Xtalk between Bass and Snare Rim

[marcddsa]

Hi there

On my Dmitri built 32 input unit I get annoying xtalk between my bass and my snare. Both are mechanically isolated from each other (bass is standalone and snare is on a snare stand.)

Both drums are homebuilt cone piezo units in acoustic shells with mesh heads with the snare rim piezo mounted on double sided take in the shell. The bass has a 27mm piezo.

Xtalk happens on the snare rim sometimes after even 1 hit on the bass. HighLevel on the bass is around 800 with or without a 10k resistor on the tip lead. (both indicate that the the bass pad should not be hot)

Both scenarios give xtalk on the snare rim.

Any idea what could be causing the xtalk? I've tried setting both sensor levels to 7 with the same issue. When I disable the rim piezo the xtalk obviously goes away.

Do I need to go with a bigger resistor?

Thanks in advance.
Cheers

Marc

[airflamesred]

What are the thresholds?

[marcddsa]

Ah ha.... Got me thinking .......

The snare (head and rim)is on 35 and the kick is/was on 40.

Checking the midi log again, this even manifests itself with a light hit on the kick.....

But.... I played with the threshold on the rim... At 55 the Xtalk goes away..

Is 55 still good? Rim shots still sound good...

[ignotus]

If it works, it works. To me at least, those seem like high threshold values, which would indicate very sensitive or 'hot' piezos. Nothing wrong with that per se, as long as the high level doesn't max out too easily.
If the x-talk problem with the rim has gone away and it still picks up fairly light taps, I wouldn't worry. However, if you had to raise threshold to a point where it is insensitive to lighter hits, there might be something else going on.

[marcddsa]

You guys rock.... Thanks for the input...

I'm going to cool down the pads at bit more tomorrow (my 4 toms are of the same construction) and carry on testing to see if I can get the thresholds down but the direction given was awesome.

I'm going to my local electronics shop tomorrow to get some pots and stripboard and will just add voltage dividers to each of the homemade pads instead of adding resistors... Will update the post with some more info when I get it.. Maybe some other newbies will be able to learn from it.

[ignotus]

I wouldn't worry about the thresholds too much - as long as the pads pick up light hits and trigger rolls properly, but don't have x-talk problems they're fine. Pots or resistors would be called for if your auto high levels peak at over 900 too easily.

That said, I have trimpots on every input. Even if the pads don't seem to be too hot, I've found with some pads that the dynamics improve with a carefully adjusted trimpot; sometimes there isn't a gradual transition from mid to high velocities, it just leaps from one to another, and the trimpots fix that really nicely. It hasn't happened on all pads so I suppose it's to do with their DIY construction, but I find them essential. I use 10k trimpots, FWIW.

[dmitri]

On my Dmitri built 32 input unit I get annoying xtalk between my bass and my snare

Before raising Thresholds I'd recommend to put both inputs in the same XTalk Group and raise XTalk Level on both of them.

[marcddsa]

Hi Dmitri

Thanks for the reply. I tried that first with no luck but I'll try again tomorrow after I set up the trim pots...

Cheers

[dmitri]

Are you sure that the xtalk from the Bass is actually to the snare rim? Maybe you have some other(s) unused input(s) with the same note number as the snare rim?