Jump to content

New mixer idea


Tom Visser

Recommended Posts

Thinking of building myself a mixer based upon the exact features that I'd like...  feedback - good idea or just plain silly.  I have a very specific idea of how these features would be implemented, curious to see if others see things the same as I do or don't get it.

Panel dimensions would be 12" wide by slightly under 3", overall dimensions would grow a bit given the casing.  Faders are Penny and Giles 45mm throw.  Sort of a design exercise to see if a linear fader bag mixer could work or not.  Also thinking of maybe cutting it down to 4 channels instead.  Switches are NKK, rotary pots are Alps push-lock style.  The monitoring section on the right has a top row of off-on-(solo) for each of the channels and busses, and the switch below it selects left-center-right pan selection.  a Headphone 2 output provides an alternate monitoring mix, for boom op or IFB, and allows section of individual channel(s), mirror the headphone 1 mix, or a split ear of each.

web.jpg?ver=13042596670001

Link to comment
Share on other sites

This is more of an ENG bag mixer, I think 60mm would be too bulky (would add 3/4" to the overall height / depth) - maybe not, could look into it, but I can feel dimension creep already upon me.  I do have some panel idea based upon 83mm faders, but I'm quickly creating more ideas than feasible output :)  This particular design was scrapped as the person interested in me building it wanted something even smaller.

web.png?ver=13039677430001

web.png?ver=13039674140001

web.png?ver=13039674120001

web.png?ver=13039674080001

Link to comment
Share on other sites

Are you figuring that the mixer would sit in the bag with the control panels (w/faders) facing up (as w/ most bag mixers) or facing out (a la Cantar)?  What linear faders could you get that were sufficiently damped to not be easily bumped, but still move easily? 

I'm a veteran of a few mixer build projects (mostly a long tome ago)--almost all ended in tears, it's a very daunting task you've set for yourself.  I guess I wonder what you find lacking in the choices available now, and find those things so necessary that you'd go to this much trouble?  In any case, it looks like you have some very interesting ideas.

phil p

Link to comment
Share on other sites

Are you figuring that the mixer would sit in the bag with the control panels (w/faders) facing up (as w/ most bag mixers) or facing out (a la Cantar)?  What linear faders could you get that were sufficiently damped to not be easily bumped, but still move easily? 

I'm a veteran of a few mixer build projects (mostly a long tome ago)--almost all ended in tears, it's a very daunting task you've set for yourself.  I guess I wonder what you find lacking in the choices available now, and find those things so necessary that you'd go to this much trouble?  In any case, it looks like you have some very interesting ideas.

phil p

...In bag with panel facing up.  I was playing around with some 83mm version of the P&G faders, and they do move pretty easily, moderate shaking will cause them to move.  Probably a bad idea for run and gun, but could be still interesting for other applications.  I suppose a clutch of some sort could be built into the case, when engaged, moves a brush or strip against the T-handle of the fader.  A simpler solution could be in the for of some sort of foam/rubber boot that installs around / under the fader knob... or just abandon the linear fader and substitute a rotary one, although there is something about linear faders that work better in my mind for making level adjustments.

I'm working on the other housing parts, and will post renders when I have that developed further... it will in fact be slim in the bag, despite the relatively wide face.  I'm showing some close-up details of the channels and master section as my earlier master render was probably too small for people to pick out details.  That's right, a DJ-style X-Y crossfader, what would YOU use that for, or would you find it completely useless?  It was in part inspired by the recent debate on mono versus boom / lav split discussion on here recently.

I think there are a lot of contemporary mixers that are outstanding and meet most of my needs.  Some people like to design websites in their spare time, my creative outlet is in the form of designing things like this.  With online machining and PCB manufacturing becoming even more approachable for rapid development and small production runs, DIY opportunities are also within the realm of saneness, making projects like these more feasible than they probably were in the past.

web.jpg?ver=13042801930001

web.jpg?ver=13042802030001

Link to comment
Share on other sites

Must say that I like the challenge you undertaken... If you implement brickwall limiter "type SD302" and cooper design preamps I will be interested in one! :) Direct outs?

