DIY - Active Monitor Controller !!!

[radiance]

What kind of subwoofer do you have? Does it have a inbuild cross over filter? For example, most subwoofers I know have a stereo input and a stereo output. The output carries the (high pass) filtered signal which goes to your speakers.
This way, all signal has to go through the sub before it goes to any of your three monitor outputs.
Here you can see a monitor/sub router I build...

For your project you will certainly need a 2 or even a 3 unit case to accomodate all the XLR chassis connectors....

 

[Purusha]

It's a huge B2092A *B* sub which I connect for now in parallel with my other monitors. It's positioned in the middle of my room just for the extra sub bass which I like to have when mixing.

http://www.behringer.com/B2092A/index.cfm?lang=ENG

 

[radiance]

I suppose your using high pass filters for you speakers then?
If you don't, you'll get some frequency overlap in the low end.
What's the frequency response of the subwoofer? and what's the frequency response of your monitors?

 

[Purusha]

Genelec

freq response is 48 Hz - 22 kHz (± 2 dB)
Lower cut-off frequency, -3 dB:< 47 Hz

Bass roll-off control operating range in 2
dB steps: from 0 to -8 dB @ 40 Hz
Bass tilt control operating range in 2 dB
steps: from 0 to -6 dB & MUTE


Sub

freq response 28 to 100Hz (-10 dB)
freq range 32 to 80Hz (+/-3 dB)

 

[ramjet]

hi

kev are you are able to post a schematic for your switcher

cheers ramjet[/quote]

 

[radiance]

[quote author="Purusha"]Genelec

freq response is 48 Hz - 22 kHz (± 2 dB)
Lower cut-off frequency, -3 dB:< 47 Hz

Bass roll-off control operating range in 2
dB steps: from 0 to -8 dB @ 40 Hz
Bass tilt control operating range in 2 dB
steps: from 0 to -6 dB & MUTE


Sub

freq response 28 to 100Hz (-10 dB)
freq range 32 to 80Hz (+/-3 dB)[/quote]

What I would want from a sub is that it (in this case) extends the bass from the Genelecs to 28Hz. If you drive both Sub and monitors without a high pass filter on your monitor signal, you will get to much bass in the 48 to 100 hz region. It might sound ok to you but it's not what you call a flat response.
Looking at the connectors on your sub I guess you should make the connections as folows:
Output from mixer > left&right input sub
left&right output sub > monitor
Your monitors should get a high pass filtered signal (@100hz) so they don't produce frequencies your sub already does.
I don't know the B*hringer sub, but most subwoofers I came across have a high pass filter on their speaker outputs.

Keep this in mind when designing your switchbox....

 

[Purusha]

Thanks, I agree with you :thumb:

I guess I'll have to change my MC idea which I had in mind. Let me sleep this over. I'll make a new basic path drawings with your idea included tomorrow. Than we can take it from there. :grin:

 

[Kev]

[quote author="ramjet"]kev are you are able to post a schematic for your switcher[/quote]
which switcher ??
the above picture is just a rotary switch .... :roll:

If you have seen the 8x1 and 16x1 switches with remote and VCA volume in OB vans etc
well they are not for DIY
sorry


Purusha
you can see that you now have many controls that need to be adjusted just to make one switch between monitors a and b

the relative nominal levels of the monitors is likely to be different and so too the x-over requirements
so even though you have used simple components, it could still get overly complicated to use

This config might suit your needs BUT others may want to have a set of monitors in the studio (for playback to the artist)
OR
a stereo feed to a master recorder
or
a feed to meters

so many options and difficult to keep every one happy

see this page for some commercial options
http://www.sweetwater.com/store/category/c417/

 

[Purusha]

I agree with you Kev :wink: there are many different needs and desires ...

