Best USB sound and midi module including Phantom mic input !

**m-fine** · **03-17-08, 09:02 AM**

JP, when you get a chance, can you please post a graph of the sound card calibration from about 5 hz to 100 or 200. I am interested in this unit but I would like to minimize the ammount of correction I am adding down deep relative to the measured signal.

Thanks

**stevenkelby** · **03-19-08, 08:26 AM**

I stopped getting notifications for this thread for some reason. I am getting a Fast track pro and ECM8000 now thanks partly to this thread.

JP, does the midi interface work to send a signal to other units, or only the DSP1124 ?

I am thinking of a Rane RPM26Z to EQ my whole system, not just subs as most people here seem to do. Do you EQ your full system?

I've started the REW help files but read slow.

Thanks,

Steve.

**m-fine** · **03-19-08, 08:56 AM**

As the frequency gets higher, the peaks and nulls affect smaller and smaller areas, or in other words the variation from seat to seat become greater. For that reason I think room treatments are a better solution above 100 hz or so, and any EQ used to treat resonance above a few hundred hz can make things much worse for those not sitting exactly where the mic was. You can still use full range EQ to do things like gently roll off the high frequencies (upper end house curve) but I would not attempt to flatten out the room response.

**stevenkelby** · **03-19-08, 09:05 AM**

Quote:

m-fine wrote:

As the frequency gets higher, the peaks and nulls affect smaller and smaller areas, or in other words the variation from seat to seat become greater. For that reason I think room treatments are a better solution above 100 hz or so, and any EQ used to treat resonance above a few hundred hz can make things much worse for those not sitting exactly where the mic was. You can still use full range EQ to do things like gently roll off the high frequencies (upper end house curve) but I would not attempt to flatten out the room response.

Thanks for that. So do you still measure the mid and high frequencies to know what kind of room treatment to do, or is it normal just to use generic treatments like panels at 1st reflection points etc?

JP, sorry for going OT!

**imbeaujp** · **03-19-08, 02:29 PM**

Quote:

stevenkelby wrote:

I stopped getting notifications for this thread for some reason. I am getting a Fast track pro and ECM8000 now thanks partly to this thread.

JP, does the midi interface work to send a signal to other units, or only the DSP1124 ?

Steve.

This is a midi interface, so it works with any midi device supported by REW.

**m-fine** · **03-19-08, 04:40 PM**

Quote:

stevenkelby wrote:

Thanks for that. So do you still measure the mid and high frequencies to know what kind of room treatment to do, or is it normal just to use generic treatments like panels at 1st reflection points etc?

JP, sorry for going OT!

Normally you use generic treatments in the corners and on any large reflective surfaces you can get away with treating. Putting a panel at the first reflection points has other benefits but the impact on resonace is not much different than other reflective locations. You may want to just treat the room and measure the change with your ears. If you measure accurately in 1/48th octave detail, you will end up seeing how bad your room response really is which is usually not comforting since it is nearly impossible to completely fix. Ignorance is bliss here.

**Dundas** · **03-19-08, 05:37 PM**

Tascam seems to have similar products (US122-L & US144) that sell for a little less. They aren't Vista compatible is the M-Audio?

http://www.tascam.com/catalogue;40,15.html

**bwana** · **04-02-08, 08:52 PM**

i decided to go with the m-audio fast track pro. i will be using it for other things as well, but for this project (analyzing a car or a room audio system) it will work well with a behringer mic. I read the bit about calibrating a pc - TRUE RTA for dummies (http://www.avsforum.com/avs-vb/showt...=572477&page=6) but am a little confused because of the multitude of in/outputs on the fast track pro. there are 2 balanced inputs for 2 microphones. these inputs are actually combo jacks that accomodate either an xlr(for a mic) or a TS(for a guitar or keyboard)

i assume to calibrate this device, i would need to go from the balanced trs outputs to the balanced mic inputs, yes? this would require male TRS-> male XLR

Or should i go this way: rca output -> TS male mic connection?

or should i go from headphone jack->splitter-> 2 TS male mic connections

what about the voltages-if i use the headphone vs balanced out(TRS) vs unbalanced out(rca) and pipe that into the microphone input---wont i blow the mic input? after all the real microphone usually does not supply voltage and phantom power is coming out of the microphone jack. In setting up a calibration loop, we are piping voltage into the microphone circuit.

**brucek** · **04-02-08, 09:36 PM**

Quote:

assume to calibrate this device, i would need to go from the balanced trs outputs to the balanced mic inputs, yes?

Nope. You don't include the mic preamp section in the soundcard calibration. You connect from line-out to line-in. The small difference the mic section makes is not significant.

brucek

**bwana** · **04-02-08, 09:44 PM**

line out and line in on the pc are not used--the m-audio device hooks up via usb. i am asking which out/inputs on it are used to create the loop for calibration.

**glaufman** · **04-03-08, 07:44 AM**

Quote:

bwana wrote:

line out and line in on the pc are not used--the m-audio device hooks up via usb. i am asking which out/inputs on it are used to create the loop for calibration.

I'm pretty sure Bruce doesn't mean to use the line in/out on the pc, but rather line in/out on the m-audio... specifically, the unbalanced ones...

I didn't read much above to see exactly what you're doing, but assuming youp're looking to run scans the way most of us do, albeit in your car, I think you'll want to send REW's (or TrueRTA's for that matter) output to your system via the line out (unbalanced) on the m-audio, so this way to capture that output's characteristics in the calibration file.

Bruce's point is that then switching from the unbalanced line in to the balanced "mic" in with the phantom power will introduce errors, but so small as to be negligible...

