E-MU 1616M soundcard calibration help needed.

Hi, I purchased an E-MU 1616M cardbus soundcard for my laptop. I also purchased an Apex 220 microphone (requires phantom power) to use along with REW. The 1616M has a microphone input with 48V phantom power so I will be connecting the MIC to that input. The output connections on the rear panel of the 1616m are 1/4" balanced and this where I am confused.
In order to calibrate the soundcard I have to connect the output to the input. In my case, the mic input is XLR or 1/4" and the output is 1/4". Can someone give me detailed instructions to correctly calibrate the soundcard? I haven't purchased a MIC cable yet since it can be connected with either an XLR or 1/4"TRS connector. Can I safely connect the Microphone with a 1/4" connector?Your help would be greatly appreciated!

http://www.emu.com/products/product.asp?product=13552

http://www.emu.com/products/zoom/13552.html

Since you'll be using one of the line-level outputs, you'll need to use the line-level input that is integral to the mic preamp. This will bypass the mic's initial preamp in the loopback, but will include its line amp, but that's fine, there's really no other way to do this.

You see from your manual that to invoke the mic preamp you use an XLR connector, but to use the Hi-Z or Line-in portion you use a 1/4" TRS plug. (Later, when using the mic, use an XLR). (Hopefully you have a calibration file for the microphone)

So you would connect a standard 1/4" TRS (tip, ring, sleeve) cable from one of the 6 line-out connector jacks to the A or B Line/Mic jack. Leave the 48v phantom power switch off for this test.

You will have to be sure that you turn off all the features (i.e. effects, soundfields, eq, etc, etc). You want it in simple 2.0 stereo mode to be used with REW. You'll have to see what channels REW recognizes and select those in the settings page appropriately for input and output.

Like most devices such as this, it will accept balanced or unbalanced, so if you are going unbalanced simply use TS connectors instead.

brucek

Thank you Bruce! I don't have a calibration file for the Apex220. It came with a calibration printout of the response. It's within 1db to 10khz, then it's about 3db out on up beyond 20khz.
http://www.apexelectronics.com/pdfs/omapex220.pdf

I'm still a bit confused as to the different method of connection when it comes to calibration versus actual measuring. The neutrik input has 2 different gain levels depending on what type of connection is used. Are you saying to use a jumper from the line output to the hi-z input and leave the preamp turned off? Then when I actually measure, use an XLR connection to use phantom power? I don't think I can configure the MIC input as a stereo input. The outputs are stereo however.
I'm sorry, I'm new to this and easily confused.

Yeah, the pdf doesn't reveal much as to the accuracy down to 10Hz. This is usually necessary for low subwoofer work. I suspect its fairly flat from 30Hz up to about 10K though.

The manual shows the A and B mic/line connectors as a typical combo XLR and 1/4" jack.
If you use the XLR, it passes the signal through the low level mic preamp and then it would be buffered through a line amp. You use this for the mic.
If you use the 1/4" TRS jack, it supports hi impedance high level inputs from guitars and also standard line-level inputs. It's the line level input you'll be using for the soundcard calibration. Once that's done and you remove the loopback cable, you'll plug in your microphone using an XLR connector and turn on the phantom voltage.

The loopback cable will go from one of the line-out jacks. (it appears these can be set for typical consumer -10dBV or +4dBu pro level in the software setup). I don't know what you'll be feeding these with when you measure so I can't comment there, but in the soundcard calibrate you'll set this output standard and adjust the line-in level accordingly.

Here's the bottom line. Get a cable with 1/4" TRS plugs on each end. Connect it between a line-out and A mic/line-in and do the soundcard cal routine. Remove this loopback connection and plug your mic with its XLR connector into the A mic/line-in and turn on the phantom power. Feed the line-out to your receiver.....

brucek

I will be going from the LINE OUTPUT to a preamp input that has both RCA inputs and XLR. I have the R.Shack#274-884 adapters so are they ok to use with the RCA inputs? What do you mean by "but in the soundcard calibrate you'll set this output standard and adjust the line-in level accordingly"? I thought during calibration I should not use the gain on the HI-Z line input.

Must the jumper have TRS plugs? I ask because I have a jumper with TS connectors. Sorry if these are silly questions Bruce. I'll buy whatever it takes to do the job the correct way.

Hi, anyone willing to answer my last post? I apologize for my ignorance on the subject matter.

Sorry Frank, I was out of town on business.

I see no use for the adapters. The line output on the soundcard is either balanced 1/4" TRS or unbalanced 1/4" TS. That means you have two choices.
1. Cable with 1/4" TRS on one end and XLR on the other end.
2. Cable with 1/4" TS on one end and RCA on the other end.

Your manual shows that you can select the output standard in software between the typical consumer nominal -10dBV (max input =~1.24vRMS) or pro level of nominal +4dBu (max input =~5vRMS). You would set this first depending on the type of preamp you have.
Then, just like any soundcard, during the soundcard calibration you adjust the wave output level and set the input level. You have a manual adjustment on the input level laballed Input Gain. You will need to adjust it to the correct line level (as shown on the REW VU meters during the process). It will be much clearer once you give it a try.

