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There was a discussion a while ago about external interfaces for use with DP's. The Behringer UCA202 came out well because of the price situation, but I am looking for one with balanced ins/outs. I'm considering a few models and I wonder if I could get a few opinions about them. Criteria are software-piano-centric:

1. Good DAC (probably all these are fine, though)
2. Good headphone amp (this matters a lot to me--two would be nice in fact)
3. Low latency
4. Balanced ins/outs (at least two each, so we can do stereo)
5. Midi in is nice, but optional

The quality of the analog-to-digital is less important (for me, anyway).

So here are the models under consideration:

• Presonus AudioBox USB
• Focusrite Scarlett 2i2 USB
• Focusrite Saphire 6 USB
• M-Audio Fast Track Pro USB
• Mackie Onyx Blackjack USB

Also considering the possibility of the Focusrite Scarlett 8i6, but it costs more and I'm not sure what advantage it has. I'm not considering the tascam 122 or 144 because they don't have balanced ins/outs.

MacMacMac, I believe, was saying he's not much impressed with the headphone amp on the Presonus, though I had heard good things elsewhere. Any thoughts about any of these models?

Just from a cursory check of the specs, it seems like the Focusrite 2i2 is a likely candidate. But it seems like the M-Audio and Presonus are more common. I guess the M-Audio kind of appeals because it has more outputs. Maybe later I will get a headphone amp and be happy to have an unused RCA line-out.

Did I miss any interfaces?

gvfarns,

I don't have any personal experience with any of the interfaces you listed. I have a Edirol (Roland) UA1000 that I like very much. It's a fairly old device, but you might find one used on eBay for a good price. I've heard the much newer UA101 is a nice machine too. Both have balanced ins and outs.

Thanks for the suggestion. Having a hard time tracking down a live Edirol product. The UA-25 seems like it would be nice, but availability...not so much. I'll keep looking.

No other opinions? If not I'll probably pick up the Scarlett 2i2. I wish it had more outs so I could easily hook up a headphone amp in addition to my monitors somewhere down the line, but there's no point in getting greedy, especially to accommodate hardware that I likely won't get for a long time, if ever.

The one with really hot and cold reviews out there seems to be the Mackie.

Do any of these guys not have drivers that allow you do operate software pianos with very low latency?

[quote=gvfarns]There was a discussion a while ago about external interfaces for use with DP's. The Behringer UCA202 came out well because of the price situation, but I am looking for one with balanced ins/outs. I'm considering a few models and I wonder if I could get a few opinions about them. Criteria are software-piano-centric:

1. Good DAC (probably all these are fine, though)
2. Good headphone amp (this matters a lot to me--two would be nice in fact)
3. Low latency
4. Balanced ins/outs (at least two each, so we can do stereo)
5. Midi in is nice, but optional

The quality of the analog-to-digital is less important (for me, anyway).

So here are the models under consideration:

• Presonus AudioBox USB
• Focusrite Scarlett 2i2 USB
• Focusrite Saphire 6 USB
• M-Audio Fast Track Pro USB
• Mackie Onyx Blackjack USB

Hard to go bad with any of these. I have a Firewire version of the Presonus. It's headphone amp will drive my AGK K240 uncomfortably loud with the knob not even at the half way point.

mAudio does not have a good record of releasing new OS device drivers. You might check each web site to see the dates on their drivers

Best if you don't need drivers. That is one big reason I have what I do. It is just "plug and go" on the Mac with no software to install. OK, that only saved me 5 minutes once but the OS has now been upgraded twice and I did not have to wait for Presonus to write a driver.

You are looking for "low latency". That one is easy as latency is not a function of the interface box. It is an OS and device driver thing.

SOme things might matter to you or not. For example I could not use any box with knobs or jacks on the top, all controls and the headphone jack had to face forward -- I'musing a sort of rack mount type setup. So think about little things like how you will reach for the volume control on the headphones or monitor.

My E-MU 0404USB interface has a headphone output (single) that sounds very solid to me. Much better than the headphone jack on, say, my home theater receiver or by far better than the ones on laptops and computers. I think that is in large part because the 0404USB runs on AC mains power rather than USB bus power (one of the few cheap interfaces that do so and a "main" reason I chose it.

All of its other specs check out with your list pretty well, too. Unfortunately they recently stopped making that exact model although you can still find them at various online stores and dealers.

Yeah I have seen the 0404USB in many old threads but it's not easy to find now. Bummer.

So I guess in this forum we don't have people who feel that the difference in quality between headphone amplifiers (with the same power) is large.

