# External meter bridge?



## jkowtko (Jul 14, 2008)

After three days I'm really liking the Soundcraft LX7 I just purchased for the theater. The art-deco buttons and pot knobs have really grown on me, and the response of the controls is very smooth overall. 

However, the lack of a meter bridge is killing me, and I'm really surprised that there are so few low-end boards with meter bridges.

Question -- does anyone know of an external meter bridge that I can buy, or build with parts, that would plug into the channel direct outs?

Currently I have a bunch of Behringer MDX4600s plugged in for compression, and the input meter on those servers as a makeshift meter bridge, but the placement and orientation of the MDX4600s and their meters makes it difficult to use them for true metering purposes. It would be great to find something I could mount directly above the board channel inputs.

Any help here would be much appreciated.

Thanks. John


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## mixmaster (Jul 14, 2008)

I've got a couple LED meters around here somewhere, I just took them out of one of the house racks. They were measuring output to the amp rack. I suppose you could use 24 of them. If I can find them again I'll reply to this and let you know what they were.
Are you sure you want to use the direct outs though. It's been a while since I've used that board but I thought the D.O. were post fade?


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## jkowtko (Jul 14, 2008)

Only channels 1-16 have DOs ... but there's a Pre/Post switch on them all 

Yes, please send me the info on the LEDs if you find them. I can make a 16 channel meter bridge.

Thanks. John


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## mixmaster (Jul 15, 2008)

jkowtko said:


> Only channels 1-16 have DOs ... but there's a Pre/Post switch on them all
> 
> Yes, please send me the info on the LEDs if you find them. I can make a 16 channel meter bridge.
> 
> Thanks. John



Surprisingly enough I found them! I cleaned out the boneyard this AM and actually put stuff away. Anyhow, What I took out of my rack is an RDL RU-SM16. They are two channel, 16 led meters that can be mounted 3 to a frame (total of six meters) to fit in a single rack space. However after checking the RDL website, these are 200kohm devices, and may not work for your application. I don't know what the output specs are on the DO for your LX7. Everywhere we use them, it's a fairly hot line level. Check them out here:
- RU-SM16 Dual Audio Meter - Average/Peak/Hold

If this won't work, I'd continue to look for other ideas on the RDL site. They have a lot of little solution boxes and I've found all of their stuff to be good quality, if slightly expensive. Best of luck


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## jkowtko (Jul 15, 2008)

The LX7 has 75 ohm DOs, so that should be fine.

I don't want to rack mount these -- I already have the MDX4600s sitting in the rack. I wanted to create an home-built meter bridge to mount just above the input channels and position each LED bank above it's corresponding channel. If I turn these on side they should be narrow enough (1.75" per two channels) to fit within the board's channel width.

However -- I just looked at pricing -- these are very expensive ... $200/unit, that's $100/channel! Might as well go buy a Spirit Live 8 ... I'm looking for something for about $2/channel, that I can solder my own wires on, etc 

Thanks. John


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## mixmaster (Jul 16, 2008)

RDL is not cheap, that's for certain.
If what you want is component level, I usually find Mouser to be a pretty reasonable place to start, but I warn you, their website is a bit awkward.


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## jkowtko (Jul 18, 2008)

Here's what I'm thinking of ...

10-LED Bargraph Meter PCB adjustable levels, multi-use - eBay (item 330198026902 end time Aug-10-08 12:55:26 PDT)

however this particular unit is just a bit wider than the channel strip on the LX7, so if you know of any others like this please post the information.

Thanks. John


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## waynehoskins (Jul 19, 2008)

It doesn't have a 4-bar meter right at the fader? Those things ("idiot lights") grow on you fast. I wonder sometimes how I lived without them for so long.


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## jkowtko (Jul 19, 2008)

Allen & Heath boards have the 4-segment LED. GL2200, GL2400 and up. Those are higher on my list than the Soundcraft LX7, but they're a lot more expensive, even used. And even 4 segments still does not provide as much feedback to the user as a full 12 segment bargraph (-20, 0, +6, peak) since a lot of my monitoring happens between the -20 and 0 range.

Then some boards have a signal and peak (2 LEDs), and most of the lower-end boards just have a peak indicator.

The LX7 appears to be the entry level for Soundcraft's medium level format, and looking at their price structure and the GB line and how it compares to A&H, it looks like they had to keep a lot of features out of the Live4/LX7 series to keep it clearly distinguished from the Live8 and GB line, in order to prevent cannibalism. Unfortunately, that's a standard marketing strategy ... offer a full line of products but clearly distinguish between them on cost and features so you don't overpack the lower-end models and lose sales on the upper end.

