Speaker measurement tools

[westend9]

I would like to enter the speaker measurement universe and have nothing other than a JBL 5860 mixer that is probably not going to add much to the effort. I have been looking at mic's and sound card processors but haven't made any decisions.

What would be a good entry level set of gear to measure speaker response?

[bfish]

"Entry level" can get you in trouble unless you just want to use it once or twice. You can start with an onboard soundcard, compatible mic, and freeware. If you're like most of us though, a little info just makes you more curious, and soon the limited capability/accuracy of entry level doesn't get it anymore. I went through several upgrades just trying to have enough to get by the task at hand, and wasted a lot of dough getting there. I'd have been many dollars and headaches ahead to jump in the deep end first.

The deep end doesn't have to hurt too bad though. Around $300 for hardware and the same or less for software should get you there. Another $150 for a WT2 to do TS specs if desired. Since my gear is a few years old and I know there is newer/better out there now, let those that have been in the market recently point the way.

[westend9]

Thanks guys, good info, so far. I was looking at the Behringer ECM8000. Do you think a calibration is necesary?
What are the advantages of the M-audio product? As for phantom power, can this be as easy as just providing a power source? I do have some stand-alone power supplies in the 24v.-30v. range.
I'll take Bfish's advice on not trying to bottom-feed this to fruition. I've learned the hard way about not having good tools. I will probably start with one of the freeware software products just to get my feet wet, though.
I would like the gear to be able to interface with a laptop, for convenience. What is the typical connectivity, USB?

[bfish]

Thanks guys, good info, so far. I was looking at the Behringer ECM8000. Do you think a calibration is necesary?
What are the advantages of the M-audio product? As for phantom power, can this be as easy as just providing a power source? I do have some stand-alone power supplies in the 24v.-30v. range.
I'll take Bfish's advice on not trying to bottom-feed this to fruition. I've learned the hard way about not having good tools. I will probably start with one of the freeware software products just to get my feet wet, though.
I would like the gear to be able to interface with a laptop, for convenience. What is the typical connectivity, USB?

I use an off-the shelf ECM-8000, but I preload the provided calibration file. There's certainly nothing wrong with calibration, every aspect of the hardware should be calibrated. You'll end up testing your testing system in order to trust it.

Integral phantom power can't be beat, especially for laptop/portable use.

USB 2.0 or Firewire ports offer the needed bandwidth.

The specs of your external card determine the resolution of your test. Pay close attention to the duplexing ability (simultaneous input/output), many units say "full duplex", but when you read the fine print, they only duplex at low to medium bit rates.

[westend9]

There are some reports (from reliable sources) that WT2 may still be the preferred option;

WT-3 testing of 2204, Fs higher in sealed box???

Which brings up another point. Test results are only as good as the gear, the procedure, and the interpretation of the results. It's a real treat that DIYers can now get the info they need, but bad info is worse than no info.

For example, TS specs can vary widely depending on the position and securing method (or not) of the driver. Indoor acoustic tests will have all sorts of false data unless the software has "windowing" ability to catch only the direct sound and shut off before any reflected sound arrives, and the user must set the appropriate parameters based on mic placement and distance to reflective surfaces. There's plenty of bad data posted online to prove it. Bottom line, read the book and follow the instructions.

I was wondering about the reliability of test results when doing "in room" setups. It would seem that any reflections (or absorbtions) are going to foster inaccuracies. Hell, I'll get my buddy that used to eat his lunch in the Bose anechoic chamber to help me set up something, lol (as long as we don't end up with something Bose-like).

I use an off-the shelf ECM-8000, but I preload the provided calibration file. There's certainly nothing wrong with calibration, every aspect of the hardware should be calibrated. You'll end up testing your testing system in order to trust it.

Integral phantom power can't be beat, especially for laptop/portable use.

USB 2.0 or Firewire ports offer the needed bandwidth.

The specs of your external card determine the resolution of your test. Pay close attention to the duplexing ability (simultaneous input/output), many units say "full duplex", but when you read the fine print, they only duplex at low to medium bit rates.

Great information, this is just the kind of things I need to know. Thanks!

Are there any sound cards that are better at testing than just doing audio? Or, are the sound cards that have a good set of DAC's good at both? I'm looking for cross-purposing or lack of that, here.

[bfish]

There are (or at least used to be) externals made explicitly for testing, but waay more expensive. Consumer cards for music usually have little need for simultaneous input and output, you're usually either playing or recording, but not both at the same time. That's where the duplexing factor comes in for testing, you're sending a signal and listening for the real-time response at the same time.

The Edirol FA-66 I use was made for multi-channel recording, and the live monitor function allows 24/96 duplexing.

Speaking of real-time, latency is a term to learn and understand how it applies to your hardware;

http://en.wikipedia.org/wiki/Latency_(audio)

With that in mind, time-sensitive data loops on Windows platforms benefit from hardware using ASIO drivers in place of the std WDM.

[Panomaniac]

One of the M-Audio USB cards will be just fine and dandy. Just be sure you get one with phantom power if your mic needs it. If it doesn't - I have one to sell you.

[bfish]

...And another $100 for the WT3 woofer tester with scale...

There are some reports (from reliable sources) that WT2 may still be the preferred option;

WT-3 testing of 2204, Fs higher in sealed box???

Which brings up another point. Test results are only as good as the gear, the setup procedure, and the interpretation of the results. It's a real treat that DIYers can now get the info they need, but bad info is worse than no info.

For example, TS specs can vary widely depending on the position and securing method (or not) of the driver. Indoor acoustic tests will have all sorts of false data unless the software has "windowing" ability to catch only the direct sound and shut off before any reflected sound arrives, and the user must set the appropriate parameters based on mic placement and distance to reflective surfaces. There's plenty of bad data posted online to prove it. Bottom line, read the book and follow the instructions.