As I see, I will have to make my own design to serve my specific needs. I'll start drawing a new simple drawing in a day or two and if you and other gentlemen here are still fired up to help me with some suggestions than I don't see any problem :grin:

It would be really nice if there are some usable DIY projects which could be implemented into my design like some partial designs from you and your friend Mikkel. Please let me know if you see something fitting. But first I have to narrow down my design. :thumb:

 

[Kev]

Joe will have a couple of modules very soon
the volume control unit ... PIC and PGAchip ... and the Hybrid for drive

Mikkel has the 63 step relay attenuator in a couple of configurations
and he has a relay input switcher

Mikkel's unit does require the termination to be just right ... as does any passive approach
If you do choose to go more active and put a buffer on each 63 step unit it all becomes very easy and reliable

... I will have to make my own design to serve my specific needs ...

and your needs will change
that's just the way things go
keeping thing generic but stacked with option will keep the unit alive for a long time

The Samson C-control - Control Room Matrix
http://www.samsontech.com/products/productpage.cfm?prodID=1650
very cheap and has many of the features already
use the extra speaker out to drive the sub

it's a simple start at least

 

[Purusha]

The Samson C-control - Control Room Matrix
http://www.samsontech.com/products/productpage.cfm?prodID=1650
very cheap and has many of the features already
use the extra speaker out to drive the sub

it's a simple start at least

The Big Knob from Behringer looks also nice with a lot of nice features but it doesn't sound good. This is what I am afraid off when looking at cheap gizmos like C class processor C-control.

Do you suggest that I rip out the guts from the C-control and build arround it to fit my needs? This might not be such a bad idea but I think I can build the same kinda controller for less than 99$ with relays :thumb:

I really need to open my friend's MC for 1300? and clone his design :green:

 

[Kev]

[quote author="Purusha"]The Big Knob from Behringer looks also nice with a lot of nice features but it doesn't sound good. This is what I am afraid off when looking at cheap gizmos like C class processor C-control.

Do you suggest that I rip out the guts from the C-control and build arround it to fit my needs? [/quote]
yes they are cheap
and
yes they may be less than perfect soundwise

no don't re-build it
it's $99 so use it as an experiment and open the lid to see how they went about it

use it as inspiration for your DIY project

look at page 15 of
http://www.samsontech.com/products/relatedDocs/Ccontrol_OM_4Lang_v4.pdf
it just about describes what you say you want
even with the sub woofer
substitute the kebooard for the second computer

 

[Purusha]

I just checked the price here in my country, it costs 150$, so I will most probably skip your proposition and build my own type with relays and so on.

 

[Purusha]

Forget about the C-control, as I thought it's a piece of junk, it does some wierd things above the 12KHz... :? just found out from a friend.

 

[Purusha]

I am almost done with my new monitor controller. So far everything works as planned except one thing.
I hear clicks when switching to mono. I used this circuit which was posted by NYD some time ago.
Other than the clicking mono circuit works fine.

Anyone knows how can I kill this clicking effect?

 

[ChrioN]

Just guessing here, so don't take my word for it
Try increasing the bypass caps in the powersupply for the opamps, that is if they are small like in that schematic (0.1uF). try +10uF electrolytics.

 

[Purusha]

Any other suggestions?

 

[moamps]

If you are using a rotary switch, it should be the break-before-make type.

Pozdrav,
Milan

 

[Purusha]

I am using push buttons and relays for this.

 

[tiacarrera]

hi all , im a new diy-er and i need a monitor switcher so i thought this would be a nice easy project . my needs are pretty simple , actually similar to purusha's ......

my needs are for a passive system

4 stereo inputs ( to be listened to one at a time, not together)

2 stereo outs for monitors a and b

a master volume , possibly a dim switch
a mono switch and left only/ right only switches.
and ofcourse stereo vu meters.

ive looked through the thread here and i understand the circuit for the 4 ins to a single stereo out , so i guess the stereo outs could be interupted by the volume controll first then by the a/b monitor switches . correct me if im wrong(i probably am).

also can you recomend the type of switches?? i like the rotary switch for the inputs , and outputs too i guess and then push button switches for the l/r/mono and dim

and a nice rotary encoder for the volume .
thanks, jason
austin tx.