# Can I use a Zoom H4N as an REW interface?



## Aujan (Feb 13, 2011)

Can I use a Zoom H4N as an REW interface? I think that the H4N only has ASIO drivers, which
lots of programs don't like. I seem to remeber seeing something about java script not working with ASIO.

Has anyone tried this? If so, how did it work? Thanks.


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## mechman (Feb 8, 2007)

Why don't you try it out and let us know? :T


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## Aujan (Feb 13, 2011)

mechman said:


> Why don't you try it out and let us know? :T


If no one has done it, I'll try it out and I'll do a complete report. My time is very constrained right now though,
but I'll be glad to post details about it once I try.


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## mechman (Feb 8, 2007)

I did a quick search here and found this thread. Maybe that will help? Sounds like it may not work since you need a calibration file.


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## Aujan (Feb 13, 2011)

mechman said:


> I did a quick search here and found this thread. Maybe that will help? Sounds like it may not work since you need a calibration file.


Thanks for the info, I read the thread. My issue is not the H4N internal mic. you can use the H4N as a pre amp with 48 volt phantom, so I can use any mic I wish. I need to know if REW will recognise the H4n ASIO driver so I can use the H4n as a USB inerface.

I'm going to set up REW with the computer sound card line in and a RS SPL meter just to verify function.
Then I'll try to install the zoom and I'll report back my findings. If that works, I'm going to get/write a cal file for my AKG 414 B-ULS and take readings with that. I'll report my findings on that as well.

I have an IVIE system at work. Maybe I can borrow it and compare and post the results.
But first I need to get REW up and running!


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## JohnM (Apr 11, 2006)

REW does not support ASIO (yet), you need WDM drivers for Java to see the interface. Built-in line inputs and outputs are generally perfectly OK though.


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## Aujan (Feb 13, 2011)

Update 3-6-11

I had a minute, so I plugged in my h4n into my USB port and selected the "interface" option.
Windows asked if I wanted to install the driver, I hit yes. It installed my H4n with no need
for downloaded drivers.

I booted up REW for the first time, and went to the preferences page.
to my surprise, the H4n was there in the list of devices, so I selected it as my input 
and output device, choosing "mic" as input and "headphone" as output.

I set the H4n to phantom power, and hooked up an AKG 414 B-ULS in omni mode.
I fired up the spl function in REW, and I got a reading. I put my RS SPL meter right next to the 414,
and the readings seem spot on.

So I guess that I'll have to read up on REW now so that I can calibrate this setup and try some readings.
I don't want to get too happy too soon, but I think that this H4N may very well work as a usb soundcard
for REW.

If things work out, I'll bring home an earthworks mic from work and compare it to the AKG.
More to come...


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## Aujan (Feb 13, 2011)

Update 3-9-11

My H4n calibration is skewed. Looks like a feedback loop, but all monitoring is off.
I went into every mode and shut it down just to be safe, but to no avail.

If you look at levels, and turn monitoring "on" they jump right up into distortion,
like a good feedback loop should  If you disable monitoring, the levels settle
in within .2 db nicely.

Any ideas?

I'm trying to update my H4n's firmware.


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## JohnM (Apr 11, 2006)

Can you post screenshots of the frequency response and impulse response? The Windows mixer playback level settings would also be useful.


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## Aujan (Feb 13, 2011)

JohnM said:


> Can you post screenshots of the frequency response and impulse response? The Windows mixer playback level settings would also be useful.


Hello John, thanks for jumping in!

I just figured out how to post a pic. I'll do it when I get access to that computer.

The H4n doesn't use the windows mixer, except for the output level. (as far as I can tell).
The output is at full. I did play with the input/output settings on the H4N to get the best looking
response. 

I do have a "REW newbie" question though 

I noticed that when I zoom out all of the way, ( I think that it takes 7 or 8 clicks) that the curve resembles 
a flat response with some apparitions in the upper frequencies. So I'm wondering if by default I'm zoomed in
really close to the trouble spots ??? Should it look flat with the default view?

Thanks.


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## JohnM (Apr 11, 2006)

If you zoom out far enough almost anything looks flat 

When looking at a loopback result only the ripples of the soundcard's output filter and the roll-off at the low end should be affecting the response. The ripple should be less than 1 dB, so a fairly narrow SPL range of about 6dB is normally used for that measurement. For room measurements the range would normally span 60dB.


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## Aujan (Feb 13, 2011)

>If you zoom out far enough almost anything looks flat < That's too funny! I suppose so.

I had some time to play with the software on a loner computer with a soundcard that had a line in/out.
After spending some time solving mixer problems (this card had it's own record volume that was separate from the main mixer, hidden in the control panel/audio devices tab) I was able to easily get that card to calibrate, and see what it should look like. So now I know for sure that I have serious problems!

Here's the snapshots that I grabbed last night. I didn't know enough to "standardize" the image/scale last night, but I think that you'll get the general idea. Any thoughts? It seems to be ringing at harmonic octaves.


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## JohnM (Apr 11, 2006)

It looks like the effect of small interruptions in either the generated or captured signals. Increasing the buffer size settings on the REW Soundcard preferences may help, also try playing back a tone to see if it plays without interruption.


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## Aujan (Feb 13, 2011)

Thanks for the ideas, that's great news if it's just a signal glitch. I think it's the output, as it's just a headphone out, and the system's weak link. I have a good quality Fosstex TT15 test gererator with 0dbv (1 volt), -10dbv (316mv) and -30 (31.6mv) output with 40 hz,400hz,1k,10k,15k tones.Can I use that to test or calibrate my card?

I'll try what you suggested, and I'll report back. I think that you are on the right track because
I was able to remove most of the distortions by playing with the zoom's input/output levels.

I do remember monitoring the test tone and it stammeredd a bit, but I cleaned it up somewhat
with adjustments. I'll try the buffer size, and I'll also try the H4N on another faster computer.
I'm happy to be able to think that there's hope with this card!

More to come...


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## Aujan (Feb 13, 2011)

Tried everything, all to no avail. I even went into the audio devices tab and shut down mixer operation
for the H4N. Same result. I did a quick calibration using only the computer's on board sound card, and that worked fine. The problem is that I need it to be mobile, and it's a desktop PC. I have a laptop with a mic input that I _think_ I can switch over to a line device. That will have to do for now.

I still want to solve this perplexing problem. I even tried using the computer's sound card as my output device, and the H4N as the input device, same result. Here a snapshot of the calibration in the oscilloscope window:


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## spinnaker (Aug 6, 2011)

Can you plug a line level signal directly into the 3.5mm stereo mic input?

Does anybody sell the H4n with a calibration file?


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## Aujan (Feb 13, 2011)

I was never able to get the H4N working. I just bought a high end AD/DA. It's not a Home theator device, it's a pro audio interface made by RME. When I get some time I'll post compatibility.


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