Author Topic: Oh for the love of God can someone help me out with this??! (Read 5168 times)

dunebug81 · « **on:** April 15, 2005, 05:47:48 AM »

For the past...oh I dunno year or so something wacky has been going on with my mics and the only 2 solutions to fixing my recordings are A: record in mono or b: copy one channel to the other channel (in soundforge) to equalize the l and r channels. Well Ive got a new HIMD recorder and since there is no mono setting and Id really rather record in stereo anyway I need some help with finding out what is going on.

Thats pretty much what all stereo recordings look like. Originally I was told that my battery in my battery box was low but I used a freshly recharged 170 mAh 9v and its still like that. Now heres the part that I really dont get. This 1st image is the 1st band...the 2nd image is the last band to play...

Why is the one channel all out of wack for the first band but then during the 2nd it creep up to being with in 2-3db of the other channel?

Im totally and utterly confused by why this is the way it is....please help me out of you can!

-Greg

hexyjones · « **Reply #1 on:** April 15, 2005, 07:00:45 AM »

Bad capacitor...somewhere...?

neutrino · « **Reply #2 on:** April 15, 2005, 07:13:22 AM »

What's the make/model of the mics you are using? Are you using a battery box?
dB-

dunebug81 · « **Reply #3 on:** April 15, 2005, 07:25:39 AM »

Ya, sorry...I ment to put that in the original post.

CSBs > battery box (bass filter off) > HIMD

-Greg

Wedge · « **Reply #4 on:** April 15, 2005, 07:56:29 AM »

I've got CSBs, but can't remember - is it possible for you to plug the CSBs directly into the mic-in - that is, without using the battery box?

You could at least isolate where the problem is - if you get a good (i.e. balanced stereo) recording going CSBs>HiMD(mic-in) then the problem would appear to be with the bbox.

If, however, you get the same results going mic-in, then it looks like one of your mic elements may be damaged?

Hope this helps.

In general, that is the way I approach problems like this - isolate the elements in the chain to find the fault.

Teen Age Riot · « **Reply #5 on:** April 15, 2005, 11:44:16 AM »

Hmm, maybe the battery inside the box is loose and therefore connects and disconnects all the time? I've had that once and I totally freaked out until I saw what was wrong.

I'd say connect everything, put the MD into rec/pause, and plug your headphones in. Listen if it sounds weird (or if the sound changes) when you shake the battery box. Touch, shake, etc. other parts of the rig as well (especially connectors) and see if you can hear what causes the problem.

dunebug81 · « **Reply #6 on:** April 15, 2005, 02:52:05 PM »

Mics wont go if they arent plugged into the battery box so i cant test your theory.

I put in a new battery every other show and if it was disconnecting then the sound would cut out and not just be lower in one channel.

Oh how i need the cash for some new mics before NIN and music midtown.

-Greg

dklein · « **Reply #7 on:** April 15, 2005, 08:52:31 PM »

could you post a clip or tell us what it sounds like? Is it clean but low level? I noticed some full scale points on there - are they crackley sounds?

Maybe one mic isn't receiving bias voltage?

dunebug81 · « **Reply #8 on:** April 15, 2005, 09:14:21 PM »

Sure... www.enemyzero.com/greg/tunes/dead60s.mp3

It sounds fine its just way lower then the other side. As for the spikes thats some sort of loose connection somewhere and usually its only one or two per set and they are easy enough to fix. i went and had the 9v tested today and it tested perfectly. Unfortunatly I cant find a place to look at the box itself. I guess it would just be worth it to buy a new box but I dont really want to sink any money into it because id like an all new set up.

-Greg

dklein · « **Reply #9 on:** April 16, 2005, 12:23:37 AM »

Do you have a multimeter or something that can read voltage? Even a little LED or flash light bulb. The yellow circles are the pins that give the left/right bias voltage. It's ground + one of the yellows for each channel. For ground, you can just touch the switch or the rim of the connector - no need to jam two probes in the little connector.. If you're using a meter, you'll notice that the box is actually set up as ground positive and each pin carries the negative (red end to the switch/rim, black end to the mini-xlr pin.

Anyways...make sure you can read voltage off both of those...I'm thinking only one may be working.

poorlyconditioned · « **Reply #10 on:** April 16, 2005, 01:48:08 AM »

Quote from: dklein on April 16, 2005, 12:23:37 AM

Do you have a multimeter or something that can read voltage? Even a little LED or flash light bulb. The yellow circles are the pins that give the left/right bias voltage. It's ground + one of the yellows for each channel. For ground, you can just touch the switch or the rim of the connector - no need to jam two probes in the little connector.. If you're using a meter, you'll notice that the box is actually set up as ground positive and each pin carries the negative (red end to the switch/rim, black end to the mini-xlr pin.

Anyways...make sure you can read voltage off both of those...I'm thinking only one may be working.

