# Audio Interfaces



## Ultimateherts (Nov 13, 2006)

I think we need to talk about audio interfaces. A lot of the pro audio interfaces I believe are more geared towards the carpc crowd for a couple of reasons:

1) The Dac in them are far superior than onboard sound can offer. 

2) They come in an assortment of flavors ranging from firewire, usb, pcmcia/express card if you have a laptop. USB and Firewire are great because the cable lengths allow them to be hidden for clean install purposes.

3) They offer numerous outputs ranging from (4) RCA out, SPDIF, and TOSLINK.

A good cost effective example being the Focusrite Saffire 6. Focusrite is known in the pro audio recording world for providing good products given the price.

Focusrite Saffire 6

USB interface bus powered

(4) RCA outputs

(2) Balanced outputs

Saffire 6 USB | Focusrite


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## t3sn4f2 (Jan 3, 2007)

Be careful with those USB powered DACs. Pretty much all lack the standard 2 volt output. The one you linked has it BUT it is only on the balanced output. Which means that the device it connects to would have to be compatible (ie bal/diffbal). The unbalanced RCA side only have .5 volts out, that half the typical rating you'd normally see from even the simplest basic USB DAC.

If you are interested in an affordable driverless USB DAC with only 2 channels out, 2 volt out, and validated excellent measured and blind performance. Look into Nwavguy's ODAC. Only $100 IIRC.

nwavguy.blogspot.com/2012/04/odac-released.html


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## Ultimateherts (Nov 13, 2006)

I am aware of his product, however then it is not as cost effective because most would need (2) of them for (4) channel output. 
I have the Focusrite Saffire 6 (just came today) and I will see how it fairs.


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## Candisa (Sep 15, 2007)

We are dreaming of having a bigger house with room for an own recording studio one day...
One time we almost got that chance (unfortunately went all wrong) and started looking out for some gear already...

We were planning (and it seams not much has changed since then) to run an M-Audio ProFire2626 interface...
The reasons why are very similar to the arguments to select a good interface for a carPC:
- good quality DAC's
- already 8 inputs and outputs on it
- expandable with dual ADAT-inputs and outputs

Combine this thing with 1 or 2 Behringer ADA8000's and you can run up to 24 analog outputs for a MASSIVE install full-active...

Think about this: 
- 5-ways frontset (midbass, low-mid, high-mid, tweeter, supertweeter) = 10ch
- 3-ways rearset (midbass, mid, tweeter) for passengers, 5.1 sound or ambient stereo = 6ch
- 2-ways substage = 2ch
- shakers = 1ch
- 5-ways center = 5ch
TOTAL: 24ch

Find the right car to built this and you can spend your hobby-budget and -time on 1 install for the next 10 years or so :laugh:

Isabelle


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## Ultimateherts (Nov 13, 2006)

For Behringer I would buy this model and mod it:

Behringer


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## oca123 (Aug 16, 2010)

The problem is that pro audio sound cards typically come with as many inputs as they have outputs. USB2.0 was not designed to handle this, so you are already pushing it to its limits. There are also power requirements. You will probably need auxiliary power to use a USB card to its full potential. This is where it gets tricky... you can't just hook up 12V from your battery. You need a quality *regulated* power supply to provide a steady voltage, and absorb the peaks and dips.

I have gone through two M-Audio Fast Track (the 1U rackable USB 8x8 ones) and in both of them, the chip that the USB is hooked up to directly after arriving to the sound interface overheated and melted.

I had good luck with an Edirol FA-101. Behringer is also working on the FCA610 which, when it comes out, would fit the bill OK.

I spent quite a bit of time experimenting with DRC, Carputers, and the like. Eventually, I got to the point where I started thinking about hiring a designer to build a custom 8 channel DAC with 8v preouts based on one of the ESS chips. This is when I decided to stop the insanity and use a regular processor.


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## Ultimateherts (Nov 13, 2006)

oca123 said:


> The problem is that pro audio sound cards typically come with as many inputs as they have outputs. USB2.0 was not designed to handle this, so you are already pushing it to its limits. There are also power requirements. You will probably need auxiliary power to use a USB card to its full potential. This is where it gets tricky... you can't just hook up 12V from your battery. You need a quality *regulated* power supply to provide a steady voltage, and absorb the peaks and dips.
> 
> I have gone through two M-Audio Fast Track (the 1U rackable USB 8x8 ones) and in both of them, the chip that the USB is hooked up to directly after arriving to the sound interface overheated and melted.
> 
> ...


Well there are quality ones made by Carnetix:

CarNetix P2140

CarNetix CNX-P1900


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## 14642 (May 19, 2008)

I have the Edirol USB-101 and it's been GREAT. I started with a super expensive TC Electronics POS and it was a disaster. The Edirol runs on a wall wart that outputs DC, so providing the right voltage is pretty easy--you can get a lighter adapter at Radio Shack that has a selectable output voltage--or you can build one yourself with a pair of NPN transistors, a little heat sink and a zener diode. The secondary output of the carnetix PS can drive it. I have a bunch of USB stuff in my car, so I use the secondary output to switch a relay that provides power to the interface and 2 powered USB hubs. 

The Edirol sounds fine and the balanced outputs can be connected directly to the RCA inputs of most modern car amps. I send audio via toslink to the interface and then process the 8 channels in AudioMulch over USB in a Mac mini running Windows XP. Works great. Super reliable (for a car PC). Sounds great and there's NO noise.

Get the Carnetix 2140.


