Bose L1 model II feedback issue: update

[Bob-I]

i work with an acoustic duo, acoustic guitar and electric bass. My partner, the bass player, has a Bose L1 model II with a B2 bass module and ToneMatch mixer. We run both mics, amplified acoustic guitar and bass all into this system. We've done maybe 8-10 gigs with this system and it always works well with very little problems.

Last night we played at a new venue for us, a small bar. We had a fairly small space, maybe 10'x8' space and about 6' from the bar. We set the Bose against the wall, mics about 4-5' in front of the system about 6' apart. I know Bose recommends at least 7' away from the system but we often don't have that much space and it works fine.

Typically we run the system up to about the mid point or up to 20% above on all controls after setting the gains and it fills rooms with no feedback. Last night we were only able to run the system at maybe 40% on the master and we had terrible feedback trouble.

We turned the mics away from the tower about 20 degrees but still we had occasional squeals.

I plan to use the parametric EQ to find the frequency and tune it out, but I'm hoping that there are other, simpler ways to prevent feedback, after all that's Bose's big marketing campaign. The problem with using the PEQ is time. Often we only get 10 minutes to setup and the Bose allows us to get going in no time at all.

Any suggestions?

[jseth]

Bob-I;

I'd go to the Bose User's Forum; it's a GREAT resource where all the moderators actually are Bose Techs! Lots of info on all their systems, from people who use them...

Doesn't Bose say NOT to put the L1 against a wall? I think they do... even a couple feet is better than nothing... next, you need to remember that the Bose is not like conventional PAs... and make use of the amazing dispersion that they have... I have to constantly remind myself that I don't need to have the tower behind me, or close-ish to me... since the dispersion (horizontal) is dead-on at 180 degrees, all you need to do is to be part of that wide sweep.

Try positioning the Bose where it covers the room, but is not right on top of you. I can't imagine having feedback trouble with mine; I use a Shure Beta-58A, and have never had even a whisper of trouble with it... and I've had to play places where things were too cramped to be the recommended distance away from it, too...

You didn't say what, exactly was feeding back? Do you have any clue as to the approximate frequency range that's the problem?

First off, take all the effects OUT of the output; reverbs and delays can wreak havoc with signal, even though it's the same level you've always used... moving the bass bin, even 6 inches off axis, can tame runaway low end feedback; I also ALWAYS have the bass bin on the "neck" side of my guitar, not on the "body" side...

Hope some of this helps...

[MaurysMusic]

Originally Posted by Bob-I

i work with an acoustic duo, acoustic guitar and electric bass. My partner, the bass player, has a Bose L1 model II with a B2 bass module and ToneMatch mixer. We run both mics, amplified acoustic guitar and bass all into this system. We've done maybe 8-10 gigs with this system and it always works well with very little problems.

Last night we played at a new venue for us, a small bar. We had a fairly small space, maybe 10'x8' space and about 6' from the bar. We set the Bose against the wall, mics about 4-5' in front of the system about 6' apart. I know Bose recommends at least 7' away from the system but we often don't have that much space and it works fine.

Typically we run the system up to about the mid point or up to 20% above on all controls after setting the gains and it fills rooms with no feedback. Last night we were only able to run the system at maybe 40% on the master and we had terrible feedback trouble.

We turned the mics away from the tower about 20 degrees but still we had occasional squeals.

I plan to use the parametric EQ to find the frequency and tune it out, but I'm hoping that there are other, simpler ways to prevent feedback, after all that's Bose's big marketing campaign. The problem with using the PEQ is time. Often we only get 10 minutes to setup and the Bose allows us to get going in no time at all.

Any suggestions?

These 2 words will save your Bose-using life. Noise gate.

It took me a few years to discover it, but once you use the T1's noise gate, feedback rejection is GRRRREATLY improved. In my acoustic duo, we set both our mic channels to gate with a threshold of approx -35db and speed to 100. Best way to select the threshold that works for you is to sing right up on the mic, and set it so that singing opens the gate, and loud talking does too (between song banter with the crowd) but quiet talking won't open it. WE do NOT gate the guitars. Best of luck.

[Bob-I]

Thx for the replies. I did go to the Bose forum and read a bit there.

The feedback is very HF, maybe 8K and does not stop when we block the mics with our faces. We'll try moving it away from the wall, jseth makes a good point, we will hear ourselves no matter where the tower is.

We did have LF feedback from my Taylor 214CE (stock PU+quackbuster) but that was resolved with a soundhole cover.

We will turn on the noise gate, I can see how it may help.

[MaurysMusic]

I forgot to mention that vocal feedback is greatly reduced if your mics are aimed at a 45 degree angle towards the ceiling, as opposed to a 90 degree angle straight at your face. That helps a lot and the Bose forum turned me on to that tip.

[Bob-I]

Originally Posted by MaurysMusic

I forgot to mention that vocal feedback is greatly reduced if your mics are aimed at a 45 degree angle towards the ceiling, as opposed to a 90 degree angle straight at your face. That helps a lot and the Bose forum turned me on to that tip.

That's great input, we will give that a go.

[Herb Hunter]

I would use a feedback suppressor that automatically searches for the offending frequency and once it identifies it, attenuates it using very narrow band equalization. I have used a Sabine FBX Solo with good results but it is apparently out of production. You might want to have a look at this one which is even better:



http://www.bhphotovideo.com/c/produc...erminator.html

[Bob-I]

Originally Posted by Herb Hunter

I would use a feedback suppressor that automatically searches for the offending frequency and once it identifies it, attenuates it using very narrow band equalization. I have used a Sabine FBX Solo with good results but it is apparently out of production. You might want to have a look at this one which is even better:



http://www.bhphotovideo.com/c/produc...erminator.html

The problem there is that the Bose has no loop so we'd need one for each mic. We want a simple setup, not a complex one.

[Bob-I]

Everyone gave such great advise, here's my report...

Last week we setup the system, turned on the noise gate and tweaked the PEQ one mic at a time. I used my iPad audio kit app to visualize the feedback frequencies which was a big help. After ring in the frequencies we cut a .02 octave notch -3DB. After this we had quite a bit more volume before feedback, enough that it was uncomfortably loud in the practice room.

Last night we had a gig at a the same venue where we had feedback issues. We setup about 2' from the wall instead of flush against it. We tilted the mics up about 20 degrees and made no other adjustments. At almost 50% on the master we felt the level was right for the room.

Friends and family who came to the gig commented that the could sit at the table directly in front of us with no problem holding a conversation, exactly the same comment from people sitting 100' away and even the cooks in the kitchen.

We had 0 feedback, repeat zero, nothing, nada, not even a little ring in the background.

[jseth]

GREAT news! Glad you worked it out...

I'm telling you, those Bose L1 systems are SO vastly different from the conventional, that I frequently have to remind myself to "think outside the box" when I have to tweak anything on it...

And the comments you made regarding people hearing it, at the same volume, all over? THAT is one of the big reasons I love that system... because I can hear it as well as they can!