Calibrating Your Audio With an SPL Meter

[saprano]

Big daddy i plan on getting a SPL meter from radioshack tomorrow and was wondering should i get the digital one or analog?
and what do you mean by you wont gain anything with rat shack model?

[Big Daddy]

Originally Posted by saprano

Big daddy i plan on getting a SPL meter from radioshack tomorrow and was wondering should i get the digital one or analog?

The digital model is easier to use as you can read the actual db. The analog may be more flexible. I bought the digital model about 10 years ago.

and what do you mean by you wont gain anything with rat shack model?

I am not sure what you are referring to.

[saprano]

Originally Posted by Big Daddy

The digital model is easier to use as you can read the actual db. The analog may be more flexible. I bought the digital model about 10 years ago.

Ok thanks

I am not sure what you are referring to.

This

Originally Posted by Big Daddy

B&K makes good products. You won't gain anything with a Radio Shack model. If you don't have the manual, here is a copy.
http://www.bnl.gov/esh/shsd/sop/PDF/IH96500.pdf

[Big Daddy]

B&K makes good products. You won't gain anything with a Radio Shack model. If you don't have the manual, here is a copy.

He already owned a B&K SPL meter. He wanted to buy a Radio Shack SPL meter because he thought he was missing something. That is why I told him that he will not gain anything extra since he already owned another SPL meter.

[triple-x]

nice thread man!

[Big Daddy]

Originally Posted by triple-x

nice thread man!

Thanks. Do you use an SPL meter?

[Clapton101]

I used the Digiatal one from Radio Shack on my Yamaha V463 i first used the min that came with it and then used the SPL meter. I just bought me a new Pioneer Elite and did the same thing except, the mic setting were WAY WAY of from the spl meter. The Auto setup on the Elite had everything in the -#'s like -5.5 for example and when i used the spl meter i had to crank it way up, but when i used the DVE test noise i had to crank it up too much so what i did was use the SPL meter and the test noise on the avr. to get a happy medium. Is the something i did or did not do , It sounds good now but if it can be better i want it to be, but why would this have happened?

[Big Daddy]

Originally Posted by Clapton101

I used the Digiatal one from Radio Shack on my Yamaha V463 i first used the min that came with it and then used the SPL meter. I just bought me a new Pioneer Elite and did the same thing except, the mic setting were WAY WAY of from the spl meter. The Auto setup on the Elite had everything in the -#'s like -5.5 for example and when i used the spl meter i had to crank it way up, but when i used the DVE test noise i had to crank it up too much so what i did was use the SPL meter and the test noise on the avr. to get a happy medium. Is the something i did or did not do , It sounds good now but if it can be better i want it to be, but why would this have happened?

There several problems when you are calibrating your audio:

• Unfortunately, most microphones that are included with the receivers are not very accurate and do not have a flat frequency response. That can also be said about some SPL meters.
• Receivers generate pink noise to calibrate the audio. Pink noise has the same distribution of power for each octave, so the power between 0.5Hz and 1Hz is the same as between 5,000Hz and 10,000Hz.
• It is quite normal to get different SPL readings for different frequency test tones as they react differently with the room boundaries.
• When you use the pink noise from your receiver to adjust the subwoofer level, you will not get accurate results. The main reason is that your calibration program or the SPL meter (if you are using one) measure the peak frequency generated by the sub at that listening position and all other frequencies are ignored. This is why it is best to use test tones and an SPL meter for a subwoofer calibration.
• Receivers' calibration programs try to equalize the sound to your speakers. Unfortunately, they are always successful. To do that with an SPL meter requires an external 1/3 octave graphic equalizer or a parametric one.
• Never trust a computer or a software program. Trust your ears. The best audio is what sounds the best to you.

These are some guidelines for adjusting your audio manually:

• The most troublesome of all speakers is the subwoofer.
• To calibrate the subwoofer, adjust the volume so that the SPL meter reads 75dB with a 50Hz tone at the listening position. Do not play the test tones too loud as this may damage your speakers. Take measurements of four different tones 1/3 octave above the crossover point and four different tones 1/3 octave below the crossover point. Average together each set of four measurements and adjust the subwoofer’s volume level to match the other speakers. Using the receiver's test tones is less accurate as they are not in one-third octave increments.
• To adjust the crossover, run the test tones for intervals between 30Hz to 200HZ and listen to the output level or measure it with an SPL meter. If different output levels are heard or read by the SPL meter for different frequencies, it is quite normal as different frequencies interact differently with the room acoustics. Increase or decrease the low-pass frequency to achieve the smoothest response. Decrease the crossover frequency if there is too much output around the crossover point, increase it if you notice a drop in the response.
• To set the phase, you should set the phase (polarity) of the subwoofer(s) to deliver the highest output at the listening position. This can be achieved with the help of a test signal at the crossover frequency and an SPL meter. You should run this test several times by changing the polarity of the subwoofer and measuring the bass response on the SPL meter. Select the phase option that results in the highest bass response. If you don’t have an SPL meter, you will have to trust your ears.
• If the main speakers are producing bass at the same time as the subwoofer, at some points the bass will reinforce each other. At other points the bass will cancel each other. The solution is to allow only the subwoofer to reproduce bass by setting the front speakers to small in the receiver’s setup menu. This can yield a smoother bass response throughout the entire room.