Dear David,

Does that mean the CSB use the "Linkwitz mod" for powering? I've suspected this, but didn't know for sure.

Also, can you please give me the pinout for L and R? Ie., what are the numbers on the MiniXLR plug. I'd like to use the same convention on my battery boxes.

Richard

dklein · « **Reply #11 on:** April 18, 2005, 10:46:36 AM »

Richard - I'm not sure but I suspect that they use the 'lazy mans linkwitz mod' that was discussed in our favorite DIY group. By reversing the polarity of the bias voltage, the FET goes into source follower. If I recall correctly, this only worked with the old capsules that aren't available anymore (the WM-60). I think the 61s need the hack job.

As far as the pin outs go:
1 left bias (-)
2 right bias (-)
3 tip (right output)
4 ring (left output)
and as I mentioned, the whole thing is ground +'ve.

Because the whole thing is 'reverse powered' the wiring convention is not something to copy unless you're using unmodded WM-60s. Otherwise, you'll be reverse biasing the mics. And as far as left/right goes...well, you can just label that after the fact!

I guess this also means that CSBs are out of absolute phase.

poorlyconditioned · « **Reply #12 on:** April 18, 2005, 04:01:01 PM »

Quote from: dklein on April 18, 2005, 10:46:36 AM

Richard - I'm not sure but I suspect that they use the 'lazy mans linkwitz mod' that was discussed in our favorite DIY group. By reversing the polarity of the bias voltage, the FET goes into source follower. If I recall correctly, this only worked with the old capsules that aren't available anymore (the WM-60). I think the 61s need the hack job.

As far as the pin outs go:
1 left bias (-)
2 right bias (-)
3 tip (right output)
4 ring (left output)
and as I mentioned, the whole thing is ground +'ve.

Because the whole thing is 'reverse powered' the wiring convention is not something to copy unless you're using unmodded WM-60s. Otherwise, you'll be reverse biasing the mics. And as far as left/right goes...well, you can just label that after the fact!

I guess this also means that CSBs are out of absolute phase.

OK, I get it now. This is called the "2 wire Linkwitz mod". (If anyone is interested, visit the Yahoo group, micbuilders for details.) Anyway, both WM60 and WM61A are the same. You need to perform minor surgery on both capsules for this. Nothing serious, but you need a steady hand and maybe some bandaids in case you slip with the exacto knife

.

Richard

dunebug81 · « **Reply #13 on:** April 18, 2005, 06:02:31 PM »

OK, so get this. Last night I go to mudvayne and tape both openers with the filter off and the levels are about 16db different...however I turn it the filter on for mudvayne and to start off with the L is about 5-7 db lower and after about 15-20 min of recording both channels are with in 1-2db of each other. Its very odd. I think Ill just spring for a new battery box and hopefully that will fix these issues.

Thanks for all your help guys.

-Greg

dklein · « **Reply #14 on:** April 19, 2005, 09:40:10 AM »

If you're done with it, I'll take your old one for a little dissection. I am very curious what could cause this

dunebug81 · « **Reply #15 on:** April 19, 2005, 02:44:20 PM »

Alright, ill let you know.

-Greg

mhibbs · « **Reply #16 on:** April 21, 2005, 05:41:16 PM »

Have you flipped the mics to see if it follows the mic or if it is somewhere further down the chain?

dklein · « **Reply #17 on:** April 22, 2005, 01:04:13 AM »

Quote from: mhibbs on April 21, 2005, 05:41:16 PM

Have you flipped the mics to see if it follows the mic or if it is somewhere further down the chain?

you can't flip the mics - these use a 4 pin connector (see the pic earlier in the thread)

dunebug81 · « **Reply #18 on:** April 26, 2005, 02:44:32 AM »

Well on my travels to Charlotte this week I got ahold of a friends CSB box and the L is way lower then the R so since the box is working OK Its gotta be the mics themselves.

I picked up a pair of DPA 4060s that are just fantastic! However Id still like to get the mics fixed...anyone have any idea how much it would cost? They were only $250...would it even be worth it?

-Greg

jbraveman · « **Reply #19 on:** April 27, 2005, 10:44:57 AM »

I would call Len and ask about repair. Mine died after about 10 years and it was a great excuse to upgrade.

dunebug81 · « **Reply #20 on:** April 27, 2005, 01:48:58 PM »

Ya, I guess it cant hurt to call huh?

-Greg

dklein · « **Reply #21 on:** April 27, 2005, 07:03:01 PM »

keep in mind they were made with Panasonic WM-60 capsules which cost ~$2 each... But they have been discontinued so you either find someone with stock (prolly Len) or replace both capsules with the WM-61, which are a little more sensitive.

Another possibility is that you have a connector issue and the capsules are ok. Dissection time!

Author Topic: Oh for the love of God can someone help me out with this??! (Read 5168 times)

hexyjones