Guitarfilter: Direct Injection
March 3, 2011 8:58 AM   Subscribe

Guitarfilter: I am looking to find the best DI (Direct Injection) box for my needs. The most important things to me are: 1.) Active not Passive 2.) Has two outputs, one to USB for PC recording and one (as bypass or as wet) standard 1/4" to feed to amp 3.) Low latency.

This is for home studio recording. i am looking for the best combination of quality, simplicity, and functionality. Bells and whistles are nice, but first and foremost it needs to just work when plugged in and provide clear tones without static, hum, etc.

I don't mind spending the money for a great product, although I am no danger of being considered professional, so I probably don't need an $800+ unit.

What do you say?
posted by kjl291 to Media & Arts (13 answers total) 2 users marked this as a favorite
Response by poster: ADDITIONAL NOTE: I notice that many units are FireWire compatible - is this better/preferable to USB?
posted by kjl291 at 10:01 AM on March 3, 2011

You talk about a DI box, but if you want a USB and conventional outputs, you're probably really looking at a USB audio interface with a Hi-Z (instrument) input...

There are plenty of options - the M-Audio Fast Track ( ), for example, would do what you required, although it has RCA outputs rather than 1/4" so you'd need a converter cable to manage that, and perhaps a micro mixing desk if you wanted to output the sound from the soundcard through some monitors rather than just using the headphone socket on the front, or your amp...
posted by benzo8 at 12:01 PM on March 3, 2011

Response by poster: Yeah, I guess you are correct "DI" might not be the correct term...just looking for ideas for an audio interface that meets the description as above, to record guitar to the computer and also put the signal through the amp...
posted by kjl291 at 12:25 PM on March 3, 2011

Personally then, I would split the signal before the audio interface using something like the Morley ABY switch ( )... Then you'll have no latency questions at all, and you can continue to play your guitar into the amp when the computer is off without having to unplug and replug things.

At that point, you're just looking for a decent USB audio interface, and you can choose as to your budget. Again, the M-Audio range is a pretty decent place to start.

In terms of your other question, re: firewire vs. USB - USB 2.0 has plenty of bandwidth for two full-duplex stereo in/outs - firewire has even more bandwidth, but you probably won't need it unless you're thinking of using multiple channels of audio simultaneously.
posted by benzo8 at 1:02 PM on March 3, 2011 [1 favorite]

Response by poster: Great information - very much appreciated! Perhaps I can ask you a few more questions? Do you have an opinion about active vs. passive?

What spurred this question is that I have been using a Line 6 GX, which a simple and inexpensive passive unit, and it does it's job pretty well for the market at which it is aimed. The main reasons for me to pursue something different are:

1.) I wanted something just a bit more professional (and I will state it again, I am in no danger of being confused with a professional).

2.) The signal was not too bad but there are some minor issues with static and pops.

3.) Listening to the signal of the headphone jack present the latency issues. I was able to tweak settings to get the latency pretty darn low (in the 20-30ms range) but it is still slightly there, and even that slight amount can throw you (or me at least) off when playing.

And I do like the idea of splitting the signal beforehand...
posted by kjl291 at 1:21 PM on March 3, 2011

Response by poster: And also I had considered something like the Mackie 402-VLZ3 Premium 4-Channel Ultra-Compact Mixer.

Any thoughts?

I realize it is not USB...but it sounds like it could be a great solution, too. The question is, if the output goes into the sound card (is that correct?) then won't the quality of the soundcard be the determining factor.
posted by kjl291 at 1:39 PM on March 3, 2011

Response by poster: And are there any latency differences with recording via USB, FireWire, or Sound Card?
posted by kjl291 at 1:53 PM on March 3, 2011

Best answer: Firstly, I don't think you need to worry about active DI boxes here - there's no requirement for any preamplification if you're plugging your guitar directly into a Hi-Z / instrument input...

If you're getting pops and static, there's a chance that your ASIO settings are incorrect, but as you've been playing with them in order to reduce your latency, I'm going to assume that you know what you're doing on that score.

Virtual guitar amps, whilst they're improving all the time, do tend to be noisier for high-gain sounds than the equivalent amplifier - some static and noise can be unavoidable, though it often can be ameliorated by reducing the input level on the plugin.

