PA system rebuild project

[DrummerLikesSpeakers]

Hello all
I'm new to this forum, a drummer and retiree that is looking into rebuilding my old p.a. speaker system. I have spent the last few months researching various design concepts and speaker components. My plan is to use my old pair of dual 15" Martin bass horns as subs for the time being with newly added mid-bass/high units for use in small to mid-sized environments.
Important objectives include lightweight modular units with good loudness and fidelity, requiring minimal processing.
I'm no audio expert but have designed/built some speaker boxes and believe I know enough to learn enough to come up with a good system that meets my needs.
And my budget is looking good.

Ever since I saw the Shindogs (house band for the mid 60's live music t.v. show "Shindig") play a local gig, using a pair of vocals-only JBL p.a. columns (each 4x10" w/two bullet tweeters), and after building my own cheap version (4x10" Utahs w/whizzer cones, no tweeters), I've been into the line source idea ever since. I know the point source concept has it's advantages (not the least being relative simplicity) and I now have some components, but the line idea is for me.

The key will be the high frequency section. I've read a couple of times that the planar lens waveguide is the greatest advancement in sound reinforcement theory to come along in the last few decades -- maybe so. I believe they are superior to various conventional types of tweeters, solving some basic line wave problems.
But I have run into problems trying to design them into trapazoidal line array boxes, so if I go with line arrays it probably won't include planar lens horns, unless I can be convinced otherwise. But I'm also not completely ruling out conventional tweeters -- that's still a possibility. My desire, though, is to incorporate a planar wave high end system.

Another option would be the ribbon line element, but I'm not sure that they are suitable for portable sound
systems. Lately the B-G 8" and 10" neo ribbons are hyped as now having more durable and higher performing diaphrams that makes them appear as a more attractive option than before. Being a shallow depth element, they would be easier to design into a trapazoidal box with a front-mount woofer.

The Paraline would be ideal, but after a phone call to VTC I know that they would not be available to me (unless I bought them as part of manufactured speaker boxes). And of course I've considered the synergy/unity horn - nice, but not quite right for me - costly to buy, tricky to make.

One of my biggest obstacles about deciding which way to go for high end is that I don't know how some of these components sound, particularly the ribbons. How do they sound in comparison to, say, domes (and I'm sure there's different sounding domes)? And does the planar waveguide horn lens have a good sound?

I have looked at the response curves of the B-G ribbons - not very flat.

There's also the question about crossover points relative to the vocal range, and how that relates to speaker configuration. Three-way units might be a bit much, two way more reasonable with a crossover around 1k (not the best for the vocal range)?

Although the woofers are important they will be a little easier to decide on. I'll be looking at using either 6.5s, 8s, or 10s. If I go with line arrays w/ribbon drivers, either 8s or 10s. I'm going to want woofer systems that will be able to carry some bass drum in a small setting (without needing subs). 10" woofers crossed at about 600 hz (for acoustic coupling) with 10" ribbons could be a nice combo for that, but enough 6.5s might do it, too.

Or I could just forego all this work and purchase something manufactured, such as:

the TOA HX-5, maybe eight units, mini line array http://www.toa.jp/products/pro_speak.../hx-5b-wp.html

the JBL CBT70J-1 + CBT70JE, pair, curvilinear line source http://www.jblpro.com/catalog/genera...?PId=419&MId=2

the CBN 6685, 4 units, ribbon line source

http://www.ribbonloudspeakers.com/

I know the TOA and JBL products use dome tweeters, not my preference, but do they perform well? They might spec out ok for loudness. That's something I don't know -- what can they handle?
I'm sure there are other great products out there.

Right now I'm leaning toward a modularized (small stackable modules) line source (column) system for ease of setup/use. I prefer the line array because of dispersion and wave control adjustibility.

Any thoughts out there?

[jont]

Re: PA system rebuild project

Have you looked at the BFM plans? I think the DR 200 would fulfill your needs.
I am not a fan of the Bose L1 pseudo line array but they can work in some situations I hear.

