High Efficiency, Professional,.......... not bookshelf size speaker systems


Oct 28, 2020
Warrensburg, Missouri
This is all............." in my opinion ". :

In a prior posting this week, I suggested that when using High Efficiency speakers to enjoy the best possible audio playback, simply employ two PROFESSIONAL- quality drivers.

A simple TWO-WAY !!

This simply means to avoid any and all commercially " designed for the consumer market " loudspeakers.

For this PROFESSIONAL speaker, EACH driver ( 15 inch woofer and tweeter ) is individually FRONT horn loaded, both are naturally time aligned, ( voice coil distance- wise, one to the other ), and both drivers must each individually be very carefully compression-loaded .

Several months ago, I posted on HFV that there are three worthy PROFESSIONAL quality drivers I know of, to recommend.

1) Vintage German Klangfilm PROFESSIONAL speaker systems. Sadly, most were lost during WW II.

2) Vintage PROFESSIONAL use ALTEC drivers.....416Bs, 802Ds, and 515Bs. Happily today, we still have GPA making such drivers, brand new.

These GPAs use ferrite magnets, which are generally superior to vintage alnico models, because of how the magnet structures are shaped in a superior fashion, putting the magnetism where it does a better job.

The GPA drivers play louder than their vintage counterparts, and can be usually someone's best driver choice. ( GPA is Great Plains Audio.) I would love to trade for the new GPA 515H model, instead of my vintage ALTEC 515Bs .

3) From Japan, we have ALE drivers. ALE PROFESSIONAL compression drivers are very expensive, and are precision manufactured and assembled on a " parts blue-printed " level. These are fastidious Japanese copies of vintage ALTEC designs. Available new, NOW. Open your wallet.

A single ALE compression driver might cost USD $100,000 each or so, just an unconfirmed wild guess. I actually have a audiophile friend who owns a FOUR ALE driver-per-side home stereo set up, using Dennis Fraker's Serious Stereo DC SE amps for his home system.

There was a recent audio exhibit in New York City, last month or so, where some PROFESSIONAL quality GPA components were continuously demoed in a ART Gallery exhibit. Many videos are on line. I like JE Lab's write up, because he gives us the actual components used. See it here :

The thing I personally enjoyed with JE LAB's write up was

a) the use of some GPA professional drivers, and

b ) that the exhibitor's SE 300B amp ( LOL, with mis-designed filaments as used in the new Western Electric 300Bs ) was a take off, a homage to Herb Reichert's Flesh and Blood 300B amp. Said amp was featured in Sound Practices magazine in the 1980s. I personally indoctrinated Herbie into low DCR choke implementations, early '80s. I explained to Herbie how my then-audio Mentor, Robert W. Fulton, taught me immediately that " all chokes have to be 20 Ohms or less " IF " I can find them. "

When Flesh and Blood photos appeared in the magazine, I got to see - what we were both using. Not 20 Ohms, but a surplus-priced ESPEY 3 HY at 24 Ohms DCR choke, which as I recall, surplus, was only $ 6 or 8 USD each - the best I could source then. Fair Radio Sales. Today, we can use two Hammond 159ZAs regularly, as in L1/C1/L2/C2 to the Finals. The 159ZAs are 6 Ohms DCR each, and it works well. ONLY 12 ohms total in DC Resistance. Good enough to boogie, be on-time, on pulsed music information.

' Back to PROFESSIONAL drivers :

In the mid 1990s, I was fortunate enough to buy a vintage ( 1940s ) RCA Movie Theatre speaker set up . I was using RCA MI-9462 " Ubangie Lips " bass horns, had four enclosures, used two. It used two 15 inch drivers per front firing bass horn. Owned eight delicious sounding RCA MI-9449 15 inch drivers. Used RCA radial high frequency horns. Also collected six RCA war-era Field Coil Compression tweeters, four MI -1428B / and two MI-1443s. Awesome compression drivers, look them up. My four bass horn enclosures were each " cut off ", on one ( of two ) reflex port's side.

Jeff's tube amp knowledge was not up to snuff, in that mid-90s time, VS now. Was doing tubes/ triodes Push Pull rather than Single Ended and Directly Coupled.

In the later 1990s, I had to move to New York City. Not having room, I sold almost all my RCA PROFESSIONAL gear to Johnathan Weiss of Oswald Mills Audio fame. These two SUGGESTED videos will give you a decent background as to these RCA Professional audio components. The eight minute second video is highly informative.