A quick way to test if the soundcard is introducing noise (rather than, for instance, the guitar itself) is be unplugging the guitar cable - if you're still getting static/hum with your chosen plugin settings, it's likely that you will be able to improve matters by purchasing a better quality card.

Monitoring latency is another issue. This is unavoidable to a degree - if you want to monitor the sound of the virtual amp, then you need to allow the signal to traverse the ASIO buffers and be effected by the amp before you can hear it. I tend to find that anything above 15ms starts to affect playing. If you can't reduce that any further on your setting then you have two options - monitor the input, rather than the output, or record an already effected sound (ie: record your amplifier and eschew the virtual plug-in).

Latency is directly related to CPU power - the faster your machine can handle the data in the ASIO buffers, the small they can be, and thus the lower the latency. Better, more efficient drivers can also help. The Line 6 drivers are not particularly good as I recall. You might want to try ASIO4ALL and see if you can get any better latency there.

The Line 6 drivers do have a "zero-latency monitoring" option, but what you then hear is not effected by POD Farm, so it may not be your solution.

The mixer you linked is another way of splitting the signal before you enter the sound card, but as your correctly surmise, what is recorded in the computer is still subject to the quality of the card. The mixer itself might introduce some noise too, which means it might end up being a detriment rather than a help...

In terms of USB/Firewire/Soundcard - a USB or Firewire soundcard introduces a small further amount of latency (the fw/usb round-trip) but it's pretty negligible. Your GX is a usb sound card.

If your PC is reasonably modern, I think you'll solve most of your problems with a better quality sound card. With my Focusrite Saffire, I get about 6ms latency, which is plenty quick enough to play live through POD Farm or Amplitube, and that's pretty much down to the drivers. I still get some noise using the Hi-Z input, but a) my guitars aren't silent, and b) as I mentioned before, virtual amps tend to overdo the input gain a bit...

If that's not the path you want to follow then splitting the signal before the sound card, monitoring your playing on your amplifier and then re-amping the recorded guitar signal afterwards (where latency isn't an issue) will be the best way forward.

I'm sorry if this is kind of rambling - they questions you're asking cover a lot of ground!
posted by benzo8 at 2:12 PM on March 3, 2011

Response by poster: You are not rambling at all, and the information you are providing is invaluable to me - I've already learned a lot.

The point you make about these units actually being sound cards in and of themselves is a great one - I hadn't thought of it that way.

Is this the unit to which you refer: Focusrite Saffire Pro 24 Firewire Audio Interface? It connects via firewire, and you can jack your guitar straight into it and record?
posted by kjl291 at 2:26 PM on March 3, 2011

Well, mine is the Focusrite Liquid Saffire 56 but yes, the drivers are identical and the 24 is a very good interface. The Hi-Z input is quiet and the microphone pre-amps mean that at a later date you could buy a reasonable microphone (for instance, a Shure SM57), and record the sound directly from your amplifier...

So, assuming you have a firewire interface on your computer, you would connect the Focusrite, install their drivers, set your ASIO buffers until you have the lowest latency possible without pops and crackles and off you go.

One caveat: if you're using POD Farm, it probably uses the GX as a authorisation dongle, which means you'd need to have it connected to your computer to run the software, even though you're not using it as an interface any more, but have farmed those duties to the Focusrite. (I have to do the same with my POD XT - it's the biggest dongle in the world!)
posted by benzo8 at 2:49 PM on March 3, 2011

Response by poster: Ha! Although I don't know about the "biggest" dongle - try a Spider IV with an FBV Shortboard attached to your USB port.

Anyway, again, I sincerely appreciate the info!
posted by kjl291 at 3:00 PM on March 3, 2011

I second the Saffire Pro 24 - I've been using one for about a year and I love it to bits. It's a little larger than other boxes roughly in its price range, but the IO ports and routing options more than make up for it - the MIDI ports are great for plugging in MIDI floor pedals to control the virtual effect stacks, for example. The AD converters are a huge step up from the likes of the M-Audio Fast Track, and the latency is much better.
posted by vanar sena at 5:22 AM on March 4, 2011

Radial Engineering JDI or JDV! They are the best; unbreakable, clean, intuitive, designed around possible roadblocks.
posted by alexandermatheson at 11:07 PM on March 30, 2011

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