Audio Technica PRO 70 Problem

jmayojscc · February 2009

Man, was I happy to find this mic (and this forum!). I play bluegrass and folk, and the guitar I use most of the time has a great sound but isn't loud enough to compete with other instruments. I was getting tired of moving back and forth into mics!

So far, I've used the Pro 70 only twice. The first time, it was great. I loved it. No problems. Great sound. Throughout the show, I experimented with different placements of the mic until I found one that suited me.

The second time I used it, I had trouble. We kept getting this loud roaring low end feedback. We couldn't figure out what the problem was. I even kept accusing our bass player of causing the trouble. I kept saying "Mute your strings!" Of course, I was the problem. Something in the Pro 70 wasn't working.

I could mute my strings and turn the power pack on and we would get that low roar. I took the battery out and used straight phantom power. Same problem. I switched cords. Same problem.

The only time it wouldn't roar was when I was playing. After a song, roar. Turn on the switch, roar.

Any ideas?

Adelaarvaren · February 2009

Forgive me if this is too obvious! There is a low frequency cut on the belt connector. DId you have that engaged?

jmayojscc · February 2009

No, I hadn't noticed that. Like I said, I yanked it out of the box, used it a couple of weeks ago, and then used it again Tuesday. I hadn't noticed. I'll check it out when I get home, though.

Thanks!

Caravan GSE · February 2009

I have been using this mic off and on and really like it. The low end switch is most likely the problem. It definitely makes a difference. I feel like when playing rhythm guitar it is kind of noisy sometimes. Any thought?

jmayojscc · February 2009

I just got home from work, dug the PRO 70 out the case, and looked it over. The only switch I have is the switch on the side that I used to turn it off and on.

There are two options when switching it on. The switch has these three symbols (or something close) in this order top to bottom:

/---
___

Off

That top symbol is sort of hard to pull off when typing, but you can probably get the idea.

According to the paperwork, these are for off (obviously), on-flat, and on-roll-off. Is this the switch you mean? And it didn't really matter which position the switch was in---we got the same roar either way, as soon as I flipped the switch.

I sort of feel like a fish out of water these days. I played for many years but sold all my gear years ago when I left Nashville for grad school. Now that I've gotten back into years later, it seems like I've been asleep for 20 years!! I promise, I used to know more about this!

Thanks for your help, by the way.

marciero · February 2009

Yes- the symbols are supposed to be frequency response curves. The flat one is... flat. It's the top one that rolls off bass.

jmayojscc · February 2009

so I'm learning!

So any thoughts about what the booming might have been? It seems to me that not matter which position the switch was in, we had building shaking roar. I'm just wondering if maybe the switch is bad.

James

Caravan GSE · February 2009

I would tend to wonder if maybe there is a problem with the mic.

One other thing of note is that both John Jorgenson and Kevin Nolan are using the Pro 70. They are rigging it up below the strings and behind the bridge with a home made bracket. That gets it away from the sound hole witch can be problematic. Kevin showed it to me last time they were here. They have the mic taped to a cut up hotel key card and woven through the strings behind the bridge. It is pretty funny but it works for them. I have not tried that yet.

I use the provided lapel bracket and extend it as far away as possible from the sound hole. I actually think that I took it apart and reversed the bracket to get it further away from the sound hole but still hooked on it. I will have to look at it again tonight.

It's a nice mic. Pretty hot signal!!

V-dub · March 2009

I have a Pro 70 as well and I have had trouble using it in live situations. Same problem: boomy low end feedback when mounted to the sound hole. I can't really use it at any audible volume without the feedback. Usually I just give up on it and go back to the big tone.

Definitely interesting to hear about the Jorgenson setup. Can you describe it in a bit more detail? Which direction does the mic point in? Is it towards the bridge?

BluesBop Harry · March 2009

V-dub wrote:

I have a Pro 70 as well and I have had trouble using it in live situations. Same problem: boomy low end feedback when mounted to the sound hole. I can't really use it at any audible volume without the feedback. Usually I just give up on it and go back to the big tone.

Exactly the same for me and it's not as meaty as the BT.
Great for recording and going straight to a PA with a sound engineer, sucks through an amp.