No, you can certainly use 1/4" TS interconnects. The signal will simply be unbalanced. That's fine.

edit: BTW, that's a serious soundcard. What is your application other than REW?

brucek

Hi Bruce, I use it primarily to record vinyl to hi-rez dvd-audio. I just got it last week and there's a lot to learn. It was a real pain trying to find a laptop with a cardbus slot since they all use express now. Anyway I recorded a few needledrops over the weekend and they came out quite nice. Now the challenge is to be able to get some room measurements.

Let me see if I have this correct.
Calibration: Set the card input level to unbalanced (consumer). Connect the output to the HI-Z input with the TS jumper cable. With phantom power turned off adjust the gain control while looking at the VU meters in REW. Follow the instructions at that point. (since I haven't gotten that far into it yet)

Actual measuring: Leave the card input level the same or change to +4 pro level ?? Connect the mic via balanced connection to the soundcard. I will be turning phantom power on at some point since the mic needs a preamp. Connect the right channel? output from the card via the 1/4" to RCA adapter to my preamp. Follow the REW instructions.

Do I have it completely right, or am I still confused?

If I only had a standard soundcard this would be real simple. I apologize for the amount of detail I am requesting and thanks a million for your help!

Unbalanced operation is a function of the connector type used. A TS will automatically assign the interface to operating in unbalanced. So, if you have a cable with TS connectors on each end, the interface from Line-out to Line in will be unbalanced.

Yeah, the so-called HI-Z 1/4" input is a standard high input impedance Line Input interface. You'll connect a jumper cable (with TS connectors on each end) from one channel of the six Line-out (that you have also selected in REW) to one channel of the two Mic/Line-In (that you have also selected in REW). The Input Gain control will be used when setting the proper levels for Input during the soundcard calibration.

I believe the consumer or pro level is set up with respect to the Line Output. If the preamp you are using is a consumer level device, select and leave it set to consumer level...... The Input Level is set using the Input Gain Control. It has a very wide range.


Absolutely. Use XLR connector to the same Input you used for calibration loopback. A or B.

Well, if you use A channel for the mic, turn on the phantom power to the A channel.

Don't understand the question?

Yeah, either TS to RCA or TRS to XLR.

brucek

When doing the actual measuring I thought I connected "right channel out" from the soundcard to "right channel in" on the preamp since only one channel will be used for measuring. I assume this is "mono" and not a "summed" signal I am sending from the card to the preamp? IOW, I do not connect a Y-adapter to the soundcard output?

Some people connect a Y-adapter at their receiver "CD" or "AUX" input (I do), so that when it comes to taking a measurement with the Mains along with the subwoofer signal, they will be driving both Mains. The signal is indeed mono from the soundcard via REW, but you may want to split it at your receiver.

Normally, you take a sub only measurement, and setup your equalization. Then add the mains, and measure, so that you can assess the crossover region.

brucek

Bruce, I use 2 Rel Storm III subs that are directly connected to my amplifier left and right outputs via neutrik connection at the sub input. The crossover is controlled at the sub input. It's a completely different setup than using a Behringer, I think. From what I can understand, in my setup, I would just use a single cable coming out of the card and connect that single cable to the same channel at the preamp input.
My concern is just making the right connection between the card and the preamp. FWIW, I use all separates in my 2 channel system, no receiver.

Yep, OK. Then I take it you're not doing this frequency response measurement in anticipation of using a BFD equalizer for your subs. Perhaps, you want to find the best positioning for the subs?

Mmmm, I would think you would want to use the single cable from the soundcard (which is basically the listening position response), to feed both Left and Right of the preamp. Your measurements will be a combination of your mains and both subs in concert.

brucek

I just want to see where I am before I decide on a BFD.

That's exactly what I want to do, measure the response of both main speakers & both subs outputting signal at the same time. If this is the case I would connect the left and right outputs from the soundcard to the left and right inputs of my preamp, correct?
I thought I read in REW instructions to only connect to one channel and turn the other one off.

Well yeah, REW only accepts a single channel (left or right) as an input from a single microphone or meter. REW outputs a single mono signal on both left and right outputs of the soundcard though, irregardless which input has been selected as the active one.

Some people take a single channel output and split it to their receivers, so that when they add the mains, they get both of them on. Some people realize that the software actually outputs from both left and righjt channels of the soundcard and connect two cables to left and right of their receivers, but the outcome is the same....

brucek

Ah, ok, so I misunderstood. I will just connect both outputs to both inputs on the preamp and measure the response with both mains on.

This is taken from REW instructions:
To make measurements that will show the response of main speakers as well as the subwoofer, and to view the integration between subwoofer and main speakers, connect to an AV processor input so that the effects of your AV processor's bass management can be included in the measurements. Connecting to the left or right channel of an analog input will allow the corresponding main speaker and the subwoofer responses to be measured - turn off or disconnect the relevant main speaker or the sub to exclude them from a measurement.

I guess this is what confused me.

Yep, and there's no problem if you want to just use one main. Most people use two. Certainly the important thing is to be sure not to try and use any soundfields that use all the speakers. You want all soundfields off and set the preamp/receiver etc in stereo only...

brucek

Got it.