[Clapton101]

i have Klipsch Rf-82's for fronts RC-62 and Rs-52 and RW-12d Sub. So should i set the 82's to small as well as the surrounds? This is the only way to make bass only come from the sub, I have a Pioneer Elite VSX-91TXH talking about bass i tried to hit the tone button and turn the bass down on the speakers but it wont let me access it.

[Big Daddy]

Originally Posted by Clapton101

i have Klipsch Rf-82's for fronts RC-62 and Rs-52 and RW-12d Sub. So should i set the 82's to small as well as the surrounds? This is the only way to make bass only come from the sub, I have a Pioneer Elite VSX-91TXH talking about bass i tried to hit the tone button and turn the bass down on the speakers but it wont let me access it.

Set your surrounds to small. For the fronts, try them both ways and see which way sounds better. I have the Definitive Technology super tower speakers for the fronts. They have 15" powered subwoofers inside. For music, when I set them to small, the crossover to 40-50 Hz, and have my two external subwoofers generate the bass, I believe the music sounds better. Setting the front speakers to small is not a reflection on the quality of your speakers. It is simply a way of making your multiple speakers work better together in a small home theater room.

I don't understand the second part of your question. What do you mean by setting the tone button? Are you referring to the bass and treble settings on the receiver? If that is what you mean, leave them to neutral. Adjust the volume of the subwoofer by setting the volume knob on the back of your subwoofer to a level between 1/2 and 3/4. Then, in the receiver's menu, adjust the subwoofer setting by increasing or decresing the db level.

[Clapton101]

That is what i was talking about sorry, on the sub i have the volume on like
-16 and the avr sub volume is on like -5 and there is still a whollata bass. when i turn it up to were the spl meter reads 75 sometime it is way too much bass. Is that b/c i have bass coming out of my towers as well and should set them to small like you were saying? Sorry for all the questions.

[Big Daddy]

Originally Posted by Clapton101

That is what i was talking about sorry, on the sub i have the volume on like
-16 and the avr sub volume is on like -5 and there is still a whollata bass. when i turn it up to were the spl meter reads 75 sometime it is way too much bass. Is that b/c i have bass coming out of my towers as well and should set them to small like you were saying? Sorry for all the questions.

If you believe there is too much bass, turn it down. This is the nature of low frequency sounds in a small room. If you move even a few inches and read the spl meter, you will be surprised that the SPL reading for the subwoofer changes quite a bit. This is because of standing waves that are created with low frequency sounds.

You may have to move your subwoofer around and tweak the settings to get good bass sound. At best, you will be able to get good bass sound for one listening position. To get a more even bass sound across the room, you may need two subwoofers that are generating bass frequencies from different locations. Some people use up to 4 subwoofers to even out the bass across the room for all listening positions.

Read A Guide to Subwoofers and A Guide to Subwoofers (Part II): Standing Waves and Room Modes. Part II is particularly helpful in making you understand what goes on with bass frequencies in a home theater room. It is long and a bit difficult to fully understand, but try your best. Be patient and read it carefully. I guarantee that you will have a better unstanding of standing waves. It took me about two months to do the research, create all the diagrams, and write it.

[saprano]

This has been bothering me for awile.

By having my fronts at 150hz and the LPF at 120hz does that leave a hole?
im using the LFE on my sub (which goes up to 150 on the sub itself) so everything is handled by the receiver, from what i've learned i always thought it didn't? the subwoofer is its own channel it doesn't affect anything else.

I was sure thats how it worked but reading around different forums made me curious again.

Also big daddy do you know where i can get tones from 20hz to 20khz? i want to do a test in the center channel.
i have the real traps 10hz to 300hz tones is that enough for high frequency test?

[Big Daddy]

Originally Posted by saprano

This has been bothering me for awile.

By having my fronts at 150hz and the LPF at 120hz does that leave a hole?
im using the LFE on my sub (which goes up to 150 on the sub itself) so everything is handled by the receiver, from what i've learned i always thought it didn't? the subwoofer is its own channel it doesn't affect anything else.

I was sure thats how it worked but reading around different forums made me curious again.

