Reference SPL for loudspeaker evaluation?

Archived from groups: rec.audio.tech (More info?)

Hi!

I have made myself an evaluation CD; a CD with snips from my CD
collection that could be used for evaluation of loudspeakers. A good
idea, by the way, that was inspired by some poster here at R.A.T.

I have decided to start the evaluation CD with a reference tone to set
the playback volume equal at every listening session. The problem is,
should I use white noise, pink noise, single frequency or something
else to set the sound pressure level? I have a lot of commercial test
CD:s to choose test tones from.

I have a simple SPL meter at hand, should I set that to linear, dbA or
dBC metering when caibrating the listeing level?

Per.

PS. It was fun to make the collection! It contains solo violin, big
jazz bands, Sheffield drums, "1812" cannons by Telarc and lot's more!

Archived from groups: rec.audio.tech (More info?)

"Per Stromgren" <per.stromgren@telia.com> wrote in message
news:micah0h8qm07mk3t6n8modkomm52ate39c@4ax.com...
> Hi!
>
> I have made myself an evaluation CD; a CD with snips from my CD
> collection that could be used for evaluation of loudspeakers. A good
> idea, by the way, that was inspired by some poster here at R.A.T.
>
> I have decided to start the evaluation CD with a reference tone to set
> the playback volume equal at every listening session. The problem is,
> should I use white noise, pink noise, single frequency or something
> else to set the sound pressure level? I have a lot of commercial test
> CD:s to choose test tones from.
>
> I have a simple SPL meter at hand, should I set that to linear, dbA or
> dBC metering when caibrating the listeing level?
>

Pink noise stimulus and your SPL meter set to linear will get you an
accurate whole spectrum SPL reference.

> Per.
>
> PS. It was fun to make the collection! It contains solo violin, big
> jazz bands, Sheffield drums, "1812" cannons by Telarc and lot's more!
>

Archived from groups: rec.audio.tech (More info?)

On Thu, 02 Sep 2004 20:57:08 +0200, Peter Larsen
<SPAMSHIELD_plarsen@mail.tele.dk> wrote:

>Per Stromgren wrote:
>
>> I have a simple SPL meter at hand, should I set that to linear,
>> dbA or dBC metering when caibrating the listeing level?
>
>Set to SLOW and C, aim for 80 dB in the loud passages, that should keep
>peaks at 105 dB or less and thus keep your ears in their reasonably
>linear range, but verify the capabilities of amp and loudspeaker
>combination, one loudspeaker powered by the amplification used should be
>able to produce 105 dB peak at a distance of 1 meter.

The CD has two track that I put there to be able to calibrate the
level: white noise at -20dBFS RMS and a 1kHz tone at -30dBFS. Is your
suggestion that I calibrate 1kHz at 75dB (equivalent to full scale at
105dB) and hope that 1kHz is not a severe dip or peak? Would white
noise at 85dB be better?
>
>> Per.
>
>> PS. It was fun to make the collection! It contains solo violin, big
>> jazz bands, Sheffield drums, "1812" cannons by Telarc and lot's more!
>
>Did you remember to check whether the source material is clipped ...

I'm not sure I can! Are there any free tools out there, that could do
the job? I now Cool Edit can detect clipping, or guess rather, but I
don't want to buy a license.

Thank's for the comments.

Per.