Although I have been building speakers since 1955, (Yes I'm an old duffer but I can still hear to 15K ) I have not played in the Full Range arena since my early engineering days at Admiral Corporation. For the youth on board, Admiral was once the largest manufacturer of TV and Radio in the world. Anyway, in those day it was all full range speakers. In the Console TVs and phonographs it was a 10 or 12 inch in an open back "enclosure". ( Utah was one our suppliers) Fs was about 70Hz and we limited the high end to 8 kHz, even through TV sound was FM. The cones were all paper but the "high end" models had curve linear cones. When stereo came out in 1959 we added cone tweeters, with a single 8 uFcrossover cap, and extended the range to 15 kHz on the phono consoles. Most of the early stereo cartridges we used were ceramic which cut off at about 11 to 12kHz.
The only good speaker system Admiral ever had was the 1972 "Bullhorn" it was nothing but a 3 inch large Xmass driver in a transmission line enclosure and it had great bass for the size of the driver. The magnet was a 7 Oz Alnico. Some years ago a guy had a web site on them and he collected the drivers. I happened to have two of them so we made a deal. That was 12 years ago and the site is no longer up. I'd like to have a pair again to play with. Admiral folded in 1978, a victim of the Asian electronics invasion.
The only good speaker system Admiral ever had was the 1972 "Bullhorn" it was nothing but a 3 inch large Xmass driver in a transmission line enclosure and it had great bass for the size of the driver. The magnet was a 7 Oz Alnico. Some years ago a guy had a web site on them and he collected the drivers. I happened to have two of them so we made a deal. That was 12 years ago and the site is no longer up. I'd like to have a pair again to play with. Admiral folded in 1978, a victim of the Asian electronics invasion.
Ken,
Are you talking about the Tunnel Reflex with the Foster "FE103A", and this web page?
Transmission Line Speakers
I think the guy you are talking about is me, and i'm still here 🙂
(not the ones you sent me which were unique among the ones i've had)
dave
Yes, now I remember you Dave. Glad to see you are still in action. I could not remember who the supplier was for those speakers but I do remember that the marketing guys said they were too expensive to make and they killed the product.
Admiral had two marketing names for the "Tunnel Reflex" the other was the "Bullhorn".
The cabinets were among the last made in our own cabinet plant in Indiana. Admiral had been sold to Rockwell International in 1971 and they quickly starting closing plants and moving most electronics production to facilities in Taiwan. By 1978 they were history.
In the 1950s Admiral had a record changer plant in Dixon, IL. They made thousands of them for their own products and for OEM customers.They used one of the first ceramic
mono cartridges made by Shure, ( Another company I later worked for in Chicago) Those changers had a simple mechanism, worked very well, and are a collectors item today.
The cabinets were among the last made in our own cabinet plant in Indiana. Admiral had been sold to Rockwell International in 1971 and they quickly starting closing plants and moving most electronics production to facilities in Taiwan. By 1978 they were history.
In the 1950s Admiral had a record changer plant in Dixon, IL. They made thousands of them for their own products and for OEM customers.They used one of the first ceramic
mono cartridges made by Shure, ( Another company I later worked for in Chicago) Those changers had a simple mechanism, worked very well, and are a collectors item today.
My web site has a couple of line arrays I built and the May 2008 edition of Audio Xpress covered my line array with a side firing woofer. My experience is that most small driver line arrays require a lot of bass equalization or be used with an outboard sub woofer. The Audience A3 may be an exception, as it has a large Xmass. Line arrays are like transmissions line systems in that a lot more research needs to be done to come up with a predictable design outcome. Line arrays do provide good imaging and low distortion. They can cause phasing problems and resultant frequency combing at varying distances from the speaker. Line arrays built with "cheap" drivers sound like line arrays built with cheap drivers. Use good quality three or four inch drivers with the highest Xmass and lowest Fs with a minimum of four drivers per side. Keep the front panel as narrow as possible to accommodate the driver and you can come up up with a good sounding system.
