Lots of feedback with my newly installed M1 Active

[kevin_d]

Hi,

I recently purchased and installed a M1 active on my Furch Jumbo. The strapjack hole was already drilled: it took me no more than a few minutes to set up.

Problem: once I tried it on rehearsal, I plugged it onto my Vox AC30 at a very reasonable volume and I noticed a lot of feedback coming -I believe- from the condenser part of the microphone. I could hear very loudly every single move from the guitar onto my clothes (I play standing up). I have thus a few questions to whom I haven't found an answer already:

- Is there a way to reduce that feedback? Is there a best way to place the cable within the guitar (from now on, it is attached at a single point on the side of the guitar)?

- Is there a way to balance the sound between the magnetic pickup and the condenser part of it? (as does the Seymour Duncan Mag Mic I have installed in another guitar)

- If I remove the battery, does the M1 Active become a standard M1?

Thanks a lot for your answers!

[Caleb_Elling]

Hi Kevin,
The first thing that I should clarify is that the M1A doesn't actually have a microphone in it. The lower coil acts as a body sensor, but it is primarily carrying the mid-range of the guitar, and doesn't go low enough to get into the feedback range. The body sensitivity of the pickup will make handling noise much more apparent, compared to other magnetic pickups though. So that response is normal.

All pickups feedback at some point, but if you are experiencing feedback with the M1A, which it naturally very feedback resistant, then there are still things you can do to reduce it. Typically, the M1A will run into resonating feedback on the lower strings, if ever. So you may be able to adjust the pole piece height to reduce that resonance. Lowering the poles will reduce the string response slightly, in relationship to the body-sensor. Raising the poles will add more string response. So try both directions, and see what has a better effect.

An AC30 could potentially cause a lot more feedback with the M1A, compared to an acoustic amp or full PA. So unless you are going for the heavier mid-range/electric sound, you might consider trying to go into a PA (if available). You should be able to get a more natural, or at least neutral, tone that way too.

If you remove the battery in the M1A, it will not output any sound. You would need to bypass the internal preamp ion order to get sound without a battery, which cannot be done without completely re-working the pickup's insides.

There are a lot of factors that play into feedback, and there are a lot of things you can do to prevent it. If you want to go over things in more detail to work this out, I would be happy to talk with you on the phone. You can reach me at 805-929-3545 ext. 121.

[kevin_d]

Thanks a lot for your detailed answer! I have tried almost every solution you suggested, to come to the conclusion that the pickup is faulty and goes microphonic (does that make sense in english?). I'll check with my dealer for a repair/exchange/refund...

[MisterH]

Hi,

I recently purchased and installed a M1 active on my Furch Jumbo. The strapjack hole was already drilled: it took me no more than a few minutes to set up.

Problem: once I tried it on rehearsal, I plugged it onto my Vox AC30 at a very reasonable volume and I noticed a lot of feedback coming -I believe- from the condenser part of the microphone. I could hear very loudly every single move from the guitar onto my clothes (I play standing up). I have thus a few questions to whom I haven't found an answer already:

- Is there a way to reduce that feedback? Is there a best way to place the cable within the guitar (from now on, it is attached at a single point on the side of the guitar)?

- Is there a way to balance the sound between the magnetic pickup and the condenser part of it? (as does the Seymour Duncan Mag Mic I have installed in another guitar)

- If I remove the battery, does the M1 Active become a standard M1?

Thanks a lot for your answers!

Kevin,
I don't think Caleb was emphatic enough in his reply regarding the correct solution:
Simply put, you cannot use ANY typical amplifier designed for electric guitar and expect to get a decent acoustic sound. Their EQ curve is far too narrow to ever do justice to an acoustic. As you discovered you'll hear nothing but boomy midrange and loads of feedback. Run your acoustic through a PA or even purchase an acoustic amp specifically designed for that purpose. I also think you'll need to get an outboard preamp/EQ box designed for acoustics like the Para DI, for example.

[kevin_d]

The thing is, since Caleb's message, I also tested the pickup directly plugged in the P.A. and there was the same amount of feedback...

Plus I really mean to plug my acoustic guitar in a traditional amplifier: I do it already with another one without a single problem (with a Seymour Duncan Mag Mic installed), I need to switch between electric and acoustic during gigs, and I like adding effects to my acoustic guitar too.

[Caleb_Elling]

The thing is, since Caleb's message, I also tested the pickup directly plugged in the P.A. and there was the same amount of feedback...

Plus I really mean to plug my acoustic guitar in a traditional amplifier: I do it already with another one without a single problem (with a Seymour Duncan Mag Mic installed), I need to switch between electric and acoustic during gigs, and I like adding effects to my acoustic guitar too.

Have you talked with your dealer about an exchange yet? If you are encountering that level of feedback through such a wide variety of systems, then at least comparing your M1A with another one would be a really good test.

[kevin_d]

I sent it back to them, they tested it and it was indeed microphonic. Nice to know my diagnosis wasn't completely crazy! I'm getting a replacement soon.

[Caleb_Elling]

I sent it back to them, they tested it and it was indeed microphonic. Nice to know my diagnosis wasn't completely crazy! I'm getting a replacement soon.

OK,
I'm glad that you were able to get it sorted out.

All the best!