It certainly looks (from the specs) that the balanced input on the m-audio cannot handle the full scale input from it's own balanced output...

**brucek** · **04-03-08, 07:55 AM**

Quote:

I'm pretty sure Bruce doesn't mean to use the line in/out on the pc, but rather line in/out on the m-audio... specifically, the unbalanced ones...

Exactly.....................

brucek

**bwana** · **04-03-08, 09:52 AM**

Quote:

glaufman wrote:

I'm pretty sure Bruce doesn't mean to use the line in/out on the pc, but rather line in/out on the m-audio... specifically, the unbalanced ones...

I didn't read much above to see exactly what you're doing, but assuming youp're looking to run scans the way most of us do, albeit in your car, I think you'll want to send REW's (or TrueRTA's for that matter) output to your system via the line out (unbalanced) on the m-audio, so this way to capture that output's characteristics in the calibration file.

Bruce's point is that then switching from the unbalanced line in to the balanced "mic" in with the phantom power will introduce errors, but so small as to be negligible...

It certainly looks (from the specs) that the balanced input on the m-audio cannot handle the full scale input from it's own balanced output...

EXACTLY! and yes tnx bruce.

to summarize, i have 2 choices for a calibration loop-
1)unbalanced rca out to TS input in the combo jack
2) trs balanced out to xlr in into combo jack

Obviously the measurements will be done with the rca out to the line in of the head unit and the mic will be xlr. so it seems from the above discussion that the appropriate calibration loop is #1 above. yes?

**glaufman** · **04-03-08, 02:52 PM**

**bwana** · **04-03-08, 08:45 PM**

well , i did that and i followed the true RTA guide for dummies at the avsforum (audio setup section) i got a jiggly line that sort of trended up but a few secs later became flatter. nothing like the smooth line in the tutorial.

**glaufman** · **04-04-08, 08:14 AM**

Quote:

bwana wrote:

well , i did that and i followed the true RTA guide for dummies at the avsforum (audio setup section) i got a jiggly line that sort of trended up but a few secs later became flatter. nothing like the smooth line in the tutorial.

You got a "jiggly line" in TrueRTA or REW? Although I've played around with TrueRTA (the free, 1 octave resolution version) I'm not very familiar with it... but unlike REW, it only works as an RTA, so you have to let it average over time before you get anything significant...

Why not try using REW and see what results you get?

**stevenkelby** · **04-04-08, 11:05 AM**

Thanks for the info.

Quote:

glaufman wrote:

It certainly looks (from the specs) that the balanced input on the m-audio cannot handle the full scale input from it's own balanced output...

So what units can? What are the competition/alternatives?

**glaufman** · **04-04-08, 05:06 PM**

Quote:

stevenkelby wrote:

Thanks for the info.

So what units can? What are the competition/alternatives?

Dunno... that's one reason to use the line in/out for cal...

**stevenkelby** · **04-04-08, 10:00 PM**

Quote:

glaufman wrote:

Dunno... that's one reason to use the line in/out for cal...

Ah ok, so that would of course correct the error and the fast track pro would be accurate again?

Close to buying one today.

**m-fine** · **04-05-08, 04:11 PM**

Quote:

stevenkelby wrote:

What are the competition/alternatives?

TASCAM US122L if you do not need digial ins and outs TASCAM 144 if you do. Note that the digital outs also can not be calibrated, so are not recomended for REW use.

**stevenkelby** · **04-05-08, 10:49 PM**

Quote:

m-fine wrote:

TASCAM US122L if you do not need digial ins and outs TASCAM 144 if you do. Note that the digital outs also can not be calibrated, so are not recomended for REW use.

Cool thanks.

Amazon.com: Customer Reviews: Tascam US-122L
Didn't have many good reviews on Amazon but I didn't look elsewhere. DO you think it's better than the FTP?

Too late anyway, I just bought a FTP, ECM8000 and CM-130 from Amazon.

Just need a laptop now...

At least I can use the FTP to rip vinyl to digital, will set up the TT on my desk.

**m-fine** · **04-06-08, 08:21 AM**

Quote:

stevenkelby wrote:

DO you think it's better than the FTP?

I think it has less low frequency roll off. I think that is probably better for REW use where you care about the 5-15 hz range since you have a higher ratio of measured signal to calibration correction (mic plus SC), but honestly I am not sure it makes much difference at all. I would love to measure the pre-amp stage on the two units to compare but that is not a simple task.

The TASCAM's had some negative reviews because it took them a VERY long time to get Vista support. As for XP use, the included driver works fine. Plug in in and go. The unit seems very solid with an aluminum body and low profile dials that should survive in a gear bag. I can not comment on the other software provided because I only use mine for REW and as a USB sound card/headphone amp.

**brucek** · **04-06-08, 08:24 AM**

Quote:

I would love to measure the pre-amp stage on the two units to compare but that is not a simple task.

Why is it not simple? Instead of a loopback cable on the right channel (which would measure as perfectly flat), you include the preamp or any line level device in that loop and take a full range measure. It will show the devices response from 0Hz to 20KHz....

brucek

**m-fine** · **04-06-08, 10:39 AM**

Quote:

brucek wrote:

Why is it not simple? Instead of a loopback cable on the right channel (which would measure as perfectly flat), you include the preamp or any line level device in that loop and take a full range measure. It will show the devices response from 0Hz to 20KHz....

brucek

You have a line level RCA out which you would want to route to a balanced mic level in. Wouldn't you need a device in the middle to convert to balanced? Then you would introduce whatever error that is inherent in that device. If I could just calibrate with an RCA to XLR cable I would, but I thought that was a no no.

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