Why did those little drivers have such wide surrounds when the xmax was virtually nil? One would think you could get more cone area by limiting that surround to a half roll only a couple mm wide.
Scott,
I was wondering if you could tell me if you had any drivers in mind that could be used for the rear line if one were to use 4 or 8 A3 drivers for a DIY line array?
These drivers seem pretty interesting. I am kind of surprised that there aren't more DIY projects on the forum.
I guess the price of the drivers is one reason.
-Nick
Does anyone know if it would be possible to use the A3 drivers in an open baffle design with multiple drivers per speaker?
Fairly recently there has been an "explosion" of small drivers - so you have a lot to choose from.
Aurasound (..and Dayton),
Dayton,
Fountek,
HiVi (swans),
MCM Electronics,
Peerless, and particularly
Tangband
Just look at all of Tangbands drivers ("tweeters" section and scroll down to "Fullrange"):
Tangband Speakers
One of many sources:
EXTENDED RANGE CONE DRIVERS from Parts Express ship same day and come with 45 day money back guarantee. Free Shipping Available. Order free 10,000 product catalog.
..and you can even find some measurements from some of the drivers here:
Zaph|Audio
..more specifically look to the Dayton RS125 (found tested at Zaphs), it's a little larger but with pretty good harmonic distortion figures (especially at lower freq.s) and a decent eff..
BTW, if you are just looking for a Full-Range Line Array that is overall well designed then look here:
http://www.diyaudio.com/forums/full-range/157960-tony-gees-line-array-up.html
Really though, I wish Tony had used the Fountek FR88-EX for this design (..but it might not have been available at the time). If he had then harmonic distortion wouldn't have been so high below 150Hz.
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It's always possible to do this. The real question is:
-is it a good idea?
IMO, it isn't a good idea.
One of the things that can make a small driver array sound "special" is the relativly small baffle width - that tends to allow better imaging despite higher freq.s emanating from something larger than a 1 inch tweeter *with* attendant aberrations in response due to combing.
Now IF you keep with a narrow baffle then you will have baffle loss starting *way* up in freq. with your -6 db an octave loss. Taken over several octaves it dramatically impacts your over-all loudness, and even modest sound pressure levels (when eq'ed flat) will have considerable harmonic distortion.
The alternative is a very large baffle, or some hybrid design that uses physical extensions to increase baffle area. Doing this of course will bring it's own benefits, but IMO the cost is to high. 🙁
BTW, if it were me personally (and I was interested in going back to this type of design) - I'd email Tony and see what his thoughts are on alterations to his design with the use of the Fountek FR88-EX, provided I wasn't intending to use a "flea watt" amplifier. That would put the drivers alone at about 350 per loudspeaker assuming some discount on drivers and shipping - expensive, but not outrageous.
Don't forget Fostex... they have 2 very good 3" plus an outstanding one.
And Visaton, Ciare, Mark Audio (Alpair 6)
dave
Indeed, my bad. 😉 (..and there are probably many others as well, certainly Fostex parent Foster has a whole range of the stuff, but most of which North America will never see. 🙁 )
Thanks Scott for pointing out some other options.
I am not sure how important the rear bipole line would be if I did a sealed line array with the A3.
I guess there is one sure way to find out.
I appreciate your input Dave.
Thanks for your patience in answering all my questions.
I am not sure how important the rear bipole line would be if I did a sealed line array with the A3.
I guess there is one sure way to find out.
I appreciate your input Dave.
Thanks for your patience in answering all my questions.
Your welcome!
The bipole is primarily there to fill in for baffle-step compensation without filtration and a loss in overall sp-level. (..depending on baffle width say between 600 and 90 Hz.) It should also provide some additional higher freq. far enough off-axis from the front line that it doesn't comb around to the sides at those higher freq.s. (..of course this can be done with a simple low-pass filter as well.)
A design like Tony has doesn't need the bipole line because he has to eq. (flatten-out) the freq.s of the array because unlike the Audience driver, the HiVi driver he is using doesn't have an increasing response in the treble region.
