Boss BD2 >interface>Computer?

[cton58]

Presonus AudioBox ITwo >Macbook.

Can I simply just run my Boss BD2 pedal via 1/4” input into my interface safely?

Thanks.

[Hugh Robjohns]

Yes it can.

[ef37a]

Safe indeed but there is always a slight problem when feeding an electric guitar into an AI and listening to the result on full range speakers and, probably worse, headphones...in a word "fizz"! The conventional guitar speaker has a response that among other graphical gymnastics, begins to fall at around 5kHz and is usually some 10-15dB down at 10kHz on the mid band response. This "top chop" removes a good deal of the fizzy, unpleasant harmonics from the guitar's signal. The use of an overdrive pedal before the interface is likely to make matters even worse although the tone controls on the Boss should help.

What is needed is some "speaker emulation" software and I am sure Wonks and others will have a zillion suggestions for plug ins, many free ones.

Dave.

[Wonks]

I assumed the OP was already going to use some amp emulation software.

There are two options when recording a guitar (I’m assuming it's a guitar rather than a keyboard you want to dirty the output sound of) like this. You can either use the instrument input mode or use a line input in standard mode.

The instrument mode is what you’d use when plugging a guitar in directly as it will provide a 1 megohm input impedance, the same as a guitar amp provides, which won’t ‘load’ passive guitar or bass pickups. The instrument mode normally makes the input a bit more sensitive, as guitar signals are lower than the nominal line input signal level.

The standard line input impedance for your interface is 10k, which if used directly, will make the guitar sound muddy, as if it has the tone control rolled almost fully back.

But with a pedal between the interface and the amp, the guitar ‘sees’ the input impedance of the pedal, not the interface, so it will run into the 500k impedance the Boss Blues Driver pedal presents (whether the pedal is on or off as it is buffered, unlike a ‘true bypass’ type of pedal).

Which gets me to the real point I need to make. Whilst you can use the BD-2 to significantly raise the signal level going into an amp to push the preamp harder (as well as just using the pedal’s overdrive sound), you can’t do that with the interface.

Keep the level so that the input level led on the interface stays green, and doesn’t go red at all. So start off with the level control on the BD-2 right down. The metering in your DAW tells you more detail, but try and keep the peak signal levels below -6dBFS (or a bit less).

Once the input level led goes red you’re at -0.5dBFS or more, and you will be getting nasty digital clipping (which is nothing like analogue clipping). You can’t use a high pedal level to drive the interface input the same way you would with an amp. So keep the output level down.

You’ll have more headroom to play with, with the input in line mode than instrument mode, so you might find it easier to not overload the input by using line mode.

If you are using the Studio One bundle that came with the interface as your DAW, you might want to check out the free Fender Studio One-based DAW that comes with a lot of amp, pedal and cab emulations. (Fender now own Presonus).

It’s limited in operation in things like track numbers, but probably similar to the Studio One bundle.

https://uk.fender.com/pages/fender-studio

[cton58]

Thanks all.
I suppose I should have mentioned in my original post….
when I plug my guitar (passive PU) into the interface, I have to crank the gain knob on the interface to just past 4 o’clock to get a green blink. And with the guitar damn near cranked.
I was thinking any pedal would give me some “boost” and some playroom with the input knob.
Thanks for all the information.

[ef37a]

Thanks all.
I suppose I should have mentioned in my original post….
when I plug my guitar (passive PU) into the interface, I have to crank the gain knob on the interface to just past 4 o’clock to get a green blink. And with the guitar damn near cranked.
I was thinking any pedal would give me some “boost” and some playroom with the input knob.
Thanks for all the information.

Assuming the interface (which is?) has the usual arbitrary 1 to 10 control knob scale, a "4" is a perfectly decent position to use. I assume a higher setting does not cause any noise? I have had a good half dozen AIs over the years and never had one which could not grab a very decent recording at a good level (~-20dBFS of course!) from, in our case, a Mexican Strat. Noise levels are ALWAYS limited by guitar pickup.

Why not have the guitar all the way up? That usually gives the best results.

The very first generation of the highly regarded Focusrite 2i2 had excessive instrument input gain and there were many reports of nasty "cracking up".
Always best to err on the side of lower gain and higher headroom. You can always boost post tracking digitally and not compromise the signal to noise ratio.

Dave.

[Wonks]

Unfortunately the interface manual doesn't give maximum input levels for the instrument and line inputs, just gain adjustment ranges. "-24 to +27 dB on the instrument inputs". So at 4 o'clock that's probably around 20dB of gain.

10dBu is the overall 0dBFS level but there's no other info as to how exactly that relates to the mic, line and instrument inputs.

And no indication as to what level the green signal LED turns on at. It really is a technically useless manual. Full of a lot of seemingly 'useful' information about how to EQ different instruments, which is an utter waste of time, but lacking in useful stuff that would help you to set the interface up correctly.

[Wonks]

What are the signal levels on the recordings like with the gain knob cranked up like that?

You can use the BD-2 to give some extra boost with the gain knob down and the level up, but it's probably still colouring the guitar sound a little bit.

I'd probably set the interface gain to about 2 o'clock and see what it sounds like with the BS-2 volume turned up.

If it works, you may be better off getting a clean boost pedal for the job which should leave the guitar signal uncoloured by any tone filtering in the pedal itself.

The BD-2 gives rather a humped frequency response across the whole frequency spectrum, but is reasonably flat (with the tone control most of the way up) across the pickup output of a clean guitar (e.g. a vintage Strat-style single coil drops off quickly above 4kHz). But there are flatter response clean boosts which won't push the mids up a bit.

https://www.analogisnotdead.com/article ... e-boss-bd2

[cton58]

What are the signal levels on the recordings like with the gain knob cranked up like that?

https://www.analogisnotdead.com/article ... e-boss-bd2

Wonks. (And all.)Thank you for your help.
Oh it registers, say -9 in that range. So I try to shoot for -14/-18, but when I turn down the guitar or volume of the AI trim, I lose the green input light. And I feel like the AI is not getting a proper input signal. Yeah, I’m splitting hairs.
And if I turn up the input one little, click…..BAM RED.
Maybe I should just go back to using two cassette recorders like I did in 1975.

[Wonks]

I'd probably go by the DAW metering. -9 dBFS is fine, as long as you aren't getting excessive noise from having the gain up.

All you can do is have a go with the BD2 and see what you think. Maybe take the gain down that one notch and then add a bit of volume with the BD2. As long as you don't continuously have the LED in the red you're in no danger of damaging the electronics. Some line outputs from studio equipment can drive at up to +26dBu (about 15v) when pushed hard, which is why the manual says strong line input signals 'could damage the interface', but even the BD2 with everything turned right up won't be producing enough voltage from the signal to do any damage.

[Hugh Robjohns]

Ignore the lights on the interface. The meters on your DAW are far more meaningful, so use those as you adjust the input gains on the interface.

Aim to get the average signal level hovering around -20dBFS, and try to keep peaks to -10dBFS or below.

The odd kick up to -6dBFS won't hurt, but it's far better to maintain a generous headroom margin so that you really don't have to worry about the risk of overload all the time!