Acoustic Amp vs PA

[almeriastrings]

Personally, I really like working with the Fishman SA220's. We use two of them. They are very versatile, with direct outs, an Aux in which can be fed from a separate small mixer if additional inputs are required (we use an Allen & Heath Zed 12FX), and a very useful cross-feed mix capability where you can balance both towers in a "more me" type fashion. I use this for our own gigs, and also for some open mic type events - and I have had more compliments on the sound of these things than any previous system I have ever used. They sound extremely natural and uncolored, which is exactly what most acoustic performers are looking for, and you do not get that (to me) unpleasant 'split' between the stage sound and the house sound. All I can say is - it works for us very well indeed and while it may not work for everyone, in all cases, they (and the similar Bose system) are certainly worthy of consideration. For really big gigs, they are scalable... a fairly simple matter of taking a feed out to a larger system. That said, we have used just the pair to cover audiences in the 400 range with absolutely no problems at all. We do have a pair of Yamaha MRS-400 powered cabinets + stands that work well with them if required(rarely in our case, as we don't really 'do' stadium rock! - possibly because no-one ever asks us... we did do a large (for us) outdoor concert last year in a city park, however, with an audience in the 2,000+ range, and that little rig worked well and sounded good both off and on stage. For very small gigs (coffee house scale), just one tower handles it all very well.

[Tim2723]

We love our Bose systems for the same reasons. We have both the small Compact model and its big brother, the L-1 M2 'tower' that most people think of when talking about these things. For small venues we use the Compact alone with great results. For bigger venues and outdoors we use the larger L-1. But we can tie them together when needed. In one job we place the big L-1 out front as you would a conventional speaker and let it scream across the room. We put the smaller Compact behind us fed from the mixer's monitor output for stage volume.

So much of the capability of these unconventional systems comes directly from what Foldedpath was explaining: dispersion. The Bose towers use a number of small speakers that point off in different directions so that a large area is covered with a single cabinet. You don't get the 'single point' sound that can come with conventional cabinets. That's really my main complaint against using acoustic amps as PA systems for larger areas. They lack the dispersive characteristics needed to make a comfortable, controllable sound environment.

[Perry]

So much of the capability of these unconventional systems comes directly from what Foldedpath was explaining: dispersion. The Bose towers use a number of small speakers that point off in different directions so that a large area is covered with a single cabinet. You don't get the 'single point' sound that can come with conventional cabinets.

To me that is the biggest advantage of the Bose system. We recently picked one up and love it. Though we play many venues where PA is provided we still loving having the Bose when we need it.

You also hear what the audience hears. A big plus.

It really is impressive the first time you listen to a Bose and don't hear the typical laser beam audio effect of conventional systems.

The compact Bose seems the way to go in the PA vs. Acoustic amp approach.

[foldedpath]

You also hear what the audience hears. A big plus.

It's certainly an advantage with the Bose system to hear exactly what the audience hears, but that does come with one major downside: It limits what you can do for feedback control.

If you have to lower the volume to kill feedback, then you're lowering the volume for the audience too. If you have to "notch" some EQ frequencies to kill feedback, then you're taking frequencies out of the main mix that the audience hears. The situation is compounded by the way Bose recommends placing the towers towards the rear of the band, which might be in the pickup pattern of stage mics.

The advantage of the conventional approach with mains and monitors, is that feedback almost always happens in the monitors first, because they're closer to the mics and/or instrument pickups. So you can attack that problem separately; either by reducing stage levels or applying EQ to reduce the offending frequencies. Any EQ-based method of feedback control always compromises the quality of the overall sound, even a good narrowband system like the Sabine FBX I use. You can hear the difference when the unit is bypassed, so I usually run it only on the monitor side of the mixer output. The audience hears the clean, unaltered signal from the microphones.

And of course the other advantage is that a conventional PA setup places all the speakers on the audience side of the mics, in the deepest part of the rejection pattern for a typical stage mic. A Bose system can be placed at the front of the stage corners like a conventional PA, but you might not be able to hear yourself clearly without adding floor wedges or IEM's, and then you're basically duplicating a conventional PA setup.