Note the 32 2" driver line array here and all the acoustic gain it gets under 1.5 kHz:
Parts Express: Project Showcase
Those 2" drivers don't have much treble rise either (single driver response):
http://www.parts-express.com/pdf/264-806g.pdf
- the array is "flattened out" with eq. the entire midrange is "knocked down" to the level of the treble output of the array (aprox. 6-20 kHz). (..though in the case of the Kuze he is actually *increasing* the output of the treble region instead (actively), which is basically the same thing - requiring more output from the amplifier.)
Any commnets about this idea adding alternative rear-firing drivers for BSC to an Audience A3 driver array, as follows?
An inexpensive way of adding rear-firing mid -woofers for "BSC" (Baffle-Step-Compensation):
An alternative to using extra rear-firing A3 drivers would be an active driver BSC approach. Use the 5" Zaph Audio aluminum cone driver (7 gm moving mass), # ZA14W08, - use half as many of these rear/side mounted 5" drivers for BSC as the number of front-firing A3s (roughly equivalent Sd, cone area). Aluminum cone material may offer similar sonic signature as the A3 driver? Add separate interior baffle partition to the cabinet to isolate the A3 drivers from the 5" woofers.
However, there may be a "showstopper" to this approach: The mid and upper bass CSD (spectral decay) of the more massive 5" driver may not be as good as the Audience A3 (2.5 gm moving mass spec). This CSD of the 5" driver might just "muddy-up" the overall sound quality for which the A3s are famous - even though the 5" drivers would be rear-firing to attenuate the trebles (also might cover 5" driver with some foam to further reduce high frequency radiation).
Perhaps the only way to ever be sure is to construct an experimental speaker and do measurements, and most of all, listen.
If the sonic clarity is relatively unaffected, then it's a good thing to pursue.
If a passive radiator with an A3 array doesn't reduce perceived sound quality, then maybe a good 5" rear firing driver for BSC might not be too bad? Sometimes we hobbyists learn the hard way -- by trial and error ...
A passive-radiator prototype Audience "2+2" was sucessfully demo'd at the 2010 Show (there's a picture on internet).
Bill
An inexpensive way of adding rear-firing mid -woofers for "BSC" (Baffle-Step-Compensation):
An alternative to using extra rear-firing A3 drivers would be an active driver BSC approach. Use the 5" Zaph Audio aluminum cone driver (7 gm moving mass), # ZA14W08, - use half as many of these rear/side mounted 5" drivers for BSC as the number of front-firing A3s (roughly equivalent Sd, cone area). Aluminum cone material may offer similar sonic signature as the A3 driver? Add separate interior baffle partition to the cabinet to isolate the A3 drivers from the 5" woofers.
However, there may be a "showstopper" to this approach: The mid and upper bass CSD (spectral decay) of the more massive 5" driver may not be as good as the Audience A3 (2.5 gm moving mass spec). This CSD of the 5" driver might just "muddy-up" the overall sound quality for which the A3s are famous - even though the 5" drivers would be rear-firing to attenuate the trebles (also might cover 5" driver with some foam to further reduce high frequency radiation).
Perhaps the only way to ever be sure is to construct an experimental speaker and do measurements, and most of all, listen.
If the sonic clarity is relatively unaffected, then it's a good thing to pursue.
If a passive radiator with an A3 array doesn't reduce perceived sound quality, then maybe a good 5" rear firing driver for BSC might not be too bad? Sometimes we hobbyists learn the hard way -- by trial and error ...
A passive-radiator prototype Audience "2+2" was sucessfully demo'd at the 2010 Show (there's a picture on internet).
Bill
I have pretty much settled on trying a speaker project using 4 A3 drivers per speaker.
I am not going to use any side/rear firing drivers like the 4+4 by Audience.
I have a question that hopefully one of the experienced speaker builders can address.
How important do you think the shape of the cabinet will be for this design?
I noticed that Audience has a sophisticated 15" wide baffle with large rounded sides.
I read the review on Soundstage and it describes the cabinet construction being built using mdf pillars that are sanded and used in the baffle construction.