//Christian

Here is an image of the housing.  The top panel fits in the wide section, there is enough depth there to fit the P&G fader plus some very small PCBs for the electronics.  The top panel would be recessed, so from the side profile controls would not be sticking out.  The slim side section is wide enough to fit full size XLRs.  I figure on the left would be 6 XLR-3F for the mic/line inputs and on the wide top side, a DB-25 for 6 direct outputs plus the LR mix.  On the right, would be 1 XLR-4M for 12VDC power, 2 XLR-3M for LR output, a mini-jack for tape return, mini-jack stereo tape out, 2 TA3 balanced tape output, TA5 for monitor1 line output (or 2 TA3?), TA5 for monitor2 line output (or 2 TA3?) , and 2 1/4" TRS for headphones 1 and 2.  Did I miss anything?  There will also be space in the slim body between the connectors for additional electronics or battery compartment.  How important is on-board batteries?  There is no way with my resources that this thing would be very power efficient.  I'm thinking a 10x AA battery sled would likely be out of the question.  D cells or an NP-1 would be the minimum AH requirement.  Do limiters need to be on each channel or can I get away with a single set of limiters on the LR mix buss, linkable if need be, but I don't really think of this as a "stereo mixer" per se, more of a dual mono mixer, otherwise variable pans and such would be required... but that is for another even more ambitious day.

web.jpg?ver=13042829310001

Link to comment
Share on other sites

Hi Tom,

The led holes look like they would make the panel very weak as there is not much metal between them and they run the length of the entire panel. If punched out the metal inbetween the holes might twist as well.

Glenn

Link to comment
Share on other sites

hi tom,

i m also impressed by this challenging task that you re undertaking,  i like the idea of sliding faders for bag type mixer. and the crossfade monitoring could simply be a rotary switch for saving space

seconding christian for quality pre-amps and limiters (hi christian! remember me?).

and finally on the electric tip, i really like the powering flexibility of my current mixer (psc alphamix) it can run on internal np-1 batt or from ext 12v power and can also redistribute up to 4 x 12v running devices like lectro recievers and a recorder... all from 1 battery.

fascinating stuff, keep us posted on your devellopements,

Dominique

Link to comment
Share on other sites

Thanks Glenn.  Maybe the answer is simply to place a gap for the row of LEDs?  I was using 0.1" spaced LEDs as a reference for placement.  I could also drop down to 9 segment meter, but that seems a bit granular.  I guess with the larger main meter for solo metering it could be ok.  Ah, the advantages of LCD / touchscreen designs... 

Dom, the crossfade is actually not for monitoring, but for the mix buss.  In the recent discussion about boom / lav split - dual mono mixes, it occurred to me that in instances where one needs to pan mic(s) for the lav mono mix, one could "cue" the upcoming fader move on the "y" buss, then cross to y, then prepare next move on "x" and fade to x...  All the while being able to monitor x or y without making destructive mix moves, also making fades with graduated crossfade of multiple mix simultaneously with a single control / motion.  In the classic closeup / reverse situation or maybe reality where cutting in and out of the main subject and then to the "group".    Not to mention the massive tracks the sound crew could lay down for the after party...

Link to comment
Share on other sites

Changed the LED holes to 1mm to accommodate LED lightpipes rather than for the device itself, which was 2mm diameter.  Should be enough to maintain front panel integrity?

I also updated the master/monitor section.  added a limiter with 2 segment feedback.  (hey that was easy)  Now to tackle the electronics side of things.  The chassis is as small as possible given the components and full size connectors specified, but the challenge is to see if I can make things fit, otherwise I will have to gradually grow the enclosure - am trying to stay away from surface mount if possible, but I guess if that is the only way it will work...

web.jpg?ver=13043686890001

web.jpg?ver=13043717300001

Link to comment
Share on other sites

Are the buttons in the master section the pfl's for each channel?

I like your design and the fact that its 6 channel.

I think you could do away with the pre/post metering option. I like the channel mute tho! I'd like to see the pfl at the channel strip,maybe integrate it into a toggle like the 442?

