Edit, I think I was right the first time. lol

Quinn
04-06-2009, 10:53 AM
Now I am confused...
Does this mean set the sub 3 db less then the mains using the pink noise and the shack meter?

Yes.

From SVS-

Simply look to the below frequencies and add the required decibels (dBs) at the frequency in question. So if your system seems to be measuring 70dBs with a 20Hz tone, then really it's putting out 77.5dBs

TooManyHobbies
04-10-2009, 07:16 PM
The Radio Shack SPL meter has two settings for filtering, "A" and "C" (often referred to as "weighting"). Some research defined "A" as being frequency compensated to hearing sensitivity (I assume Fletcher-Munson) and "C" as being flat frequency response. I could believe those add numbers using the SPL meter on "A", but I used "C" and would not expect this low frequency boost. If I adjusted my sub levels using the add numbers provided, I think that would result in setting the sub levels lower, although I have no idea what frequency the pre/pro test tone is. The sub level already seemed a little low on some recordings, not too high. Unfortunately, I'd need some adapter cables to hook my frequency generator up to the audio gear, but maybe I should try that sometime and see what the results look like with some known frequencies.

RythmikAudio
04-10-2009, 08:26 PM
The Radio Shack SPL meter has two settings for filtering, "A" and "C" (often referred to as "weighting"). Some research defined "A" as being frequency compensated to hearing sensitivity (I assume Fletcher-Munson) and "C" as being flat frequency response. I could believe those add numbers using the SPL meter on "A", but I used "C" and would not expect this low frequency boost. If I adjusted my sub levels using the add numbers provided, I think that would result in setting the sub levels lower, although I have no idea what frequency the pre/pro test tone is. The sub level already seemed a little low on some recordings, not too high. Unfortunately, I'd need some adapter cables to hook my frequency generator up to the audio gear, but maybe I should try that sometime and see what the results look like with some known frequencies.

I have a full testing equipment to measure the frequency response of subs in room and in close-mic position. Even with that, I have found an SPL meter to be very valuable. I have compared the results of A-weighting with the results measured from lab grade microphone and they are reasonably close. Even though Radio shack analog SPL meter seems to be very popular, I do favor those made by Vellemen or other brands with digital readout and round windscreen sock (which helps prevent cone hitting mic during close-mic measurements). They can be found on Ebay and Amazon.

In addition to SPL meter, one also need a CD with various warbled tone frequencies. I have Stereophile test CD2. It starts with 1khz, and then jump to 200hz. A warble tone is a sine signal that warbles in frequency. By warbling the tone, we get an average over a finite bandwidth. If we use a single tone sine wave, the reading will be very unreliable as a slight hand movement can give you a different reading in a room. I use tripod too, out of convenience, not necessity.

Now the measurement method. There are basically two types of measurement methods, one is call near field (or close mic) and another is in-room. The in-room response will very much be affected by room modes below 200hz. Above 200hz, the reading from in-room response becomes very reliable as the frequencies of room modes are so dense between one and the next so that they certainly will fall into the bandwidth of a warbled tone and achieve the goal of returning an average value. On the other hand, the frequencies of room mode is farther away from one to another below 200hz, one can easily pick up all sorts of peaks and dips. In other words, the bandwidth of warbled tone cannot cover multiple room modes at the same time. To verify the "correctness" of subwoofer frequency response, I would recommend to do a close-mic first. For our subwoofers in particular, one should get flat frequency response with -3db at 14hz assuming the SPL meter is reasonably accurate. Then whatever the peaks and valleys one gets from the in-room measurement is due to phase alignment and room modes. These problems should be addressed differently.

The procedure of measurement is to start with a midrange reading as a reference. 1khz is a good one because our hearing is very sensitive to that frequency. Next I will jump to 200hz and go in smaller steps below that. BTW, prepare a spreadsheet and write down all readings and perform analysis later.

TooManyHobbies
04-10-2009, 10:28 PM
Radio Shack also has a digital SPL meter for only a few dollars more than the analog model. I have had the digital model for at least 10 years. The Velleman digital meters have greater resolution, and I'm sure accuracy as well, but at least at the one source I looked at, they were more than three times the price. For my occasional use to set up the home theater, I've been happy with the Radio Shack meter, and for my non-professional use, I have a hard time justifying the extra cost. Doing the setup with a SPL meter has sure beat doing it without one.

I am in the middle of a system upgrade that is replacing large, floor-standing main speakers with a bookshelf and sub setup. Previously, a sub was only used for movies with the full-range main speakers used by themselves for music. It took me awhile to decide on subs for the new setup because of their use in reproducing music, and the final decision was dual F15's. My wife and I have been listening to this new setup for about a month, and we are very happy with my subwoofer selection. My wife's only regret is that the Rythmik subs are not available in wood veneer, but I'm sure that would be out of our budget.

Regards,
Bill