Author Topic: Sound Level Meter  (Read 5853 times)

Offline Carlman

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Sound Level Meter
« on: June 15, 2012, 07:09:17 AM »
I was looking for an SPL meter and keep finding that most only cover the 'standard' human hearing range, 100Hz or so up to 8kHz.

Here's one with the specs listed:
http://www.amazon.com/Sinometer-JTS1357-Digital-Sound-Level/dp/B00067L420/ref=tag_dpp_lp_edpp_img_in

If I'm trying to find a bass hump at 50Hz, or a weird resonance at 12,k am I out of luck on these things?

I have a hard time believing these high tech meters aren't as good as the ol' Ratshack meters of yore that were $20. 

Anyone know of a meter that measures the standard 20-20 range for hifi gear?

-C
I really enjoy listening to music.

Offline richidoo

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Re: Sound Level Meter
« Reply #1 on: June 15, 2012, 09:39:04 AM »
The rat shack meters aren't accurate in low frequencies either. No dynamic mics are accurate in LF. Condensor  mics are needed for accurate wide band measurements.  In LF, dynamics are OK for relative measurements, like is it louder in this corner than that corner, but the actual readings are not accurate measurements.  Parts express sells an even cheaper one.

This is what you want:
http://www.daytonaudio.com/index.php/omnimic-v2-precision-measurement-system.html

You might need a USB extension cord for your big room.

Offline Carlman

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Re: Sound Level Meter
« Reply #2 on: June 15, 2012, 09:43:09 AM »
I was just looking to play a frequency and walk around the room to see where the humps were...

The RTA system you've linked looks interesting and I might go that route.  I'm not sure what the price includes, though... at $400 it's more than I was looking at... I was thinking $30-100... :*
I really enjoy listening to music.

Offline richidoo

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Re: Sound Level Meter
« Reply #3 on: June 15, 2012, 09:57:15 AM »
Yeah, pricey - if it weren't then I'd own one and you could borrow mine!  :D

You can still use a portable meter to compare relative levels. Louder sounds will have a higher value (duh) so you can still find the humps and dips with it, even though the displayed levels aren't the actual sound pressure.

Offline _Scotty_

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Re: Sound Level Meter
« Reply #4 on: June 15, 2012, 11:31:17 AM »
Carl here is a link to a Ph.D thesis by Adrian Celestinos
which describes the Controlled Acoustic Bass System (CABS).
http://vbn.aau.dk/files/12831869/AC-phd.pdf
This is the way to get out of looking for the humps in your room. Don't create them in the first place.
 I use a modified version of this system in my L shaped room. It works very well and results in a fairly even distribution of bass energy in the room, however the room's L shape makes complete elimination of resonant behavior in the bass frequencies impossible. When the CABS approach is used in a square or rectangular shaped room it can yield virtually perfect nullification of room resonances below the Schroeder frequency.
 Quoting from Adrian Celestinos Ph.D thesis "The system can achieve good responses not only in a single listening position but also in the whole room from 20 Hz to 100 Hz having spatial deviations in a large listening area of only ± 1.3 dB in the ITU Room and ± 1.6 dB in the IEC Room, contrary to the advanced room correction systems that typically optimize to a single listening position.
Scotty

Offline Face

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Re: Sound Level Meter
« Reply #5 on: June 15, 2012, 07:38:25 PM »
I was just looking to play a frequency and walk around the room to see where the humps were...

The RTA system you've linked looks interesting and I might go that route.  I'm not sure what the price includes, though... at $400 it's more than I was looking at... I was thinking $30-100... :*
FYI, it's only $300, not $400.  http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-792