M-Audio Basic Setup Question

**rolyasm** · **07-15-06, 04:45 PM**

Hello,
Just reading through the setup manual and it states not to use microphone inputs. I will post a link or a picture of the back of my soundcard. Anyway, want to make sure I am doing this right. So I use the 1/8" stereo out on MAudio connected to Reciever. Then from my SPL to soundcard I use the 1/4" balanced line in since I don't want to use the stereo mic input? So as per the diagram I don't want to use the 3.5mm line in, but rather the 1/4" balanced in?
Also, thinking about he Midi interface. Do people tend to find a better filter set using the interface, or is it just as effective, or more so, inputing by hand? Is the basic difference just speed of inputing data, and how much time does it actually save?

Last Question. I do have a processor ready, but since all I am doing currently is hooking up my subs and tweaking them (don't have mains or surrounds yet), am I reading correcty that I don't even need my processor. Instead of the processor, I am hooking up my soundcard directly to the BFD and running test tones that way?
Thanks.
Roly

**brucek** · **07-15-06, 05:56 PM**

Quote:

Then from my SPL to soundcard I use the 1/4" balanced line in since I don't want to use the stereo mic input?

The feature sheet on your M Audio Mobile interface shows the 1/4" TRS balanced line input as capable of auto-sensing unbalanced (although the manual on-line didn't reference anything but balanced). If that's the case you should be fine using a 1/4" Mono TS connector on this input (just like you would with the BFD) and hook the RS SPL meter up in an unbalanced configuration using the TIP and SLEEVE only.

Quote:

I do have a processor ready, but since all I am doing currently is hooking up my subs and tweaking them (don't have mains or surrounds yet), am I reading correcty that I don't even need my processor. Instead of the processor, I am hooking up my soundcard directly to the BFD and running test tones that way?

Well yeah, but I really think the only way to go is with the processor so you can use the crossover that you'll ultimately be using anyway. Just because you don't have mains is a plus and the way you are supposed to do your measurements with the sub only....

brucek

**rolyasm** · **07-15-06, 06:21 PM**

Quote:

hook the RS SPL meter up in an unbalanced configuration using the TIP and SLEEVE only.

By tip and sleeve do you mean just inserting the tip and nothing else? Sorry, not sure what you mean. The 1/4" looks like all it is a tip and sleeve.

Roly

**brucek** · **07-15-06, 06:46 PM**

Quote:

Sorry, not sure what you mean

The Balanced line input of the M-Audio device would normally expect a 1/4" TRS (Tip, Ring, Sleeve) connector as shown below in the top connector of the picture attached. The end or tip (3) is the positive phase of the balanced connection, the middle or ring (2) is the negative phase of the balanced connection and the sleeve (1) is the ground.

You don't have a balanced output from your SPL meter. It has an RCA type unbalanced output. To connect this to an input on your soundcard module that expects a balanced TRS connector, you have to use a TS connector (tip, sleeve) as shown in the picture on the bottom. The tip (3) is positive and the sleeve (1) is ground. The soundcard recognizes that the sleeve and ring is shorted when you plug in the TS connector and it adapts to be a unbalanced circuit. This is the same as the balanced inputs on a BFD act.....

brucek

**rolyasm** · **07-15-06, 08:15 PM**

Thanks Brucek,
You are a busy man. I am building a sub on the HTGuide forum. One of the posters had this to say concerning the use of the mic plug and using the mic vs. 1/4":

Quote:

That advice is assuming you will be using an external mic preamp and feeding a line-level signal from the preamp to the sound card. The MobilePre has the preamp built in so you should use the mic input and turn on phantom power to the mic. I assume you are using a pro mic like the Behringer ECM8000 with an XLR plug.

I had posted this question about the same time on that forum and received, obviously, different answers. Does the fact that my MobilePre has a preamp built in change anything? Ad I am using the ecm-8000 mic with XLR. I really apprciate all the help.
Roly

**brucek** · **07-15-06, 08:31 PM**

Quote:

I am using the ecm-8000 mic with XLR.

Ah, something that you failed to mention and I assumed a RS SPL meter - hehehehe. It makes a big difference though.

I'm not as familiar with the ECM8000 as Sonnie is (he might also come in and help out here). But my understanding is that it has a pre-amp with phantom power to run it, and so if the M Audio Mobile has its own pre amp with a phantom power mode (which it appears it does) then the quoted answer you received from the other site is quite correct. Simply plug the mic into the XLR mic input.

Be sure to match the same channel on the 1/8" stereo line out connector. I assume it has a left and right that match the two balanced mic inputs on the rear of the unit... REW expects that the same input and output channel is used (i.e. left or right)

brucek

**Sonnie** · **07-15-06, 09:34 PM**

This is correct info on the ECM8k... it needs phantom power supply.

Hey Roly... you can build your sub here too... we are a forum centered around subs so ti would be nice to see it here. Thanks!

**rolyasm** · **07-16-06, 01:19 AM**

Thanks Sonnie,
I really am dumb on just about every audio subject know to man. I have been trying to learn and have read some books, but it is a long, slow, painful process. I would be happy to post the sub on the forum, but it isn't a stand alone sub. I have put 4 15" avalanche drivers in the front of my riser. Not an IB, but a big sub. If you want me to post it, let me know where and I will post some pics or something.
Roly

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