I am not worried about getting these speakers to perform the lowest bass duties. I am going to use helper woofers (open baffle) for the lowest frequencies.
I appreciate all the advice and help with my questions.
-Nick
I am not going to use any side/rear firing drivers like the 4+4 by Audience.
I have a question that hopefully one of the experienced speaker builders can address.
How important do you think the shape of the cabinet will be for this design?
I noticed that Audience has a sophisticated 15" wide baffle with large rounded sides.
I read the review on Soundstage and it describes the cabinet construction being built using mdf pillars that are sanded and used in the baffle construction.
I am not worried about getting these speakers to perform the lowest bass duties. I am going to use helper woofers (open baffle) for the lowest frequencies.
I appreciate all the advice and help with my questions.
-Nick
The box can make or break a project.
I believe there is an article at the decware website talking about placing an am radio (on to talk) in a speaker box then installing the speaker. The sound you hear is very close to the sound coming off the back of the drivers that is bouncing around and then coming through the cone.
Ideally the enclosure would be an egg, but if you ran .618 : 1 : 1.618 then had some of the black hole #5 (or some partsexpress stuff) then poly fill, you are off to a great start.
The size of the baffle affects baffle step. Look into all the info on that.
I like huge baffles because otherwise you have to boost the bass by 3-6db which modulates the midrange (sounding blurry).
Then you can look into rounding the edges, but I don't think that the highs from a 3-4" driver smear the edges at all compared to a dome tweeter.
The soundstage review, well there was no measurements.
Combing is real, but perhaps in a short line it isn't too bad at 10' away.
Remember Audience has to make it look great (as do most once the price goes past $1,000). I've been intrigued with the driver, but not at $170 each.
I wouldn't worry about how quick a baffle step or woofer is. Most of that sound is like mud. If you disagree, then run your 3 way without mid and tweet, then get back to me with an apology (lol).
If I remember correctly, the peerless tc9 from madisound (having half the xmax) is around $10-$15 and has the same frame size. I'd try 4 of those first (build a proof of concept first) then when you know all the + and -'s of a short array, then invest in pricier drivers.
If you can make it yourself, I recommend a 24" wide baffle, but you will have to adjust the front edge to aim the speakers at you. I have a dual 5" frame speaker than I had to use pennies to zero it in sitting 12' away.
Remember that the A3 driver has a lift in respose past 1khz, good for a short array, unlike the tc9 or most 4" designed to be fairly flat.
Norman
I believe there is an article at the decware website talking about placing an am radio (on to talk) in a speaker box then installing the speaker. The sound you hear is very close to the sound coming off the back of the drivers that is bouncing around and then coming through the cone.
Ideally the enclosure would be an egg, but if you ran .618 : 1 : 1.618 then had some of the black hole #5 (or some partsexpress stuff) then poly fill, you are off to a great start.
The size of the baffle affects baffle step. Look into all the info on that.
I like huge baffles because otherwise you have to boost the bass by 3-6db which modulates the midrange (sounding blurry).
Then you can look into rounding the edges, but I don't think that the highs from a 3-4" driver smear the edges at all compared to a dome tweeter.
The soundstage review, well there was no measurements.
Combing is real, but perhaps in a short line it isn't too bad at 10' away.
Remember Audience has to make it look great (as do most once the price goes past $1,000). I've been intrigued with the driver, but not at $170 each.
I wouldn't worry about how quick a baffle step or woofer is. Most of that sound is like mud. If you disagree, then run your 3 way without mid and tweet, then get back to me with an apology (lol).
If I remember correctly, the peerless tc9 from madisound (having half the xmax) is around $10-$15 and has the same frame size. I'd try 4 of those first (build a proof of concept first) then when you know all the + and -'s of a short array, then invest in pricier drivers.
If you can make it yourself, I recommend a 24" wide baffle, but you will have to adjust the front edge to aim the speakers at you. I have a dual 5" frame speaker than I had to use pennies to zero it in sitting 12' away.
Remember that the A3 driver has a lift in respose past 1khz, good for a short array, unlike the tc9 or most 4" designed to be fairly flat.
Norman
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