Geting from Mixer to Sound Card on the cheap...

M

MagicMatt

New member
I have a Peavey PV14 mixer that we use with the band when we perform live. It's used for vocals, and to provide a bit of extra volume for the drums, and the bass to spread the sound and reduce the booming effect in some rooms. As far as I can tell, the Inserts are TRS for send/return at +4dBu unbalanced.

I have an old 8-channel recording interface (DSP24 C-PORT Windows XP system) that has unbalanced line-level inputs, which I think are computer level (-10dBV).

My idea is that I could massively reduce the amount of equipment if I want to do a live recording, if I patch into the mixing desk, as then I could just use mics on the guitar amp and overhead on the drums into the Sound Card, and take the rest via a set of patch cables.

I've come up with this idea...

My mixer attenuator.jpg

...would it work, or am I missing something or risking damaging anything through lack of knowledge?
 
Sounds possible. But I bet it won't sound so good. :(


Even when going the cheap route, there are many other things to consider. This is way cheap. Give it a shot, then realize it is not going to give the results you would like. Trust me, I have been there. It will likely not be worth the time you spent.

Forget the PV14 altogether for recording man. IMO you are going to just waste time and money..
 
jimmys69 said:
Sounds possible. But I bet it won't sound so good. :(
Click to expand...

Why not? The mic pre on the PV14 is pretty good. Is it due to my wiring plan, or something else?

jimmys69 said:
Forget the PV14 altogether for recording man. IMO you are going to just waste time and money..
Click to expand...

We already have the PV14, and it serves us very well, hence why I was hoping to utilise what we have rather than spend out on a lot more gear, which means more stuff to carry around, more time to set up and pack away, and of course a lot more expense.

Could you please elaborate on why you think it wont sound so good?
 
Yes, as with most lower price point mixers meant for live use such as this, the preamps are not really meant to be as clean as you would like. That is not me giving you a yes or no as to whether it will be good enough for you. I am just expressing that I doubt it will be as good as I would want myself. Give it a shot and please let us know how it works for you.

You have nothing to lose by trying. :)
 
jimmys69 said:
Yes, as with most lower price point mixers meant for live use such as this, the preamps are not really meant to be as clean as you would like.
Click to expand...

Ah, ok. Well I'm not expecting studio quality, because if we wanted that we'd probably go into a studio! The idea is basically to get something that sounds good, rather than something that sounds superb. The main thing really was whether it would just get the sound into the card ok, or whether I was doing something monumentally stupid with my wiring. :)

I'll give it a go and see what happens.
 
Maybe you should just connect a source to the PV14, set the gain correctly, connect the insert to the interface then look at the record level and listen to the results. A 0dBVU signal should come out to around -18dBFS if the inputs are +4dBu. If it's around -6dBFS then the inputs are probably -10dBV.
 
bouldersoundguy said:
Maybe you should just connect a source to the PV14, set the gain correctly, connect the insert to the interface then look at the record level and listen to the results. A 0dBVU signal should come out to around -18dBFS if the inputs are +4dBu. If it's around -6dBFS then the inputs are probably -10dBV.
Click to expand...

Hoiw would I determine I have an appropriate level signal? If I plug in my synth, and adjust the gain until the clipping LED starts to flicker on the desk, would that be right?
The reason I'm assuming I need some attenuation is that everything else on the desk is +4dBU, and if I plug in a HiFi minidisc recorder to the outputs, it clips before the desk levels hi the orange zone.
 
Hi Matt,
Yes that will work. Small point, internal mixer levels are rarely +4dBu, more like -2dBu (615mV) so you might want to revise those resistor values!

The DSP24 is a forerunner to ESI's 1010 and I have the 1010e and while it has its foibles, 1)I got it cheap and 2) I have no issues with the sound quality.

But back to levels. If you are going to do this thing properly you will put the attenuators in a box and have jacks in and out? If so use multiturn 10k presets, little more money than 2 Rs per, and you will be able to set each channel for a precise level.

I NEVER dissuade peeps from DIY electronics! That is what MADE the recording industry, especially here in Britain. Most of the people posting here probably can't change a 13A PT and don't own a test meter....We are all doomed!

Dave.
 
ecc83 said:
Small point, internal mixer levels are rarely +4dBu, more like -2dBu (615mV)
Click to expand...

Ahh, that's handy to know!

However, with 24bit, giving myself some headroom is probably sensible, and the noise level should easily be low enough for my needs.

I didn't realise that the ESI 1010 was so similar! I'm wondering if he chips are the same and whether the drivers could be convinced o work with the DSP24... unlikely but worth a shot. I'm stuck on XP with the DSP24 sadly.

My plan was to solder resistors into the plugs - cheap and cheerful and low cost, effectively giving myself a multicore snake. If it worked in principle, then yes I'd more than likely then move on to make something a bit more substantial. The thing here is I want it to be as portable as I can get it. I'd actually prefer a self-contained multi-rack recorder, but the budget just doesn't stretch to one, and somehow I don't think I'd be able to DIY one of those!
 
MagicMatt said:
Hoiw would I determine I have an appropriate level signal?.
Click to expand...

Read the mixer's manual, especially the part about setting gain.

MagicMatt said:
If I plug in my synth, and adjust the gain until the clipping LED starts to flicker on the desk, would that be right?
Click to expand...

On most mixers you set the gain to make the meter read 0dBVU. Read your manual.

MagicMatt said:
The reason I'm assuming I need some attenuation is that everything else on the desk is +4dBU, and if I plug in a HiFi minidisc recorder to the outputs, it clips before the desk levels hi the orange zone.
Click to expand...