Also big daddy do you know where i can get tones from 20hz to 20khz? i want to do a test in the center channel.
i have the real traps 10hz to 300hz tones is that enough for high frequency test?

I am assuming that your speakers are connected to the receiver correctly and you have your subwoofer connected to the LFE output of your receiver.

1. On the subwoofer, turn the crossover frequency all the way up to the maximum point. You should let the receiver set the crossover. Remember that crossover settings are not precise and exact points. It is a rolloff point where the receiver rolls off the specific frequency. There may still be a leakage.
2. Turn the volume on the subwoofer to a point between the middle and the three quarter point. You can adjust it a little bit later.
3. In the bass management menu of your receiver, set all your speakers to small.
4. The crossover frequency should be set around 80Hz to 120Hz. 150Hz is a bit too high. Experiment and see which one is more satisfactory. Go back to A Guide to Subwoofers thread and read the section on crossover settings.

You can download free test tone generators from the following sites:
http://www.realtraps.com/test-cd.htm
http://www.cleansofts.com/softdownlo...Generator.html
http://www.tasignal.com/Software/MiniDSGe.html
http://www.nch.com.au/tonegen/index_b.html

[saprano]

Yes my sub is connected using the LFE input.

my subs setting are bypassed and the LPF in the receiver is at 120hz

Audyssey set my LCR speakers to150hz, alot of people told me thats to high but chris from audyssey over at AVS told me it sets everything based on your room and speakers.
i'll bring it down to see how it sounds but wont i get dip in the response?

So even with a Xover higher than the LPF on my sub i wont have a hole?

[Big Daddy]

Originally Posted by saprano

Yes my sub is connected using the LFE input.

my subs setting are bypassed and the LPF in the receiver is at 120hz

Audyssey set my LCR speakers to150hz, alot of people told me thats to high but chris from audyssey over at AVS told me it sets everything based on your room and speakers.
i'll bring it down to see how it sounds but wont i get dip in the response?

So even with a Xover higher than the LPF on my sub i wont have a hole?

No, you are ok. Don't worry about an audio hole. If you want you can lower the LPF a little bit.

150Hz crossover puts too much stress on the subwoofer and makes you hear where the bass sound is coming from. No software program can do what your ears can do. Do it the way you like it and the way it gives you maximum satisfaction. After all, this is what entertainment is all about. This is not meant to be a science experiment.

[JasonR]

I would leave your LPF at 120Hz, reduce your xover to 80-120Hz, and crank the xover on your sub all of the way up.

[saprano]

Originally Posted by Big Daddy

No, you are ok. Don't worry about an audio hole. If you want you can lower the LPF a little bit.

150Hz crossover puts too much stress on the subwoofer and makes you hear where the bass sound is coming from. No software program can do what your ears can do. Do it the way you like it and the way it gives you maximum satisfaction. After all, this is what entertainment is all about. This is not meant to be a science experiment.

Ok i'll lower my fronts and center to 120hz and see how it sounds, thanks for your all your help so far.

Originally Posted by JasonR

I would leave your LPF at 120Hz, reduce your xover to 80-120Hz, and crank the xover on your sub all of the way up.

Yea the nob on my sub is turned all the way up to 150hz but im using the LFE input so every is bypassed and the onkyo handles it. which only goes up 120hz, thanks.

[Big Daddy]

A Short Comment on Creating an Audio Hole

A low-pass crossover frequency will block high frequency sound above the cutoof level. A high-pass crossover frequency will block frequencies below the cutoff level.

If you adjust the low-pass frequency of the subwoofer too far below the high-pass frequency, you could end up with a "hole" in between the low-pass and high-pass frequencies.

However, remember that crossover networks cut frequencies progressively. As a result, if, for example, the high-pass frequency for the small speakers is set at 100Hz, and you set the low pass frequency around 80Hz or 90Hz, you will most likely be ok. If, however, you set the low-pass frequency around 60Hz to 70Hz, then you would most likely end up with an audio hole. Can you really hear the difference? I will leave the decision up to you.

[acritzer]

Equipment details:
-Onkyo HT-R520 receiver
-Panasonic BD55K

Hooked up with both a digital optical (for DVD/CD) and 5.1 multi-channel analog (for lossless blu-ray).
Having the normal issues with finding correct levels especially with dialogue. Questions:

1) Using an SPL meter will help get accurate speaker levels, correct?
2) Having used an SPL, did you find that the levels were a lot different than what you had previously set?
3) Having used an SPL, did you still find the need to adjust the center speaker for dialogue issues, and/or turn on dialogue enhancement?

Thank you for whatever advice you offer. I'm just trying to decide if getting an SPL would be beneficial, or if I should just continue to guess and/or fiddle with it for every movie.