It would be awesome if Soundcraft were to offer a meter bridge for the LX7 -- even at $1000 it would probably be worth buying. There just aren't many lower-end boards that have meter bridges. Other than the Behringer MX9000 and Mackie 8-bus, you pretty much have to move up to a full medium format console in the $3-5k+ range. Even on the digital side -- if the Yamaha 01v96 had a meter bridge option that would we great. But you have to start with the DM1000 or LS9 at $4k+ ...


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## museav (Jul 20, 2008)

jkowtko said:


> It would be awesome if Soundcraft were to offer a meter bridge for the LX7 -- even at $1000 it would probably be worth buying. There just aren't many lower-end boards that have meter bridges. Other than the Behringer MX9000 and Mackie 8-bus, you pretty much have to move up to a full medium format console in the $3-5k+ range. Even on the digital side -- if the Yamaha 01v96 had a meter bridge option that would we great. But you have to start with the DM1000 or LS9 at $4k+ ...


I have to believe that very few people purchasing an $1,800 console would be willing to spend $1,000, or anything near that, for a meter bridge so there likely is simply insufficient demand to justify it. And if an $1,800 console includes a meter bridge then think about the compromises probably required elsewhere in the console to maintain that price.


> I'm looking for something for about $2/channel, that I can solder my own wires on, etc.


I doubt that's practical. A 10 or 12 segment green/yellow/red bargraph and driver IC alone may be closer to 3 to 4 times that. Then you need a power supply, housing, scaling resistors, etc.

The direct outputs of an LX7ii are either post-fader or pre-fader but the pre-fader signal is post high pass, insert and EQ. Also, 8 of the mono inputs do not have direct outputs. I'm sure you already know this, but that would seem to limit the monitoring possible using the direct outputs.


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## jkowtko (Jul 20, 2008)

museav said:


> I have to believe that very few people purchasing an $1,800 console would be willing to spend $1,000, or anything near that, for a meter bridge so there likely is simply insufficient demand to justify it. And if an $1,800 console includes a meter bridge then think about the compromises probably required elsewhere in the console to maintain that price.


Once again I think it's marketing. The gap between the meter-bridge boards and non-meter bridge is around $2k or so ... with the exception of Behringer which sells the MX9000 for $1500 retail (and under $1k street price). The mfgs probably don't want to cannibalize on the sales of their higher end consoles by offering too many fancy features on the low end boards.


museav said:


> I doubt that's practical. A 10 or 12 segment green/yellow/red bargraph and driver IC alone may be closer to 3 to 4 times that. Then you need a power supply, housing, scaling resistors, etc.


Earlier in this thread I noted a 10-segment LED bargraph PCB unit for $2.50 ... they're not expensive. I should be able to piece together a 16 channel meter bridge by myself for well under $100 (maybe even under $50).


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## EXQEX9 (Jul 20, 2008)

So...Hows it going? Good? Good.

Oh, hey...whats a meter-bridge?

>.>


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## jkowtko (Jul 21, 2008)

I just checked the input voltage ranges of the $2.50 10-segment bargraph I mentioned above, and it looks like it will work with the standard +4dBu line output voltage (the PCB has pots to calibrate min and max signal voltage). The PCB can be powered from 5-15v, so most AC adapters will work here.

So, give me a couple weeks to get some parts and solder it up (starting with one channel) and I'll let you know ...

Either that, or I have the opportunity to buy a 32 channel Soundcraft Ghost with mute automation and full meter bridge, locally for $3k ... is that a bargain I can't pass up?


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## museav (Jul 21, 2008)

jkowtko said:


> Earlier in this thread I noted a 10-segment LED bargraph PCB unit for $2.50 ... they're not expensive. I should be able to piece together a 16 channel meter bridge by myself for well under $100 (maybe even under $50).


The linked desciption on e-BAY states the following:

> You are purchasing a Made-in-Canada Onstate Technologies multi-purpose LED bargraph meter PCB to make your own 10-segment LED meter.




> Available Model
> 
> PCB-BMBM: Bargraph Meter PCB, no parts. All electronic parts to populate the PCB are available from Digi-Key. Enclosures and connectors available from Digi-Key. Completed models with display and parts available.




> PCB designed to be used with LM3914/LM3915/LM3916


Based on this text and the picture shown, I believe what is being offered for $2.50 is simply the bare PCB board. According to the schematic you would then need 3 capacitors, 5 fixed resistors, 3 potentiometers, the LM3914 IC driver, the 10 segment bargraph, a light sensor and a switch in order to build the circuit. Also note that the intended use for that device is measuring DC voltages and the LM3914 is a linear, not logarithmic, scale.


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## waynehoskins (Jul 21, 2008)

The linear scale is probably the worst part.

For me, the four-bar idiot lights are sufficient. If I need to see something more detailed, I'll PFL it. But that's just me.


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## jkowtko (Jul 21, 2008)

Rats. Should have read it more closely ... 

So I'm going to look real hard at larger format boards with meter bridges. I'll start another post ...

Thanks. John


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