Will the PAD and lc  be variable?

Also, why not go with mini xlr for the inputs?its not that big of a deal to switch and it would savetones of spaces and weight.I do understand the need for full size xlr but I would just make a pigtail. :-)

Dig your design!! Look forward to seeing where this goes!

Link to comment
Share on other sites

Here is an image of the housing.  The top panel fits in the wide section, there is enough depth there to fit the P&G fader plus some very small PCBs for the electronics.  The top panel would be recessed, so from the side profile controls would not be sticking out.  The slim side section is wide enough to fit full size XLRs.  I figure on the left would be 6 XLR-3F for the mic/line inputs and on the wide top side, a DB-25 for 6 direct outputs plus the LR mix.  On the right, would be 1 XLR-4M for 12VDC power, 2 XLR-3M for LR output, a mini-jack for tape return, mini-jack stereo tape out, 2 TA3 balanced tape output, TA5 for monitor1 line output (or 2 TA3?), TA5 for monitor2 line output (or 2 TA3?) , and 2 1/4" TRS for headphones 1 and 2.  Did I miss anything?  There will also be space in the slim body between the connectors for additional electronics or battery compartment.  How important is on-board batteries?  There is no way with my resources that this thing would be very power efficient.  I'm thinking a 10x AA battery sled would likely be out of the question.  D cells or an NP-1 would be the minimum AH requirement.  Do limiters need to be on each channel or can I get away with a single set of limiters on the LR mix buss, linkable if need be, but I don't really think of this as a "stereo mixer" per se, more of a dual mono mixer, otherwise variable pans and such would be required... but that is for another even more ambitious day.

web.jpg?ver=13042829310001

I would put the inputs on the underside of the upper section.  Like the Nomad or the Sonosax recorder.  I do almost only bag work and I rarely have to unplug anything as I leave my kit built in my petrol bag.  Maybe a compromise of having 2 inputs on the side and 4 underneath.  Obviously outputs to the sides. 

Any thoughts of a digital I/O? 

I like the idea of sliding faders for the field or knobs, quicker and easier control for sure. 

Good luck.

J Hemmerlin

Link to comment
Share on other sites

Are the buttons in the master section the pfl's for each channel?

I like your design and the fact that its 6 channel.

I think you could do away with the pre/post metering option. I like the channel mute tho! I'd like to see the pfl at the channel strip,maybe integrate it into a toggle like the 442?

Will the PAD and lc  be variable?

Also, why not go with mini xlr for the inputs?its not that big of a deal to switch and it would savetones of spaces and weight.I do understand the need for full size xlr but I would just make a pigtail. :-)

Dig your design!! Look forward to seeing where this goes!

As I started to dig into the electronics portion of the design - well... some things had to go.  I already eliminated the pre/post options for the meter and direct outputs (direct is still there on DB-25, just the per/post option is gone).  I'm also going to move a lot of the switches to the side panel, just leaving things that would logically need to be changed on the fly on the front panel - 80Hz filter, mute, and buss assignments.  Mic/Line and phantom switches would be near the XLR jacks, which also happens to be where the preamp electronics will be, so will eliminate the need to route cabling internally to and from the front panel.  I thought to myself, when is the last time I actually used the PAD in a normal production environment?  I did once on a video shoot where I was using DPA boundary mics on a jazz drum kit.  I carry around in-line barrel pads, so do I really ned to include it on the mixer?  I'm either going to use a separate balanced line receiver switchable to the preamp for mic/line selection or possibly just use a resistive network in front of the preamp, in which case I might be able to keep the PAD, as it would basically be "free" utilizing parts of the circuit that would be there already - but it is on the chopping block.  If it does stay, will likely not be variable.  The LC will be fixed, and on my current version, is fixed at 80Hz.  Thinking about it, will probably revert it back to 80Hz and 120Hz selectable, as that is not a lot of work or space required.

