Quantcast

Sound only coming out part of speaker

mjtaylor

Novice Member
Hi,

I have a pair of Edirol (now Cakewalk) MA-15D Monitor's hooked up to my iMac. The Left monitor is only outputting sound from the small top part of the speaker.

Any ideas what I can try?

I've tried using a digital input rather than analogue with no effect. When I attach my headphones to the monitor they do out put in Stereo.

Faulty speaker? Appreciate your help, thanks.
 

MaturityDodger

Well-known Member
Yes, it sounds like a faulty speaker to me.

It's quite likely that the LF driver itself has blown. Failing that, a connection inside could have come loose, or a component in the crossover. (I won't say a problem with the amplifier, because from looking at the spec, I think the speaker might share one amp between the HF and LF?)

Are you still in warranty for the speakers? Otherwise, how do you feel about opening it up and having a poke around?
 

mjtaylor

Novice Member
Thanks for the knowledgable reply. Yep, they share a built in amp on the right monitor.

Out of warranty. Happy to have a poke around, better try that before I replace them!
 

MaturityDodger

Well-known Member
Just because all the amplification is located in the right speaker, doesn't necessarily mean that the HF and LF share the same circuitry!

And if the amp is in the right speaker and it's your left one that's not working properly, that does open up a couple more possibilities as to what the problem is.
What is the connector like between the two speakers? How many cores?

Do you have access to a multimeter?
 
Last edited:

mjtaylor

Novice Member
I have a basic rapitest DM10 mulitmeter.

The connection between the two is an RCA Phono to RCA Phono cable.
 

MaturityDodger

Well-known Member
Wow. Didn't know it was safe to send high-level audio over RCA! If there's just one RCA then it must be amplifying HF and LF together.

But anyway... First see if you can unscrew anything on the right speaker to open it up.
No, scratch that. First unplug the speaker and then open it up as above!

Have a look and see if you can see and joints that have come loose.

The architecture of your speakers will probably be:

Input connectors -> a module containing DACs and amplifiers for both channels together (and the front-panel controls)

Then this module will output to a crossover for the Right speaker, and then the Right drivers. It will have another output that goes to the connector to the Left speaker. The crossover for the left speaker will be in the left speaker itself. See if you can identify all of these components.

Open the Left speaker too and check the crossover is there.
 

MaturityDodger

Well-known Member
No problem.
My next advice if my above assumptions are correct is going to be to power them up, and play some music through them quietly.

Only power them up if you are confident that you're safe. You will be dealing with live electronics.
There are guidelines to follow when dealing with live electronics. I'm not going to tell you any of them because I'd really hate to do half a job of teaching you if you don't know it already.

Set your multimeter to its lowest AC voltage setting, and see if there's anything at the output of the left crossover (input to the left LF driver). Check that it's similar to that in the same position on the right speaker.
 

mjtaylor

Novice Member
Ok. There is a lot more circuits in the Right (powered) speaker than I expected! Thinking this may be beyond me, I'm afraid. Left is very simple and the connection looks fine. Everything I move in the right, appears to unplug another wire! I can install a light switch circuit, but this is a bit too fiddly.

Really appreciate your help and advice. Looks like I might need to investigate buying a new pair.
 

MaturityDodger

Well-known Member
Ah, that's a shame. I was expecting a lot in the right speaker (after all there is DAC, control circuitry, 2 channels of amplification and a crossover), but I was hoping that it might be pretty well modularised and so easier to diagnose.
 

mjtaylor

Novice Member
I was expecting lots in there, but, as I slowly removed the back the 3 layered boards fell on top of each other and about 5 plugs came loose! 2 of the boards are connected to the front of the speaker, which I had difficulty unplugging so was left with very little access. A bit gutted!
 
Top Bottom