GILDING THE LILY... THE WAMM BUSTER

[Roland N R]

Taking Altecs to the extreme level of performance has been one of my goals for years.

The Wilson WAMM has been a custom designed and expensive speaker held in high esteem. Once purchased for over $225K it arrives with Mr wilson to set it up for you!!! My goal is trying to match or surpass this level of performance on a budget using Altec gear.

Obviously the WAMM is a very large full range speaker. It uses a separate 15" vented subwoofer enclosure and uses a midbass, MR, Tweet, MR, set up. The tweeters are RTR electrostatic panels along with two 1". It takes the aproach of using multiple cone drivers with limited freq coverage to reduce distortion and increase efficiency. This makes for complex passive crossovers which are a secret in design being sealed in epoxy!!

Intrinsically horn designs are more efficient can have wider freq response per driver. They can play with very low distortion and have excellent transient response. But deep bass remains a problem because of the required large horns and extreme highs are also limited unless augmented with a dedicated tweeter.

So let the battle begin. Realize first these are not small room speakers they require a rather large room for best performance.

I have developed respect for the 210 enclosure with two 515g drivers it puts out 110 dB/w and is horn loaded down to 60-80 Hz. Modified as per Jim Dickerson (plus) the height can be reduced to about 5 1/2 feet with improvenent in bass response.

The large multicell horns are hard to beat for "home" use. They have an on axis flat HF response and with a 290 driver with phenolic diaphragm or 288 with Aluminun diaphragm provide excellent MR response till augmented with say a Altec 902 or other dedicated tweeter past their reduced HF point.

Subwoofers are a most to reach 20Hz and using horns is not realistic.. So a large vented enclosure with two 18" drivers per side or even better attic placed manifolds with four 15" with rear wave dissipating into the attic=infinite baffle subwoofers all crossed over below 80 Hz, get this job done.

So can basically an A4 augmented with subwoofers and tweeters and fine tuned to the max match or outperform the WAMM?? I believe it can as can a similarly augmented A5 or A7.

In addition their extreme Hi efficiency makes driving them easier allowing use of SET and PP DHT via hopefully multiamping. The subs of course will use Hi power SS amps.

With the money saved using this approach you can buy yourself a decent home Any comments or suggestions for improving this sytem will be appreciated.

[stpower]

Roland,
My A-4's are Dickinson modified,515-b,1003horn,288-L,JBL2405.I bi-amp at 500hz, use "T" passive networks to equalize the horns and bring in the JBL around 9k.PP Sound Valves M-60 drive the woofers, Welbourne Laurels SETs for the highs. I use the 210 box 211-style since the room is wide.I can tell you, bracing this enclosure makes a big difference. I especially stiffened and braced the horn flares more than Dickinson's article and it was worth it.Use the wings if possible; if you don't, brace&strut the long horn sides, they really need it without wings.
I suspect getting a good subjective blend between the sub and the LF horn will be hard. Nothing I tried yet was satisfying. Using the 290 and letting it roll off naturally simplifies crossover, you will just need a good tweeter that can go low enough. Some say the phenolics have the best midrange. Haven't been there yet.
BTW, the Wamm subs use 18" woofers vented. Don't know if you can match or better the Wamm, but the money saved will pay for the large room you will need.
Regards,
stpower

[Roland N R]

Stpower apparently not too many 210 users around...understandably since these are certainly not bose cubes!!!

Actually this surpass the WAMM stuff started as a bet with a local dealer that I match or surpass them for $2500 in parts!!...I started to scrounge up appropiate non horn hi quality drivers but then along the line I discovered Altec and horns. Immediately I recognized the potential and switched to an all horn design except for the subwoofers. Granted much fine tuning needs to be done on cabinets, flattening the freq response and extending the highs and lows but intrinsically the dynamics and resolution are superb. Those two are usually the irreversable quality limiting factors in other systems.

Adding subs, tweeters and fine tuning easily converts A4, A5, and A7s into full range world class performers. I was not very impressed with the WAMM in comparison but did not directly A@B ( 210s too heavy to move). The store rep acknowledged it was close and within the price limit. I had worked hard to earn that beer! By the way present WAMM 7a components per speaker are 9 RTR electrostatic tweeters, two 1" tweets, two 4" MR, two 6x9" midbass,and one 15" sub in vented cabinet.. All drivers are basically "souped" up over the counter stuff. Granted Wilson's expertise is priceless!!

[GM]

As much as I liked my much modded 210s, if I go in this direction again it will be with a different horn configuration to eliminate the parallel walls, though they will still be dual 515B loaded. WRT the HF, the multicells have their strong points, but for my tastes I found the modded 511 a better all around performer in the two different rooms they were in. In retrospect I might have a different POV had I tried the 1803s since they have so many cells, but the 805/1005 interacted too much with the rooms and had too much audible comb filtering for me. Regardless, if I go down the big horn path again it will have a 250-300Hz Unity concept 'clone' perched on top and a Contrabass to handle below 80Hz (as before).

Really though, to guarantee blowing the doors off any consumer design likely to ever come down the pike, and even the 210 combo would be a 80Hz Unity concept 'clone' and a pair of Contrabasses/chnl.. You'll need a really big room to get the most out of this system though, ~45ft x 72ft minimum, considerably larger than my whole house so it's just a dream system for me.

GM

[Russellc]

FWIW,
As far as I'm concerned, most any up to snuff A-7
is the one to listen to when compared to wilson anything. I once listened for some while to a set up consisting of the watt puppy and mark levinson cd, pre amp and 2 hugh levinson mono block. It sounded OK, not really that great. The sound treatments alone were probably worth more than the
average good system. The Wilson stuff is really not comparable to the altec, they are two different animals....ever see a wamm or wilson anything used as PA? Of coarse not! 225 grand for a speaker? Give me a break! I don't care who comes to set it up.

[Roland N R]

Yes GM you are right.

It seems we are getting carried away with the desire for ultraefficiency in the home setting. It is resulting in enormous size systems with horn subs etc. Often these things are 12 or more feet high. Then they proudly shown in pictures in the net more often resembling a wall of sound reinforcement drivers. The 210s I have will be used in an appropiate outdoor setting in a tennis court.

That servodrive contrabass sure looks nice but again too big for most settings.

Also that MR/T combined horn looks interesting but I already have too much stuff.

My next speaker will be a 100dB/W small monitor with invisible subwoof. Even the wife will like it!!