The monitoring section works pretty much just like the monitoring section of my Nagra VI (go figure).  I really like that arrangement. I've grown used to making the monitoring routing choices at the master section rather than the channel strip (especially as the VI doesn't really have one).  I know this departs from the standard from large panel mixers, but I personally think having them all located at the master section makes sense as your fingers don't have to do a lot of moving around.  The NKK switches are 3 position with the 3rd down position momentary.  Up means monitoring of channel is off.  Middle is monitoring enabled.  Down momentary push solo's the channel (pre-fade).  There is a LCR pan assignment (just for monitoring) immediately below.  So if you want to listen to the LR mix buss in stereo, you would only enable the L and R channels, and then for proper stereo monitoring, pan L to the left and R to the right.  More typically, I would boom on L buss and mix lavs on the R buss.  I've never been a big fan of split ear monitoring, too confusing for me, so would likely monitor L and R both in mono, also good for detecting phase issues.

Here is where the mixer gets a little unique...  Say you have a boom, fine, put that on the L buss.  Say there is a reality situation where you have the primary talent, talking to a group of 3, each wired up.  With this mixer, the concept is that you could put your primary talent on the X buss and the group on Y.  The challenge with a 2-mix, 4 people, and 5 mics, is how do you do that with just two hands?  The experts here already have that figured out, and hopefully this would let me do my job better, and in the best case scenario, the experts would find this product helpful too.  In many situations, I do my own booming, so really have to do it with 1 hand.  So we have boom on L, primary on X, and group on Y.  The crossfader would be assigned to R, could set my levels, mute individuals as needed (they leave the area), pre-fade listen to specific mics to find problems and make adjustments, have good metering for all inputs, etc... and once everything is reasonably set, with one hand I should be able to crossfade between the primary and the group, while still maintaining the boom position and my right hand reaches down to make the crossfade.  I can solo the Y buss before I make the fade to listen to quality of audio of the "Y submix", just like a DJ would while cueing up music.  If you don't want to entirely cut out the primary, just fade to the middle position rather than to the extreme X-Y positions.  I guess I would have to work on the log curves a bit to make the sound power primarily fall off at the extremes of the fader position.

I have to put my design work on hold for a couple of days as I get busy, and probably have to put another project for a paying customer at the head of the line, but this has been where most of my in-between-clock-cycle energy has been spent recently.  I don't know why I enjoy things that are so frustrating.

As far as mini-connectors, will use them for things like tape sends, but personally refuse to have anything but full-size XLR connectors for inputs and main outputs.  This project is really for me, not for the general public, and something that I won't easily bend on.  The "depth" or "length" of the mixer is under 8" which is compact enough for my purposes.

Link to comment
Share on other sites

I would put the inputs on the underside of the upper section.  Like the Nomad or the Sonosax recorder.  I do almost only bag work and I rarely have to unplug anything as I leave my kit built in my petrol bag.  Maybe a compromise of having 2 inputs on the side and 4 underneath.  Obviously outputs to the sides. 

Any thoughts of a digital I/O? 

I like the idea of sliding faders for the field or knobs, quicker and easier control for sure. 

Good luck.

J Hemmerlin

I thought about that.  The P&G 3000 series faders are pretty deep.  They would almost touch the bottom of that housing as pictured. If I put XLR connectors there, they would of course have to be staggered with the faders - not a big deal, but also that is one of the primary places where PCB boards would be installed.  Doing so might have to make that section bigger.  Having cables come down there would also take up a lot of that empty space.  Most bags have side-exits for cabling, so the original configuration seems to make more sense to me.  I do like the concept of the cables coming down into the recessed area, but worry about making the case bigger and reducing the "slimmness" of the profile.  Right now, one could put a fairly large box, like battery packs, or even a wireless "pak" or distribution system in there.

With respect to digital I/O, I would love to add it, but it is a completely separate function from the core mixer itself, and will investigate that later down the road.  I have some queries out to people who make integrated chips, like TC Applied for the possibility of something like Firewire connection, but at this point, digital I/O would be a luxury that I won't distract myself with at the moment.  At the very least, I would like 4 channels of AES output with WC, 8 would be better.  Can definitely say that if it does happen, connectors will be DB-25 and BNC - no space for anything else.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...