Digital desk that can bus a mic input to more than 1 preamp?

[Greg Cameron]

Hi guys. I was curious if there's a desk out there that can bus a physical XLR input to more than one mic pre. Seems doable, but I'm not aware of any. On my Venue, the channel mapping is post preamp only. So if I bus an input to more than one processing channel, the gain on any of those channels affects all channels.

Thanks.

 

[John Roberts]

Re: Digital desk that can bus a mic input to more than 1 preamp?

Just because it is possible, doesn't mean it is practical or cost effective. It is not clear to me what possible benefit accrues from doing that, that way.

If you want to send one input to two channels, it is far easier and cheaper to do that in the digital domain. Relative gain between the two stems can be accomplished with a simple multiply in the digital domain. The mic preamp with A/D convertor is a major cost element inside a digital console. For one-off special applications use a splitter cord. For larger parallel operations that needs to burn 2x the number of inputs , just use two consoles.

Note; In my future vision, console inputs will automatically manage clipping and nominal gain setting, Console input trims would be relative gain, and automatically compensate for clipping events and the like. There would be little reason for anybody to mess with first stage mic pre gain.


JR

 

[Greg Cameron]

Re: Digital desk that can bus a mic input to more than 1 preamp?

Hi John. It was merely an inquiry. It would be a nice convenience but I suspect it would entail some costs that make it impractical. I was just curious to see if it's actually been done. The benefit would be doing monitors from FOH where you want completely independent control of mains vs. monitors. Of course, the cheapest cheapy way to do it is Y the mic to the inputs. But it would be a nice feature to just be able to route a single input to multiple pres on the fly. That is all... (M*A*S*H style voice).

 

[Jason Glass]

Re: Digital desk that can bus a mic input to more than 1 preamp?

Hi Greg,

I just want to mention that using one preamp and splitting digitally actually solves the age-old problem of an impedance drop that a given microphone (or other source) sees when its signal is split parallel to multiple preamps. Mics only perform to their ideal specifications when connected to optimal input loads.

 

[Jens Bacher]

Re: Digital desk that can bus a mic input to more than 1 preamp?

The Midas DL431 feeds each physical input to 3 different preamps... Midas Consoles | DL431

 

[Greg Cameron]

Re: Digital desk that can bus a mic input to more than 1 preamp?

Hi Greg,

I just want to mention that using one preamp and splitting digitally actually solves the age-old problem of an impedance drop that a given microphone (or other source) sees when its signal is split parallel to multiple preamps. Mics only perform to their ideal specifications when connected to optimal input loads.

While I agree on paper that splitting mics potentially alters performance, in practice I've never noticed a different with 2 or even 3-way splits. Has anyone else out there noticed a performance hit? It would be an interesting experiment to conduct with someone that has some time on their hands to find out how many splits you need before there's an audible change in performance or degradation of sound.

I agree that splitting in the digital domain post A to D takes possible coloration out of the equation. But then you're stuck with non-independent channel gains again. Understand though that I'm just playing devil's advocate here.

 

[Greg Cameron]

Re: Digital desk that can bus a mic input to more than 1 preamp?

The Midas DL431 feeds each physical input to 3 different preamps... Midas Consoles | DL431

Ah yes, that would be the beast.

 

[John Roberts]

Re: Digital desk that can bus a mic input to more than 1 preamp?

Hi John. It was merely an inquiry. It would be a nice convenience but I suspect it would entail some costs that make it impractical. I was just curious to see if it's actually been done. The benefit would be doing monitors from FOH where you want completely independent control of mains vs. monitors. Of course, the cheapest cheapy way to do it is Y the mic to the inputs. But it would be a nice feature to just be able to route a single input to multiple pres on the fly. That is all... (M*A*S*H style voice).

But do you need two complete independent mic preamps connected to one mic, or can you accomplish what you want with a post preamp split with separate gain trims. As I have speculated before, it should be possible to allow for independent gain trims even using a common preamp, taking advantage of the computer brain in the digital processing, to prevent one guy's tweaks from affecting the other.

Hypothetically one could overlay a virtual monitor mixer on top of the FOH mixer if there is enough computing horsepower. You just need to page between them, or perhaps access the second via a remote control surface.