Somewhere I read that the output impedance of the headphone amp should preferrably be at most 1/8 the impedance of the headphone itself. My Behringer apparently has an output impedance of 50 ohms and my headphones are 50 ohms as well. 1 to 1...not good. The Scarlett has output impedance of less than 10 ohms. Actually I don't know what output impedance actually is or how, in particular, it affects sound quality. That's what I read, though, and only the Focusrite stuff seems to be saying what their output impedance is.

From what I've read (I feel that I actually know less after this forray ) the issue of damping factor (ratio of driver to output impedance) is much more complex for headphones than speakers. 1:1 or even higher may be perfectly fine, it really depends on what the designers of the particular headphones were targeting (and good luck finding that). I suspect it doesn't matter as much as one might think it would, but I haven't done any testing along these lines.

Here is the post I referred to, talking about output impedance. Maybe you can make more sense of it than I can.

Nice article, thanks! Personally, I'd go with the lowest drive impedance to minimize frequency response / complex driver impedance interaction. A bit of output impedance (the "1/8th Rule" in the article) isn't a huge issue, and may actually make the output driver more stable (driving complex impedances can lower gain and phase margins of systems that employ negative feedback to linearize the frequency response and lower the output impedance, such as op-amps). For instance, it's not uncommon to see a series resistor in op-amp circuits that directly drive long lines.

Holy cow. There is a lot of jargon in that paragraph.

I went ahead and got the 2i2, which has (at most) 10 ohms. With my HD595 that would be a ratio of 1/5. Not optimal, I guess, but better than my current 1/1. We'll see if I can actually detect a difference when it arrives. This does seem to fly in the face of the "just get an amp strong enough to cause sufficient volume in your cans" wisdom. Whether there will be a practical difference we have yet to see.

I tried finding the output impedance on the other interfaces but came up empty. Since I can't find specs on the other models, I had to assume they were worse (I'm cynical like that). Plus the 2i2 just looks so coooooool.

Thanks for your help, guys.

Ok, the Focusrite Scarlett 2i2 showed up today. I hooked it all up and gave it a shot. It works well except for two things, one of which is probably a deal killer:

1. The lowest latency I can achieve with Galaxy using this interface is 23 ms. And that's pushing the envelope. With my old Behringer UFO202 I was getting 8.3 ms without crackles. I can sense any latency over about 10 ms, so I can't deal with this. I tried changing the bit rate to 96k instead of 44.1k. Still 23 ms is the lowest non-crackle latency. Is there a better driver or something I should be using? I'm using the latest one on focusrite's web site.

2. The headphone amp sounds good, but it clearly cannot handle a high impedance headphone. Mine are HD 595's with 50 ohms of impedance and I have to turn it almost all the way up for my normal listening volume. At the moment this is the highest impedance headphone I have but I had considered one with a higher impedance in the future. The Behringer could clearly drive a headphone with far greater impedance than my 595's. Further, since there are only 2 outs with this interface, adding a headphone amp later will not be trivial.

Unless I can figure out a solution to problem #1 I'm returning this thing for sure. I just worry that other interfaces will have the same problem. Does anyone use the M-Audio FastTrack Pro USB?

So far, Behringer > Focusrite, much to my chagrin. Too bad it doesn't do balanced in/out.

Maybe you said and I missed it but are you using an ASIO driver? If you're using the built-in Windows drivers the latency is going to be awful with 'most any hardware. Or at least it has been on the three different laptops I've tried it on (caveat I'm using Garritan Basic and not Galaxy).

Very few cheap and/or bus-powered audio interfaces will do a decent job of driving high-impedance headphones. Sounds like you got lucky that the Behringer/HD595 combo yields a pleasing sound. I doubt it has all that great a voltage capability (important for high-impedance 'phones) or even current capacity for that matter. Is the Behringer bus-powered or does it have its own power supply?

Yup ASIO, apparently. Within Galaxy I select "ASIO" as the driver type, and then I select the scarlett 2i2 driver, which I assume is ASIO since it shows up under that menu.

When I get home I'll install ASIO4ALL and try it out. I don't know if that works with this interface, but if it does, it will be my last ditch effort.

With the Behringer both the Behringer driver and ASIO4ALL work, but the Behringer driver had lower latency by just a bit.

The Behringer is bus powered, as is the Focusrite. I never tried actual high impedance cans with it, so I can't really say. But I know the volume dial went way higher than what I was using, unlike the Focusrite. To be clear, the headphones sound great using either the Behringer or Focusrite. I think it would have to be a pretty bad amp for these cans to sound bad.

If I return this I'll likely pick up the M-Audio. It has more outs, so I can take 2 and hook them to an external headphone amp if I ever find myself the owner of some high impedance cans.