As ecc points out, internal levels, including insert points, are typically lower. I'm pretty sure one board I work on regularly has tape I/O at -10dBV. Read your manual and/or do the 3 minute experiment I outlined previously.
 
bouldersoundguy said:
Read the mixer's manual
Click to expand...

I did, and it's pretty useless, hence why I was trying to determine things by other means.

bouldersoundguy said:
one board I work on regularly has tape I/O at -10dBV
Click to expand...
This doesn't, it has Main Out at +4dBU - one of the few things that the manual does say... however that's irrelevant because I want the channels separately, not the downmix.

I'm not a complete idiot. I have downloaded the manual and studied it.

Your 3 minute experiment is actually nearer to 2 hours, since it would involve driving to another location, retrieving the mixing desk and cables from the lockup, setting it up, doing the experiment etc. Not that I do not appreciate the suggestion, but I am just pointing out there are reasons why I'm trying to get everything planned out properly etc. before I go to try it all out.
 
Hi again Matt,
I use my 1010e on an XP PC in my living room. Total overkill for TV sound but one reason is because it did not seem happy on Win 7 so I would keep XP for now at least.

Re the inserts. A guy was on a forum (might have been HR) some months ago and wanted to do a similar thing with a mixer and an M-A 1010lt card and I got into the problem a bit and drew up a back of envelope switching system so that you could have a record feed from an insert but also use it as a playback circuit for post tracking mixdown. I have also thought that such a setup could be useful with a standalone multitracker like the Allen and Heath unit.

Good luck with the project and feel free to PM if you think I might be able to help.

Pitting time here now.

Dave.
 
MagicMatt said:
I did, and it's pretty useless, hence why I was trying to determine things by other means.
Click to expand...

It does seem rather dumbed down. Try this for setting input gain: set the channel fader to 0, set the master fader to 0 and turn up the channel gain until the main meter reads about 0. That's more or less how it works on many, many mixers, though usually using the solo function.

MagicMatt said:
This doesn't, it has Main Out at +4dBU - one of the few things that the manual does say... however that's irrelevant because I want the channels separately, not the downmix.

I'm not a complete idiot. I have downloaded the manual and studied it.

Your 3 minute experiment is actually nearer to 2 hours, since it would involve driving to another location, retrieving the mixing desk and cables from the lockup, setting it up, doing the experiment etc. Not that I do not appreciate the suggestion, but I am just pointing out there are reasons why I'm trying to get everything planned out properly etc. before I go to try it all out.
Click to expand...

I couldn't have known that. Most people here have their gear at home to record with, being homerecording.com. Much of my gear is in storage as well as it's mostly for gigs, so I understand that. The point is, as ecc indicated, it's entirely possible the inserts are at -10dBV. Before plugging in the iron you could try asking if anyone on the board has one and can do the experiment for you. You may just need to build insert tap cables without the attenuators.
 
bouldersoundguy said:
It does seem rather dumbed down. Try this for setting input gain: set the channel fader to 0, set the master fader to 0 and turn up the channel gain until the main meter reads about 0. That's more or less how it works on many, many mixers, though usually using the solo function.
Click to expand...

Excellent, thanks, I'll try that method, thanks. :)

This is going to more an at gig recording, but at home mix down, burn to CD, etc.
I'll try making up 4 plain, 4 attenuated cables (resistors are dirt cheap anyhow) then I can swap around and see what works.


ecc83 said:
Hi again Matt,
...I got into the problem a bit and drew up a back of envelope switching system so that you could have a record feed from an insert but also use it as a playback circuit for post tracking mixdown.
Click to expand...

What a cool idea! I can see how that would be really useful if the desk were at home to use. :)
 
Ok, I have done some experimenting. Setting the desk up as you suggested, with the desk reading 0dB, the sound card is maxed out completely and distorting. When I lower the gain control so the meter on the desk is hitting the -12dB mark, the sound card is just touching it's 0dBFS point. I guess it's time to make that attenuation box! :)
 
MagicMatt said:
Ok, I have done some experimenting. Setting the desk up as you suggested, with the desk reading 0dB, the sound card is maxed out completely and distorting. When I lower the gain control so the meter on the desk is hitting the -12dB mark, the sound card is just touching it's 0dBFS point. I guess it's time to make that attenuation box! :)
Click to expand...

So now you know that you need 30dB, not 12dB, of attenuation so 0dBVU on the mixer's meter ends up at -18dBFS in the computer. Good thing you did the test.
 
I see this a lot. So you finally discovered why professional recording studios have all that expensive equipment. You need a AD/DA converter. They run about $100 to $500 depending on the number of inputs. I use an eight channel M-Audio that ran about $500. Pay attention to your question: cheap ideas produce cheap sounds.
Rod Norman
Engineer

MagicMatt said:
I have a Peavey PV14 mixer that we use with the band when we perform live. It's used for vocals, and to provide a bit of extra volume for the drums, and the bass to spread the sound and reduce the booming effect in some rooms. As far as I can tell, the Inserts are TRS for send/return at +4dBu unbalanced.

I have an old 8-channel recording interface (DSP24 C-PORT Windows XP system) that has unbalanced line-level inputs, which I think are computer level (-10dBV).

My idea is that I could massively reduce the amount of equipment if I want to do a live recording, if I patch into the mixing desk, as then I could just use mics on the guitar amp and overhead on the drums into the Sound Card, and take the rest via a set of patch cables.

I've come up with this idea...

View attachment 87689

...would it work, or am I missing something or risking damaging anything through lack of knowledge?
Click to expand...
 
Jeez, Rod, let the guy have his fun. He just wants to record his gig. He'll find out soon enough if it sounds bad enough to invest in better gear. All it will cost him is some cheap parts and a little soldering time. That's the best way to learn, by doing, failing and figuring out what happened.
 
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