I am looking at this from the $$$ cost side, and it takes a bunch more money to replicate preamps, than to replicate processing.

JR

PS: For the mix engineers that want to overdrive their mic preamps for some musical effect, that the other mix engineer sharing the console doesn't want, I do not see an easy solution, besides shooting the mix engineer that likes the sound of preamps clipping.

 

[Peter Morris]

Re: Digital desk that can bus a mic input to more than 1 preamp?

Hi guys. I was curious if there's a desk out there that can bus a physical XLR input to more than one mic pre. Seems doable, but I'm not aware of any. On my Venue, the channel mapping is post preamp only. So if I bus an input to more than one processing channel, the gain on any of those channels affects all channels.

Thanks.

Yes - Allen Heath iLive will do exactly what you want – e.g.ch inputs 1-32 to channels strips 1-32 & 32-64, channel 33-64 can use digital gain trim to adjust the gain without effecting channel 1-32.

And you can mix 33-64 side of stage on your laptop if you like.

Midas Pro series can also do a similar trick with the inputs.

 

[Nick Boulton]

Re: Digital desk that can bus a mic input to more than 1 preamp?

While I agree on paper that splitting mics potentially alters performance, in practice I've never noticed a different with 2 or even 3-way splits. Has anyone else out there noticed a performance hit? It would be an interesting experiment to conduct with someone that has some time on their hands to find out how many splits you need before there's an audible change in performance or degradation of sound.

I agree that splitting in the digital domain post A to D takes possible coloration out of the equation. But then you're stuck with non-independent channel gains again. Understand though that I'm just playing devil's advocate here.

There is a difference in tone and signal level when hanging more mic pres off a mic. I've done numerous festivals where we've had multiple boards at front of house and on stage and the difference is very noticeable, especially if there's 120m of analogue multicore involved too. As an extreme example, a 5 way analogue split (H3k and pro6 at monitors, h2k and pro9 at foh, and a record split going to a vi6) completely changes the characteristics of the mics involved. Unplugging the multipins to the unused boards (turning it into a 2 or 3 way split) made everything sound 'normal'. Even a four way split without the analogue run to the H2k sounded a little bit off.

 

[Ã￾rni F. Sigurðsson]

Re: Digital desk that can bus a mic input to more than 1 preamp?

The Midas DL431 feeds each physical input to 3 different preamps... Midas Consoles | DL431

Not correct, it has a 3way split, but only feeds into two preamps. The third output goes to the XLR's on the front that incoming desks and broadcast can hook into.

Both preamps (A and B) then have a post-preamp analog line out (along with the AES50 outputs)

We have 12 of those at work =)

As said, both Midas Pro and iLive (and probably others) give you both analog gain and digital trim.

 

[Jens Bacher]

Re: Digital desk that can bus a mic input to more than 1 preamp?

Not correct, it has a 3way split, but only feeds into two preamps. The third output goes to the XLR's on the front that incoming desks and broadcast can hook into.

Both preamps (A and B) then have a post-preamp analog line out (along with the AES50 outputs)

We have 12 of those at work =)

As said, both Midas Pro and iLive (and probably others) give you both analog gain and digital trim.

I thought Iceland had stopped spending money on luxury goods a couple years ago 8O~8-O~:shock:

The third "output" is still a preamp, just at fixed level ;-) Read the A&E specs: Midas Consoles | DL431

The ilive, just like any other digital desk, only has one A/D converter pr. physical input.

 

[John Roberts]

Re: Digital desk that can bus a mic input to more than 1 preamp?

There is a difference in tone and signal level when hanging more mic pres off a mic. I've done numerous festivals where we've had multiple boards at front of house and on stage and the difference is very noticeable, especially if there's 120m of analogue multicore involved too. As an extreme example, a 5 way analogue split (H3k and pro6 at monitors, h2k and pro9 at foh, and a record split going to a vi6) completely changes the characteristics of the mics involved. Unplugging the multipins to the unused boards (turning it into a 2 or 3 way split) made everything sound 'normal'. Even a four way split without the analogue run to the H2k sounded a little bit off.

Back at Peavey the monitor consoles with hardwire splits also had >> than the nominal 2k mic input termination so when connected in parallel with a FOH console it wouldn't load down the mic. Active mic preamps naturally have high input impedance and use resistor terminations to drop down to the 2k. So easy to make it higher and not load down the mic, that even Peavey could do it...

