Double Bass Feedback: What frequency region(s)?

[DukeLeJeune]

I would like to get an idea of what frequency region (or regions) feedback typically occurs in, with amplified double bass. Knowing where to be extra careful will be beneficial to me as a cab designer.

Thanks!

 

[Vic Koler]

On my bass, I have a problem with the open D string. (73.42 Hz)

I would like to get an idea of what frequency region (or regions) feedback typically occurs in, with amplified double bass. Knowing where to be extra careful will be beneficial to me as a cab designer.

Thanks!

 

[nealw]

I think you'll get a lot of different answers. My half-size hybrid is pretty feedback-resistant but it seems like 120 hz tends to feed back first.

 

[DukeLeJeune]

Thank you very much, Nealw.

Before posting this thread I read or at least skimmed most of the threads with "feedback" in the topic, and recall someone posting that bumping down the EQ in the 100 to 120 Hz region was helpful. So even if you're playing a half-size hybrid, perhaps its natural resonant modes are similar.

 

[DukeLeJeune]

On my bass, I have a problem with the open D string. (73.42 Hz)

Thank you, Vic. Somehow I overlooked your post when I checked in earlier today.

 

[AMJBASS]

Every bass, and every room is different. Its tough to say exactly where you are going to find feedback.

 

[Jazz Ad]

It can be anywhere. There are several devices to help you tracking them, such as notch fiters and graphic EQs with feedback indicators.

 

[Slevage]

A parametric eq combined with the know how to use it is an invaluable tool.

My Acoustic Image head has a one band, sweepable that comes in very handy. Usually a notch is needed between
100 hz and 160 hz. But that frequency might be 108.xx,
115.xx, 138.xx............you get the picture.

john m

 

[DukeLeJeune]

Adrian and Jazz Ad, have you ever come across a situation where you got significant feedback (attributable to the bass cab) above 160 Hz? So far that's the highest frequency I've seen mentioned, namely by john m in the post just above.

If instances of feedback are all, or virtually all, occuring below 200 Hz or so, well that gives me a much better idea of what I can and can't get away with.

 

[Vic Koler]

The more I think about this I realize my problem may be with the 1st harmonic, which would put it @147 Hz.

As previously stated, it's different for every instrument in every room. The low frequency is the hardest to tame. I sometimes scoop out around 120Hz and boost a bit @40Hz to compensate.

At louder volumes I roll off the low end a bit to compensate for the Fletcher-Munson Loudness curves. I see an fDeck pre in my future.

On my bass, I have a problem with the open D string. (73.42 Hz)

 

[TimmyP]

Stage monitors and PA systems tend to be very heavy in the 125Hz to 250Hz region. With all this upper bass/low-mid energy floating around in the room, it would be wise to keep en eye on these areas (as well as have EQ to tame this if needed). (A lot of bass cabs are hot in the 160 range.)

 

[DukeLeJeune]

Thank you all very much, this has been quite helpful.

Duke