Wasn't sure if this should have gone in the PC music forum, but here goes...

I've an MBox 2 Pro, and just unexpectedly managed to get a DAV Broadhurst Gardens No.1 preamp. I've started trying them together (mainly vox and acoustic strings, various mics), which hasn't been as straightforward as I was expecting. :-/

The only successful connections I've achieved are via the (unbalanced) Channel 1 and 2 DI ins on the MBox, and the Aux in channels (3 & 4). The latter pair have the disadvantage that they share a gain pot, tho I believe they're TRS unlike the unbalanced DI ins. They also don't have channels 1 & 2's -20db pad. (Something I hadn't expected is that I've not been able to get a signal using either an XLR or TRS in the back socket for channels 1 and 2, with the channels switched to DI: I'd thought this would be the best way to circumvent the MBox preamps).

My problem's been that the BG1 signal's so hot (and this isn't the one with the +6db mod!), the MBox is peaking even with the gain down to 'zero'. I was anticipating that I could use the BG1's -26db pad - but (perhaps obviously in retrospect!) it looks like this applies to input levels.

This means my only two options seem to be: (a) record at a level on the BG1 where the input isn't close to causing the green input level LED to flicker - which I'm guessing will mean less than optimal sound and high relative noise, or (b) use the MBox unbalanced DI ins, and do my best with the MBox's -20db pad.

Neither seems ideal: I wondered if anyone's had experience of using the two bits of kit together (am I missing something obvious?), and/or had any advice on how I could get the best from the DAV with the MBox.

Thanks! Any help much appreciated,

Ru

You need to go line in either via the combi jacks or the TRS.

If it's still too hot an in-line pad should sort you out.

You should use the balanced line inputs for chanel 1/2 via the channel 1/2 combi jack inputs -- the TRS sockets in the centre of the XLRs.

Select LINE input and PAD. Set the gain control to the minimum position. In this condition the inputs can accommodate inputs up to +21dBu which should be ideal for the BG1.

The unbalanced DI inputs should also be able to cope with +21dBu with the pad switched in, but you'd be better off using the balanced inputs rather than the DI inputs if you can.

The aux line inputs appear to only be able to handle a maximum of +10dBu which is a little low for the BG1.

hugh

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Technical Editor, Sound On Sound

Quote Hugh Robjohns:

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You should use the balanced line inputs for chanel 1/2 via the channel 1/2 combi jack inputs -- the TRS sockets in the centre of the XLRs.

Select LINE input and PAD. Set the gain control to the minimum position. In this condition the inputs can accommodate inputs up to +21dBu which should be ideal for the BG1.

The unbalanced DI inputs should also be able to cope with +21dBu with the pad switched in, but you'd be better off using the balanced inputs rather than the DI inputs if you can.

The aux line inputs appear to only be able to handle a maximum of +10dBu which is a little low for the BG1. Hugh

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Oops - thanks for relocating this in the right forum!

Thanks RegressiveRock and Hugh! Hugh: I've got that at least working now, and at first try levels now seem workable. Sorry if I'm being dense: how do I select LINE input? Will use of the TRS sockets automatically select Line input and bypass the MBox pres, or is there something else I need to do (in the hardware setup in ProTools?) to select line input? This is what threw me: I haven't been able to get a handle on how the MBox chooses whether the input's Line level. That's why I'd been trying to use the DI switches (which look like they only apply to the unbalanced front-panel DI sockets)

Cheers, Ru

If it works anything like any other device I have used then the centre TRS in the combi IS line level - there isn't any selecting tto be done other than, I suspect you should not select DI

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Matt
www.krcollective.org

Quote Rustrings:

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how do I select LINE input?

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Sorry -- my description was a little ambiguous wasn't it?

The Line mode is selected automatically when you plug something into the central jack socket of the combi-XLR.

