Home Theater Forum and Systems banner

1 - 5 of 5 Posts

·
Premium Member
Joined
·
1,538 Posts
Discussion Starter · #1 ·
Hey guys, I've looked at several threads, but everyone seems to have a laptop: I don't. So I'm confused on exactly what equipment I need to purchase to get up and running REW, particularly with capability to do waterfall plots. What I do have is a desktop computer with Asus Xonar DS 192khz/24bit soundcard along with an analog Radio Shack sound level meter, that's it. I think that I can use REW now by connecting the RS meter with a really long (stereo rca?) cord, but that will only give me freq response plotting ability to 3khz, correct? Furthermore, I'd really like to run REW with waterfall plots, whether that is advised to be done later with more experience, I don't know. I think that to do waterfall plots I'd need a calibrated mic (from Parts Express?), long XLR cable, and some form of phantom power supply to power it, possibly this Behringer? Am I on the right path? Or am I missing something?
 

·
Super Moderator
Joined
·
9,285 Posts

It’s no problem using a desktop for REW. The requirements are the same: A sound card with line inputs and line outputs (you can’t use a mic input). That can be the internal soundcard, if it meets the requirements.

Yes, the RS meter is only accurate up to about 3 kHz or so. That’s fine for generating waterfall graphs, as they typically are only relevant below ~300 Hz or so.

Regards,
Wayne
 

·
Premium Member
Joined
·
1,538 Posts
Discussion Starter · #3 ·
Thanks Wayne. So a microphone isn't required to do waterfall graphs? I thought a mic would be needed for sure for the sensitivity; if not, why are calibrated mic's used if a spl meter does the same thing? Are they only valuable for higher freq's? And if that is the case, I guess it is imperative that the mic be (properly) calibrated since I'm seeing that measuring the upper freq are extremely sensitive.

If all I need is the spl meter, why haven't I been using REW all along? I kept seeing posts/threads about mic's and external devices, etc and was put off because of the cost as some of the devices mentioned in posts run $150+
 

·
Registered
Joined
·
678 Posts
... So a microphone isn't required to do waterfall graphs? ...
Well, obviously the RS meter itself includes a microphone. But, yes, a separate microphone is not required for doing waterfall charts in the bass and mid-bass range.

... if not, why are calibrated mic's used if a spl meter does the same thing? Are they only valuable for higher freq's? ...
I bought a calibrated mic to verify some changes at high frequencies with the crossovers in my mains. At the low end, below ~20Hz, you start to see manufacturing variation between mics become a factor, so some people use a calibrated mic to obtain accurate measurements down to 10Hz. Usually one looks at waterfalls to adjust speaker position and perform room treatments, which don't need measurements at such low frequencies.

Have fun,
Bill
 

·
Super Moderator
Joined
·
9,285 Posts

why are calibrated mic's used if a spl meter does the same thing? Are they only valuable for higher freq's? And if that is the case, I guess it is imperative that the mic be (properly) calibrated since I'm seeing that measuring the upper freq are extremely sensitive.
The SPL meter is only good up to ~3 kHz. Our calibration file for the RS meters are generic and can’t be completely accurate from one meter to the next. This is why mic with a custom calibrated can take accurate full range measurements. Even the lower frequency measurements will be more accurate.


If all I need is the spl meter, why haven't I been using REW all along? I kept seeing posts/threads about mic's and external devices, etc and was put off because of the cost as some of the devices mentioned in posts run $150+
Can’t answer that one for you. The REW Cabling and Connection Basics sticky thread and the REW Help Files are pretty plain in showing that the SPL meter and a USB sound card w/ line inputs and outputs are all that REW requires for basic low frequency measurements. :)

Regards,
Wayne
 
1 - 5 of 5 Posts
Top