VOTE: an additional $250 for the feedback suppressor system

[John Clark]

Total expenditure would be $550. That includes the prior vote for $300.

Why?

The first feedback suppressor didn’t do anything to help feedback. The better unit is over $500 with tax.

This is not a “buy it and pay for it even if it doesn’t work”. The better unit will only be purchased where it can be easily returned if it doesn’t work out.

The first unit has already been returned.

Do we need it?

We had a feedback problem at the Sunday Narcan training meeting. And we see occasional feedback issues at Tuesday meetings. But slightly different situations will continue to cause feedback without a workable feedback suppressor. 

If you have questions or objections, I will be at the Tuesday meeting and also available before and after for questions and more detailed explanation.

[Kevin McLeod]

I vote no, for the same reasons as last time.  The solution is much more likely to be along the lines of adding sound absorptive and diffusive items to the ceiling, playing with speaker positions, and keeping the volume at a more reasonable level.  An expensive gadget doesn't seem warranted... 

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[Brad Walsh]

I vote yes

On Tue, Dec 14, 2021 at 11:47 AM John Clark <john....@hive13.org> wrote:

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Thanks,

Brad

[Dave B.]

Have any of the broadcast engineers we have as members given advice / guidance? Might as well leverage the experts among us.

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[Drew Kirkman]

In my opinion, some acoustic treatments in areas where we hold meetings would be beneficial. I don't know what form that would take in our specific environment, however. Just enough to take the RT60 down a little. I do not, however, think this would preclude the need for a feedback suppressor completely, because by the very nature of our meetings, there is going to be a microphone downstream from a loudspeaker at some point in all of them.

 
Drew Kirkman

IT Professional * Amateur Radio Operator (KN9FOO) * Hive13 CTO 2021-2022

Dr...@DrewKirkman.com

PGP: 8E9F E530 70D9 EA88 EE85 049F 4DCA 7B23 AA58 69B2 | cyph.me/kirkmawa

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[John Clark]

I have lowered the volume level because of complaints about how loud it is and brought in equipment to actually monitor the sound level. That is one of the reasons we have had fewer problems with feedback. 

I call the comments about the volume level complaints but I really appreciate them because I can't tell what is too loud for some other people and I would like to continue to get people's observations about the sound setup.

While I am not a broadcast engineer, I will say that is not really the same as working with live sound. 

Feedback is especially a problem when the microphones are in front of the speakers. Any time you get more sound going back into the microphone than it initially picks up, you will get feedback. More than unity gain gets you feedback. Whether it is sound or anything else.

Feedback suppressors typically work by "listening" for feedback and creating, either temporarily or permanently, very narrow filters in the frequency range of the feedback. This wasn't possible until things like microprocessors and DSPs came along.

Anyway the request is to try a better system and then see if it helps enough to be worth the expense. And to send it back if it doesn't. And I would bet that someone that specializes in public address sounds systems would say that you really have to try it.

For what it's worth I am an electrical engineer (with two degrees to show for it) and have over half a century of experience. Including a moderate amount of experience dealing with sound systems.

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[Marilyn Clark]

I vote yes for the feedback suppressor.

Marilyn

On Tue, Dec 14, 2021 at 11:47 AM John Clark <john....@hive13.org> wrote:

[malcolm.m...@gmail.com]

I vote yes.  

My point of view is based on my professional experience with acoustical assessment and design for speech reinforcement and intelligibility, which is what we're talking about here.  Very briefly:  I would agree with the relevance of comments about acoustical treatment, sound level moderation, and speaker placement vis-a-vis microphone location.  John and I spent a couple of hours looking and listening Thursday.  We walked around the room with the mics and tweaked the controls and confirmed that the feedback issue is dynamic, such that the resonances that cause it change with where the mics are located and which way they are pointed and other factors.  Given so much unpredictability, a good feedback suppressor/FBS (which tracks and notches out the offending resonances as they change with the physical variables) may be the simplest, fastest, and cheapest path forward.   I like the FBS because it is an easy to try, zero-risk potential solution with immediate results.    That it can be returned and John is willing to do the legwork makes it a no-brainer.  

FYI, John and I will be taking a deeper dive into Hive acoustics across the board - not just feedback and intelligibility, but also quieting some of the noisy machines.  We will take measurements that may help decide whether/how to proceed with acoustical treatment.   It would be helpful if anyone anticipating adding noisy equipment, or building walls or installing doors would get in touch with us early in the process.  It's a lot cheaper and easier to address sound issues during design than to fix them afterward.  Anyone who is interested in acoustics either to help or for curiosity's sake is welcome to join us.  John and I are likely to meet up before Tuesday's meeting to prep for it, time tbd.

I would propose another topic for consideration in 2022:  creation of a presentation space optimized for local and remote collaboration - where everyone, near and far, could see everything, hear everyone, and participate in discussion.  Usable for member meetings, guest presentations, either local or remote, originate webcasts.

[Kevin McLeod]

It sounds like y'all have tried more than I realized, and have thought things through. I'll change my vote to yes

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[Malcolm Montgomery]

John put a lot of research, thought, and time into this.  Leadership support means a lot.  Thanks Kevin. 

BTW, I won’t be attending Tuesday member meeting after all due to the evolving Covid situation.  I’m still open to talking to anyone interested in acoustics.

Sent from my iPhone

On Dec 20, 2021, at 8:02 AM, Kevin McLeod <kmc...@hive13.org> wrote:



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[John Clark]

I vote YES. Seems like I should for my own proposal.

[john.o...@gmail.com]

John O votes yes. 

[Rob Wetterer]

I vote yes.  

Thank you,

Rob Wetterer

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Thanks, Rob

[Tim Yelvington]

Yes

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[Kayla Lukawiecki]

I vote yes

[Dave Schwinn]

TLDR: I vote no. 

Most of our feedback problems could be solved if everyone didn't sit 30+ feet away from the speaker and have individual conversations while the meeting is going on.  If members were doing this for the sake of social distancing I would feel differently but as it currently stands the majority of people sit in a cluster.  This makes the online experience horrible as well.  Let's rearrange the meeting area to make sense and let's try sound dampening options.

[malcolm.m...@gmail.com]

I agree some sound absorption may be helpful, but it's a lot more time, work, and probably expense.  That's the first reason I favor the quick and easy trial of the feedback suppressor. 

As for moving everyone closer to the speakers (assuming the day comes when we can safely do so), that doesn't solve the fundamental feedback problem.  It may make it worse because the member participation mics will be closer to the speakers, and the variation in position and distance will be increased, making a dynamic correction all the more important.  IMHO, tempered by school of hard knocks.