So the fron panel selector needs to be in the Mic/line mode rather than the DI mode.

hugh

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Technical Editor, Sound On Sound

Quote Hugh Robjohns:

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The Line mode is selected automatically when you plug something into the central jack socket of the combi-XLR. So the front panel selector needs to be in the Mic/line mode rather than the DI mode.

hugh

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Thanks - v. clearly put! Things make much more sense knowing that! (I'd never twigged that TRS means line in for audio kit).

Cheers, Ru

I've got the same setup and Hugh's method is the way to go.

However, I use the pad on the BG-1 rather than the one on the MBox. This makes the gain much more 'normal' when tweaking, as opposed to the red-hotness of the 'un-padded' signal. Damn that box has got gain!

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"Those who have ears to hear, will hear"
-Dmitri Shostakovitch

Quote Sonny Williamson:

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Damn that box has got gain!

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You're not kidding!! At one stage I was considering a box with the +6db mod. I'm so glad I got cautious!! Hugh - I've been running it now as you suggested, and it seems to be working nicely, although still quite near the top of the scale with a couple of my mics even with the 20db pad and the MBox gain to its lowest setting (I've found myself using mic pads as well, which I've never had to before!). I'll try your suggestion Sonny (though doesn't that reduce the input signal, rather than the output?) The sound difference is subtler than I was expecting, but noticeably fuller than the MBox. I'm going to start sound-treating my room now so I can do it justice.

Many thanks for all the advice.

Quote Rustrings:

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Quote Sonny Williamson:

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Damn that box has got gain!

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You're not kidding!! At one stage I was considering a box with the +6db mod. I'm so glad I got cautious!! Hugh - I've been running it now as you suggested, and it seems to be working nicely, although still quite near the top of the scale with a couple of my mics even with the 20db pad and the MBox gain to its lowest setting (I've found myself using mic pads as well, which I've never had to before!). I'll try your suggestion Sonny (though doesn't that reduce the input signal, rather than the output?) The sound difference is subtler than I was expecting, but noticeably fuller than the MBox. I'm going to start sound-treating my room now so I can do it justice.

Many thanks for all the advice.

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Why dont you just turn the DAV down? - obviously within reason
Thats all I do

Had quite a conversation with Mick at DAV about this and he said that in a way turning it down was no bad thing in that the electronics were doing less amplifying

Oh

that last anonymous was me

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Matt
www.krcollective.org

Quote Anonymous:

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Why dont you just turn the DAV down? - obviously within reason. Thats all I do. Had quite a conversation with Mick at DAV about this and he said that in a way turning it down was no bad thing in that the electronics were doing less amplifying

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I've been wary of hiking the signal to noise ratio. Having said that, the DAV so far seems remarkably quiet, so maybe it's not a problem...

So are DAV actually recommending running it without the green LEDs flickering?

Cheers, Ru

Am about to attempt something similar to this in just over a week recording choir and organ in a church.

Am planning to use my DAW from home (ProTools LE on PC), coupled with a few bits of hire kit. The initial rig looks something like this:

- Mbox 1 (original Mbox with Focurite pres)recording 2 channels into Protools
- AKG C426 stereo mic

I'm thinking of maybe hiring a separate mic preamp - one of the hire companies I'm in touch with (FXrentals) have Massenburg 8300s (amongst many others), another has a Nagra KAT 15 for much lower price.

Will coupling just a higher-end preamp to the MBox line-ins make a difference to the sound quality?

I'm also possibly thinking of hiring a stand-alone a/d converter to pair with a decent mic-pre and going into the SPDIF on the the Mbox - again, have a choice at the lower end here of an RME ADI-2, a PRISM DA1 or an APOGEE AD16.

Just wandering where I need to splash out to have an impact on the audio quality going into ProTools? This is a zero-budget session for a composer friend of mine to get some demos down, but we're working with a pretty good scratch choir, excellent organist + pipe organ in a wonderful sounding space so want to get the most out of the day without racketing up the equipment costs too much.

Any suggestions on maximising my signal path mixing 'pro' with 'prosumer' gear?