Hopefully big dog monitor consoles can figure that out too.

JR

 

[mackerr]

Re: Digital desk that can bus a mic input to more than 1 preamp?

Yes - Allen Heath iLive will do exactly what you want – e.g.ch inputs 1-32 to channels strips 1-32 & 32-64, channel 33-64 can use digital gain trim to adjust the gain without effecting channel 1-32.

Pretty much any digital console can do that, and while you can adjust the digital gain without changing the other channels, you cannot change the analog gain without changing them. That is what Greg is looking for.

Mac

 

[Peter Morris]

Re: Digital desk that can bus a mic input to more than 1 preamp?

Pretty much any digital console can do that, and while you can adjust the digital gain without changing the other channels, you cannot change the analog gain without changing them. That is what Greg is looking for.

Mac

Thanks Mac …. I did not read it properly this morning and posted in a hurry.

FWIW I built a 48-way splitter box with 2 sets of 5M tails that “Y” cord the inputs together do this. It’s a cheap and cheerful solution but seems to work just fine. It’s been used more often than I expected.

Much cheaper than a DL431...

Peter

 

[Ã￾rni F. Sigurðsson]

Re: Digital desk that can bus a mic input to more than 1 preamp?

I thought Iceland had stopped spending money on luxury goods a couple years ago 8O~8-O~:shock:

The third "output" is still a preamp, just at fixed level ;-) Read the A&E specs: Midas Consoles | DL431

The ilive, just like any other digital desk, only has one A/D converter pr. physical input.

Why do you think we are broke

Ok you win =) Still a bit sceptic if a fixed -6db transformer output is technically a preamp but maybe there's some magic to it

 

[John Roberts]

Re: Digital desk that can bus a mic input to more than 1 preamp?

Pretty much any digital console can do that, and while you can adjust the digital gain without changing the other channels, you cannot change the analog gain without changing them. That is what Greg is looking for.

Mac

But... there shouldn't be any difference between analog gain and digital gain as long as you operate the preamp in it's linear region (below clipping).

If selective clipping of input stages is considered a useful feature, it will cost you in duplication of a relatively expensive signal block.

JR

 

[Kip Conner]

Re: Digital desk that can bus a mic input to more than 1 preamp?

I think that you just do what you have to do to get what you need. I have to mix monitors and foh from my LS9 and I use passive y cables in the doghouse to split the channels instead of using the digital gain. The gain structure from the monitor channels are too different than the FOH channels to try to use the digital trim correctly. I don't really notice anymore because I've been doing it so long. I do have an 4 channel mini split, but it's just one more piece of gear to patch in.

 

[Darren Scaresbrook]

Re: Digital desk that can bus a mic input to more than 1 preamp?

I think that you just do what you have to do to get what you need. I have to mix monitors and foh from my LS9 and I use passive y cables in the doghouse to split the channels instead of using the digital gain. The gain structure from the monitor channels are too different than the FOH channels to try to use the digital trim correctly. I don't really notice anymore because I've been doing it so long. I do have an 4 channel mini split, but it's just one more piece of gear to patch in.

Can someone explain the need for differing gain structures in a desk for monitors and foh?
I have never had the need to do this. Optimum gain structure should be the same regardless, the electronics don't care if the signal is going to a wedge or foh cab. For channel eq, compression etc, yes, I see the benefit, but the input trim should always be set for maximum s/n and to allow max dynamic range.
Darren

 

[Jordan Wolf]

Re: Digital desk that can bus a mic input to more than 1 preamp?

Can someone explain the need for differing gain structures in a desk for monitors and foh?
I have never had the need to do this. Optimum gain structure should be the same regardless, the electronics don't care if the signal is going to a wedge or foh cab. For channel eq, compression etc, yes, I see the benefit, but the input trim should always be set for maximum s/n and to allow max dynamic range.
Darren

The concern isn't usually with "correct" settings for best S/N ratio, it's more about the fact that changing the headamp also causes changes in that input's aux sends…not good for Monitors, especially if you're on the verge of feedback already or - possibly, even worse - on IEMs. Small changes can make a BIG difference in the mix and safety of the performers' mixes.