If you never have feedback problems, then obviously none of this matters. For those of us who do run a lot of open mics onstage, a conventional PA with separate main speakers and floor monitors (or IEM's) offers much more control.

P.S. I know this is a conversation we all keep having here at intervals regarding the pros and cons of the Bose and Fishman "all-in-one" approach. But it's probably worth repeating for those who aren't familiar with these issues.

[almeriastrings]

I can only say that we very, very rarely have feedback problems, even in some very difficult rooms. Hard walls, floors, etc. We achieve more than adequate levels and need very little, if any, notch filtering. I do have a Sabine in the rack on our larger system, but don't even take that with us when using the Fishman setup. We also have a couple of DI's with built-in feedback suppression (Fishman Aura Spectrums) but again, have never needed to make use of it with this system. I am glad you mentioned off-axis rejection of mics, because I feel that is one area many feedback-related issues arise, especially when using stage monitors in close proximity. I try to get around that by not using conventional stage monitors whenever possible (I use a Sennheiser EW 300 IEM G3 system ), and by mic choice based on a lot of trial (and expensive!) errors over the years. With the Fishman system I mostly use AKG D5's (http://www.akg.com/fbid/) and Beyerdynamic M-201's. Both of these sound very clean and have a good transient response with exceptional feedback rejection. I don't usually bother with condenser mics on stage unless using an IEM system as I just find them too much of a pain in the rear when combined with conventional monitors..... you can get away with them with Fishman/Bose system, but a lot depends on the room... in a small room with hard surfaces, a typical cardiod condenser is likely to have issues no matter what system you are using. You could probably move the towers forward, and then take the direct outs to an IEM, but I have not tried that myself. I much prefer playing without monitors of any kind, if at all possible.

[Tim2723]

I too have seldom had any feedback issues with my Bose, indeed far fewer than I was used to with my conventional mains/monitors systems in the past. And like Almeria, I play in some very tough circumstances. Last night for instance we were standing right on top of each other with the Bose not two feet from my mic in a room so low that you could touch the ceiling. We had everything turned up past its comfort level. The mixer and power amp were all showing red clipping lights. We really needed the larger tower but there was no room for it (the ceiling is too low). Yet there wasn't so much as a suggestion of feedback all night.

I know it sounds contrary, but the problems any experienced person expects just don't happen. Even if you go to the Bose forum most feedback complaints are from those just starting out who treat the system like a conventional PA. Personally, it took me a while to forget what I knew about sound reinforcement. I had to trust that the engineers at Fishman and Bose were aware of the problems of putting a mic in front of a speaker. I don't know exactly how it works, but these things do just what they are advertised to do.

As an aside, last week I donated my old 'big' PA with its pole-mounted mains and floor wedges to the local fire brigade to call bingo games. I simply cannot foresee any circumstance where these systems won't work for me. The only job I have that is too big for them is the State Fair, and sound is provided there.

As to the topic of adding monitors, I can't speak for the Fishman, but you can stand behind the Bose and hear yourself with perfect clarity. We even played an outdoor job last summer and were surprised to find a couple of dozen people sitting behind us, listening contentedly.

As far as I can tell from direct personal experience, most of the feedback and monitoring concerns with these systems are largely theoretical.

[foldedpath]

As far as I can tell from direct personal experience, most of the feedback and monitoring concerns with these systems are largely theoretical.

Not in my case, I've seen people have feedback problems with the Bose system out here where I live, including another band that my duo partner plays in. They use a single Bose system. It's often ringing on the edge of feedback, especially in one venue that has a hard floor and fairly low ceiling.

Different venues can cause problems, but there are also differences in the way people amplify their acoustic instruments. If you use pickups instead of mics, then you've already got a little more gain before feedback to work with. Bands that rely exclusively on microphones (like the ones I play in) are in a different category.

Every performing situation is different, so it's just a question of choosing the right tools for the job. If people are using Bose systems without feedback problems, then that's the right tool for that situation. But I've seen it go the other way. Conventional systems can have problems with feedback control too, but they give you a few more tools to work with. That's all I'm sayin'.