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## oca123 (Aug 16, 2010)

^^ Agreed. I had a very similar setup, but with the FA-101 which is the Firewire version of that card. The USB version caused higher CPU usage than I could deal with. At the time, I was processing 8 channels using convolver VST and long FIR filters, 16 partitions, so CPU usage was already high.
The Edirol interfaces are great. They are bulky though. I thinik there is a company here locally t hat makes sound cards that would fit the bill, they are internal cards for studio sound, but I can't remember their name... fairly expensive though.

I also tried the Asus Sonar. It didn't work out, there were issues with teh drivers, and there was some noise because the card is internal.

In regards to running Optical into the Edirol... that's what I did. I ran my iPod through an i-20 dock, which gave me an optical link, which I fed into the Edirol, which then sent it through Audiomulch, etc.

I made the mistake early on of mounting the sound card in a very hard to reach place. When came the time to run sweeps, etc. to generate the filters using the DRC package I was using, I raelized that I had to
1) turn on phantom power using a switch in the back of the card
2) I don't recall exactly, but if I remember correctly, I was not able to have both Optical in AND Microphone in, at the same time... At the very least, I remember that there was a button that I had to push on the card, and sometimes Audiomulch would see no input and pushing that button would fix it. It had to do with clocking of /synchronizing with the optical signal, and the button was "Digital In" in the front of the card. It took me an entire day to take everythring out and mount the interface somewhere I could access it easily.

I am considering going back to a carputer, since I just sold my Arc PS8, and haven't made up my mind on what to use next.
I saw a USB volume knob on Amazon once. I think it could be set up to cause MIDI events? That was my big issue - volume control. If the USB volume knob works, I guess its MIDI port could be linked to the gain setting of a VST plugin after the convolver, but right before the output, in audiomulch?

I guess a more elegant solution would be an 8 channel line driver with a master volume knob.

I believe the Maudio 2626 also has a master volume knob, which could be relocated. The Edirol has no such thing.


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## Ultimateherts (Nov 13, 2006)

oca123 said:


> ^^ Agreed. I had a very similar setup, but with the FA-101 which is the Firewire version of that card. The USB version caused higher CPU usage than I could deal with. At the time, I was processing 8 channels using convolver VST and long FIR filters, 16 partitions, so CPU usage was already high.
> The Edirol interfaces are great. They are bulky though. I thinik there is a company here locally t hat makes sound cards that would fit the bill, they are internal cards for studio sound, but I can't remember their name... fairly expensive though.
> 
> I also tried the Asus Sonar. It didn't work out, there were issues with teh drivers, and there was some noise because the card is internal.
> ...


Just curious why you need (8) channels? Subwoofer really only needs a basic EQ setting and then if 2way (which I will be running) you would only need (4) cahnnels + (1) for the sub.


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## oca123 (Aug 16, 2010)

Oh, I used the carputer as a sound processor.
So stereo goes into one of the inputs (I like using optical) then the computer splits up the signal, fixes frequency response AND impulse response (to some degree) and outputs tweeters (2 ch) + mids (2 ch) + midbass (2ch) + center (1ch) + subs (1 ch)

I'm excited to be running a system with no tweeters now, because that means I'll be able to run sides which should be interesting.... so t hen it will be
Widebanders (2ch)
Midbass (2ch)
Center (1ch)
Sub(1 ch)
Sides (2ch)
= 8 channels.

I guess I could run the sub off a separate cheap 2 channel USB interface, and add some rears as well... but that would mean I really have nothing else to do


EDIT: This was because at the time there wasn't anything to do this kind of processing. The MS8 was a tease, wanted to do my own


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## Ultimateherts (Nov 13, 2006)

oca123 said:


> Oh, I used the carputer as a sound processor.
> So stereo goes into one of the inputs (I like using optical) then the computer splits up the signal, fixes frequency response AND impulse response (to some degree) and outputs tweeters (2 ch) + mids (2 ch) + midbass (2ch) + center (1ch) + subs (1 ch)
> 
> I'm excited to be running a system with no tweeters now, because that means I'll be able to run sides which should be interesting.... so t hen it will be
> ...


I guess I follow the KISS rule. I would imagine how much harder that would be to tune! I can barely get 2way + sub to image correctly. Gotta love reflections in an SUV!


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## oca123 (Aug 16, 2010)

I didn't know anyone on DIYMA followed that rule, hahaha. When you see how far some of us take things... it's mindboggling.
I have to say, the setup sounded amazing. I don't think I've come close to this again in this car. This thread and just circumstances have made me want to try it again, especially now that my setup, speaker locations, etc. have changed. I should be able to pick up more direct sound with my microphone, which should result in more effective time domain corrections... but this is off topic.
I find it easy to tune with that setup, because you can take something like REW and run measurements, pick a target response, and it will generate EQ settings for you. There's are also commercial packages that can generate FIR filters based on measurements.

To get back on topic.... I have spent many hours researching audio interfaces for a car PC. If you're going to use a separate processor, optical is fully digital and newer processors will take toslink inputs, so quality of the audio interface is not too important.
If you want to take things a step further and do the processing on the computer, a medium to high quality sound interface will be required.
High quality sound interfaces run thousands of dollars, and will yield little improvement over mid-end offerings in a car, at least in comparison to plethora of things you can do to improve your setup (deadening, enclosures, speaker locations, tuning, etc.)
mid-end offerings are home studio interfaces, like m-audio stuff, the edirol line, saffire, etc.

There's also MOTUS interfaces, which seem worth looking into.

The 1010LT by M-Audio is also OK, if you have a PCI slot on your motherboard.


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## Ultimateherts (Nov 13, 2006)

I don't know as I like to keep everything down in cost -vs- performance. RME makes some great products, but the prices are not cost effective enough for me to buy one. Steinberg is another that is very good as I own one of their audio interfaces for my up incoming studio.


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