Brent_H, are you just using onboard audio? I kind of wish this forum had polls. I'd like to know what interface everyone is using. I was very surprised that the higher end Focusrite appears to be lower performance than the uber-budget Behringer.

I have the keyboard usually situated just out of reach of the cable to my E-MU interface. So I often plug in right there and just use ASIO4ALL with some cheap (freebie) headphones plugged in to the laptop's headphone jack. Sounds like poo but the latency is low ;-)

If I'm going to be at it for a while or if I'm going to record a project I'll schlep the keyboard over to the other laptop that sits plugged into the E-MU, running the Creative ASIO drivers which of course also have good latency. I plug my HD650 into the headphone jack of the E-MU and the resulting sound is glorious.

But usually I'm lazy and settle for bad sound to avoid moving the keyboard. Go figure.

P.S. I have ASIO4ALL, the E-MU 0404 ASIO drivers and Reaper all installed on both laptops so I can mix-n-match.

===== THE EXCITING CONCLUSION ============

OK, just wanted to let you guys know that it all worked out. The Scarlett 2i2 is a good interface.

The problem is that the Scarlett ASIO driver sucks. You have to install the Scarlett driver so the interface is recognized, then you install ASIO4ALL and set Galaxy up to use it. The resulting latency is 4.3 ms (compared with 11 under ASIO4ALL with the Behringer and 8.3 using the native Behringer drivers). And I'm using 24/96 now instead of 16/44.1. Excellent again. Bottom line, latency timings:

Focusrite (ASIO4ALL): 4.3 ms
Behringer (native ASIO): 8.3 ms
Behringer (ASIO4ALL): 11 ms
Focusrite (native ASIO): 23 ms

Also about the headphone thing, that was user error. Recall that the Behringer interface doesn't have an overall volume knob, so I had turned the volume way down in the software so my monitors didn't blow my head off. Setting it so zero, I have to turn the focusrite volume knob way down to like 1/4. Plenty of power there. And the headphones sound great. I can't really tell if they are better than they sounded under the Behringer (because of the output impedance thing...I'll get back to you on that when I've had more time).

After figuring this stuff out, the Focusrite dominates the Behringer in every way. Good interface...recommended.

Yeah, I made a similar mistake a few weeks ago. Cranked the "monitor" level knob all the way up on my E-MU 0404, driving my powered monitors. Actually I think it just got nudged up when I was rearranging equipment.

Anyway I was convinced that my monitors, which are a bit dodgy anyway, had pooped out me. Just awful, distorted, unmusical sound. Eventually I put that level knob back to midrange and everything sounded great again.

Congrats. I figured it was a driver SNAFU (i.e. the software not the human "driver" of the system). The drivers that get shipped with stuff nowadays are purely abysmal.

That sounds strange. ASIO4All is the software of last resort, meant to work with any sound card.

The vendor-provided ASIO module is meant to work better, and that was the case for me when I got the Presonus box ...

ASIO4All worked no better with the Presonus card than with the built-in sound card ... high latency. But the Presonus ASIO software gives just 3 msec latency.

So why can't Focusrite build a well-behaved ASIO for their own card??? (When you saw the high latency, are you sure you were engaging the Focusrite ASIO, and not just running raw?)

Yeah, same for me and the Behringer.



In the Kontakt configuration page, I selected driver as "ASIO" and device as "Focusrite USB 2.0 ...". In turning to ASIO4ALL I just change the device from focusrite to asio4all. I assume that means it was doing the ASIO thing with the focusrite driver as well. That's the way it worked with the Behringer driver. I think their native driver just sucks. I sent an email to that effect to the focusrite people. Since this is a relatively new product, they may actually still be thinking about it.

Actually I'm not sure you can improve much on the ASIO4ALL situation. The 4.3 ms is divided into 4 ms processing and .3 ms output. It's the output latency that has to do with the driver/device. So even if there is a way to fix the focusrite driver, we're talking about a maximum of .3 ms improvement. If for some reason I really wanted to get latency down (not that I can tell the difference between 4.3 ms and 8.3) I would have to get a faster computer.

A certain amount of latency is required. You don't want zero. The software computers the sound is little batches and then places the data in a buffer and then the driver clocks the data out of the buffer at exactly the 44.1K speed (or whatever is the speed you are using)

Between batches of computing samples the computer has other things to do, update the display and then maybe you are running multiple software instruments or recording audio or whatever?

Remember a millisecond of delay is the same as we experience in rel life when the source of a sound is one feet from your ear. When you are talking to someone you don't notice any delay when the other person moves from four to eight feet distance. Few people will notice a 20 foot speed of sound delay. But at 50 it is noticable.

Point is just don't worry about those tiny single digit milliseconds