[DrummerLikesSpeakers]

Re: PA system rebuild project

As I mentioned I have been researching design concepts and components for awhile. Here are some of my mid-bass/high system speaker configuration ideas, beginning with:

ribbon line sources/arrays
Line array, trapezoidal modules, stacked/flown
10 inch
Faital Pro 10FE200 10" woofer x 12 http://www.usspeaker.com/faital%20pro%2010fe200-1.htm
Bohlender Graebener (B-G) Neo10 10" ribbon drivers x 12 http://www.parts-express.com/pe/show...number=264-715
x-over @ 600hz (there are 400w passive crossovers available)
Total driver costs: woofers ($720) + ribbons ($2280) = $3000.

8 inch
Faital Pro 8FE200 8" woofer x 18 http://www.usspeaker.com/faital%20pro%208fe200-1.htm
B-G Neo8 8" ribbon drivers x 18 http://www.parts-express.com/pe/show...number=264-712
x-over @ 800hz (400w passive crossovers available)
Total driver costs: woofers ($1080) + ribbons ($1746) = $2826
I prefer the 10" -- for one thing the woofer diameter and ribbon length are a better match. And of course the 10s are more productive in the lower registers (gotta hear that bass drum! ).

Line source, column modules, stacked/flown
6.5 inch
Faital Pro 6FE200 6.5" woofers x 18 http://www.usspeaker.com/faital%20pro%206fe200-1.htm
B-G Neo10 10" ribbon drivers x 12 (above)
x-over 600-800hz. Each module = 3 woofers, 2 ribbons.
Total driver costs: woofers ($954) + ribbons ($2280) = $3234

10 inch
Faital Pro 10FE200 10" woofer x 12 (above)
B-G Neo10 10" ribbon drivers x 12 (above)
x-over @ 600hz. Each module = 2 woofers, 2 ribbons.
Total driver costs: woofers ($720) + ribbons ($2280) = $3000.

I could also build 8 inch column modules @ the 8" line array cost. The 6.5" and 10" models are better woofer/ribbon matches dimensionally.

Planar lens horns
Line Source, column modules:
6 inch
Faital Pro 6FE200 6.5" woofers x 24
PRV Audio WG500 Planar Waveguide x 24 http://www.parts-express.com/pe/show...umber=294-2840
PRV D280Ti compression driver x 24 http://www.parts-express.com/pe/show...umber=294-2806
PRV 1" to 1.4" adaptor x 24
x-over: 1k hz
Each module = 3 woofers, 3 planar waveguides/drivers
Total driver costs: woofers ($1272) + waveguide ($1104) + CDs ($936) + adaptor ($240) = $3552

8 inch
Faital Pro 8FE200 8" woofer x 16
Faital Pro WG141 Planar Waveguide x 20 http://www.mcmelectronics.com/produc...PRO%2F01009255
P. Audio SD-75BF compression Driver x 20 http://www.loudspeakersplus.com/prod...P-AUDIOSD75BF/
x-over: 800hz
Each module = 4 woofers, 5 waveguides/drivers
Driver costs: woofers ($960) + waveguides ($2580) + CDs ($2400) = $5940

To match the planar horns and their length for a coherant wave, I'm insetting the woofers w/horn loading. I'm assuming the woofer parameters are acceptable for that.

More configurations with domes later.

[DrummerLikesSpeakers]

Re: PA system rebuild project

You replied while I was working on my addition, Jont. I have seen BFM's site and the DR 200 -- it looks good for what it is. I have alot of respect for Bill's products but I don't think that one is for me. As per my latest post, I believe my line array ideas are much more substantive than the Bose L1, although I'm sure it fits the bill for certain circumstances. And I did read the Bose L1 thread.

[jont]

Re: PA system rebuild project

The local club just installed a small format line array and I am not impressed.
The dispersion characteristics are not Ideal for the room but is "looks" cool, I would have loved to see a Danley system in there and it would sound twice as good for half the cost I am sure.

The size/weight/complexity of what you are proposing may be a detriment in a mobile live sound sound situation and keeping it simple can eliminate many of the gremlins that show up at a gig.

[DrummerLikesSpeakers]

Re: PA system rebuild project

Interesting about the newly installed small form line array. You would think that a line array would have the flexibility to "dial in" the precise desired dispersion characteristics, depending on the speaker configuration(s), but then I don't know the room. Do you know the speaker components of the boxes? How many boxes/side? They're not micro or mini arrays are they (like the TOA HX-5)?
I've looked at the Danley website -- are you referring to their synergy/unity horns? My impression is their products are excellent, known for clarity, but a bit expensive (?) Are you saying that perhaps your local club would have been better off with a point source system?
I agree that simplicity has it's advantages, but to a large degree line source/array systems are by nature great for dealing with those "gremlins". And I would have a lot of flexibilty with the columns since they would be modular, giving me total height options relative to things like ceiling heights (with accompanying acoustical challenges) and other physical characteristics.
If I wanted a simple, effective, inexpensive point source system I would probably go with the Peavey Impulse 12D http://www.peavey.com/products/index...e%26nbsp%3B12D point source cab w/1x12" + 1x ribbon driver/horn, 1200w biamp powered, 39 lbs each, about $600 each, run with subs. About the only thing I don't like is the woofer Xmax (about 3mm).

[DrummerLikesSpeakers]

Re: PA system rebuild project

Here are a couple of line source column module configurations using domes:

8 inch
Faital Pro 8FE200 x 18
Morel CAM 558 mid dome x 36 http://www.parts-express.com/pe/show...number=287-025
Vifa OX20SC00-04 3/4" (1.3") Fabric Dome Tweeter x 114 http://www.parts-express.com/pe/show...umber=264-1002
x-overs @ 750 hz, 1500 hz
6 modules -- 3 woofers, 6 mids, 19 tweeters each
Total driver costs: woofers ($1080) + dome mids ($2350.80) + dome tweeters ($1803.48) = $5234

Faital Pro 8FE200 x 24
Vifa NE25VTS-04 1" (2.6") Silk Dome Tweeter x 72 http://www.parts-express.com/pe/show...umber=264-1034
8 modules -- 3 woofers, 9 tweeters each
x-over @ 800 hz
Total driver costs: woofers ($1440) + dome tweeters ($2510.64) = $3950.64

Both of the above configurations could also be formulated for line array boxes.
All crossovers are configured to maintain acoustic coupling throughout the spectrum (except very high).
Domes were largely chosen with the low cutoff in mind. Ideally, in the two-way system, I would like to use smaller tweeters, but able to x-over @ 800 hz.
After reading other posts I wouldn't doubt there are better price deals out there on domes, such as buy-outs.

The above 3-way column module could be configured around a planar waveguide horn (1.5k x-over) with a face height of 4.81" and depth of 4.33" (coherant wave issue?), which could be quite costly depending on the chosen driver:
5 Faital Pro WG 101 waveguides x 6 (modules) = 30 waveguides x $62.00 = $1860

[Paul O]

Re: PA system rebuild project

You would think that a line array would have the flexibility to "dial in" the precise desired dispersion characteristics. Are you saying that perhaps your local club would have been better off with a point source system?
I agree that simplicity has it's advantages, but to a large degree line source/array systems are by nature great for dealing with those "gremlins". And I would have a lot of flexabilty with the columns since they would be modular, giving me total height options relative to things like ceiling heights (with accompanying acoustical challenges) and other physical characteristics.

You appear to be under the impression that a line array can fix any problem when in reality it's just another tool in the box with it's own unique set of limitations. For starters you don't get line array behaviour from 100hz up unless the stack-o-boxes is at least the same length as a wavelength at 100hz, so 2 or 3 "line array" boxes per side is just a funky looking(and behaving) point source system. If you do have a reasonable number of boxes stacked then the reward is very narrow vertical dispersion but also very wide horizontal dispersion.. which works very well outdoors and in wide-shallow rooms but is less usefull in a box shaped room and all wrong for narrow-deep rooms because it puts more energy on the walls and less to the back then a point source system would. And a line array really has very little adjustability unless each driver is individually powered and processed and that drastically raises the cost of investment.
All that said I like your ideas for this project and would like to see some sketches, in terms of output potential the CD loaded versions are gonna have an advantage but I can see you have a thing for ribbons.

If I wanted a simple, effective, inexpensive point source system I would probably go with the Peavey Impulse 12D http://www.peavey.com/products/index...e%26nbsp%3B12D point source cab w/1x12" + 1x ribbon driver/horn, 1200w biamp powered, 39 lbs each, about $600 each, run with subs. About the only thing I don't like is the woofer Xmax (about 3mm).

Now this is an interesting box that I didn't even know existed until today. I like everything about it except the look.. I've grown tired of plastic cabs without a full grill, but otherwise it's got lots of good technology in it and pricing puts it in direct competition with the QSC K, EV ELX series etc. Going back to the line arrays for a moment if you would be happy with this cab over subs then you won't be disappointed by a stack of 8's that have roughly 5 times the cone surface area, no contest there the array will produce more kick drum impact.. once it's processed properly.

[billfitzmaurice]

Re: PA system rebuild project

For starters you don't get line array behaviour from 100hz up unless the stack-o-boxes is at least the same length as a wavelength at 100hz,

3 wavelengths, actually. For all practical purposes even most pro touring line arrays are point sources below 400Hz or so.

[DrummerLikesSpeakers]

Re: PA system rebuild project

You appear to be under the impression that a line array can fix any problem when in reality it's just another tool in the box with it's own unique set of limitations.

Actually, I came into this project understanding everything you convey about line arrays and their limitations. As has been said by various sound scientists, to paraphrase, any speaker system is a collection of design compromises. I would also add to what you say about line array dispersion characteristics that it also depends somewhat on the splay of the boxes in combination with the length of the array, which can account for some of the kind of room characteristics that you describe. That is part of my approach of system modularization -- all of my ideas can execute different dispersion/wave formation characteristcs with different column or array lengths in combination with array splay and height location for a given room. That's why I prefer arrays over columns and point source -- you have the additional tool of adjustible splay to work with.

... but I can see you have a thing for ribbons.

I almost feel like I'm headed to coming full circle on ribbons. Back last autumn I was seriously considering diving right into ribbons until I talked to an engineer who cautioned me as to their weaknesses; that they were generally more delicate (not good for portable systems, of course), and that they can produce various negative dispersion characteristics that can be difficult to deal with. So I started looking in other directions. I recently started giving ribbons a second chance when I took a new look at the B-G Neo8 and Neo10, apparently with improved diaphram (Mylar-like) materials for greater durability and performance. And their off-axis response curves don't look too bad. I'm thinking that their face plates greatly effect dispersion charateristics for the positive. My only hesitation is with the not-very-flat response curves. But for me the bottom line is I'm partial to what works the best for my objectives at a reasonable cost.

[DrummerLikesSpeakers]

Re: PA system rebuild project

3 wavelengths, actually. For all practical purposes even most pro touring line arrays are point sources below 400Hz or so.

That surprises me -- I have always been under the impression that it was one wavelength, which seems logical.

[DrummerLikesSpeakers]

Re: PA system rebuild project

... if you would be happy with this cab over subs then you won't be disappointed by a stack of 8's that have roughly 5 times the cone surface area, no contest there the array will produce more kick drum impact.. once it's processed properly.

As much as I like 6s for their smaller footprint I think the 8s would do noticeably better for the kick drum without a sub, even than with more 6s. 10s would be better yet, but 8s would do the job.

[DrummerLikesSpeakers]

Re: PA system rebuild project

These are a couple of questions, specifically for Bill F., and for anyone else:

1. I haven't researched this -- what is the explanation for the "three wavelength" rule for the length of an array to faithfully propogate a given frequency?

2. Bill, concerning your SLA Pro PA top, are the tweeter elements ribbons? (I'm assuming so). And I'm assuming the rule would be to "snug up" multi-element mountings as close together as possible, with any extra space at the array ends, rather than putting any divided extra space of the cab face between the elements when building module cabs with stacking in mind.

[billfitzmaurice]

Re: PA system rebuild project

what is the explanation for the "three wavelength" rule for the length of an array to faithfully propogate a given frequency?

Read Jim Griffins whitepaper.

Bill, concerning your SLA Pro PA top, are the tweeter elements ribbons?

Piezos. Ribbons are prohibitively expensive, but you could use them if you wished.

[DrummerLikesSpeakers]

Re: PA system rebuild project

Thanks Bill -- very interesting. I think it''s the CTS KSN 1188 driver that is rated down to 800 hz (although the response curve casts some doubt) which could possibly work with one of my 8" line configurations on planar lenses. I'm not sure that I've ever heard those, or a model that extends down that low. Piezos often have a questionable reputation for their sound -- maybe a little "harsh". What do you think of their sound (the 1188?)? And are your SLA piezos with horns or planar lenses (I suspect horns)?
I certainly agree that ribbons are expensive -- I would rather go with another planar element option, better suited, at a lower cost, but there seems to be limited options. If only there was a way to cheaply produce a planar wave!