For the last six years, ( 2016-2022) in a small apartment in the MidWest USA, I run a mildly modded ALTEC A7-8 with 515Bs and 802Ds, and my latest DC amp as shown on HFV..........in 2021. My room is 12 by 15.5 feet. A7-8s will work in a one car garage.

I am so very happy. It is exciting and so much FUN to hear and experience now.

Thanks for sharing my journey in audio. Dad started me with the original Field Coil ALTEC 604s, 77 years ago as a new baby. I am still a baby.... just not new. Amazing.


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A 15 or 16 inch woofer, loaded into an ALTEC 825 enclosure's 8 inch across vertical woofer opening slot, compression loads the 15 inch woofer's cone !!!! How many of you have ever thought ............. about that !!!!!

Both drivers are properly FRONT horn laded, compression-loaded, intrinsically voice coil time aligned, etc.

Honestly. I do not like 15 inch drivers mounted on a flat baffle, ALTEC , JBL, Tannoy, Klipsch ( last two are not PROFESSIONAL drivers ) you name it. None will compare to an A7-8 and this design, at all !!! No offense meant to anyone. It is all IMHO.

MOST ALTEC A7's and A5s I see and hear, are poorly set up, starting with a poor tube amp and wiring !!!!! Unimpressive. 90% of the stock internal fiberglass padding MUST to be tossed away. But not the enclosure. Enclosure plans are on line, with only a few very minor changes being beneficial. WHICH ONES ?? Ask me !
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Those RCA Ubangi are legendary…. Unparalleled.

Horn loading drivers from the front, takes the setup to another level which can only be experienced.

I might be able to churn up 3 ohm DCR chokes….
Those RCA Ubangi are legendary…. Unparalleled.

Horn loading drivers from the front, takes the setup to another level which can only be experienced.

I might be able to churn up 3 ohm DCR chokes

I can help you with PSUDING the supply and adapting it to your DIY amp.

When you have dual 5U4GB rectifiers, and low DCR chokes ( 6 Ohms or less ) you will also come to TRULY appreciate a speaker system with compression loading on both that woofer and tweeter ! ( In addition to a front horn load on each of those two drivers. ) The classic ALTEC 825 enclosure also uniquely time aligns the voice coils .

Yogibear, I lately am so " blown away " with my latest A7-8 set up, and what it does dynamically with the 2021 HFV Type 6005 stereo amp and GTO caps in use. INCREDIBLE..
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Hi Jeff,

Thanks for the write up.
Can you please advise us about how to achieve a reasonable standard of sound quality with "available" components (Drivers and all) in India.
For most of us it's almost impossible to get those drivers you mentioned.
Even if we get the 802+416 Altec drivers somehow, how to make those VOTT cabinets?
Can you please guide us on the cabinets so that we can DIY them?
Also please guide us on the crossover for 802+416B in VOTT A7/A5 cabinets.

Hi Jeff,
Excellent write up. Pleasure to reading your experience on altecs A7 cabinets and your DIY tube Amp.

Fortunately I have most of the 'professional' speakers you mentioned here ( Klangfilms, Altecs, JBLs, RCAs ...).

Will ask your advice on my next speaker project, soon.

Thanks for sharing your valuable suggestions.
Hi Jeff,

Thanks for the write up.
Can you please advise us about how to achieve a reasonable standard of sound quality with "available" components (Drivers and all) in India.
For most of us it's almost impossible to get those drivers you mentioned.
Even if we get the 802+416 Altec drivers somehow, how to make those VOTT cabinets?
Can you please guide us on the cabinets so that we can DIY them?
Also please guide us on the crossover for 802+416B in VOTT A7/A5 cabinets.


Nice honest post !!! Thanks.

There is much ALTEC information on line, places like " Lansing Heritage", etc. with enclosure data on A7 Type 825 ( the early ) enclosures. Look at this as an EXAMPLE :

825 Enclosure PLANS.JPG

I am NOT a speaker expert. But Dennis, my audio mentor of the last 30 years or so, IS a fabulous ALTEC and audiophile / audio expert. He was a movie theatre Technician for theatres in a several USA states area ( ran a company he called Cinema Designs ) , bordering his home in Livingston, Montana, and into parts of Canada. He uniquely has many decades of hands-on experience. Direct knowledge.

Additionally, he personally has also owned and operated several cinemas. He would buy a business, re-do / improve the venue, and resell the new Cinema at a profit. He would typically use up to eight A7-8 speakers in a larger sized venue. I am sure he has either purchased and / or worked on hundreds of A7-8s in his decades long career.

For decades, I was " mentally wrapped up with INefficient speakers. This error was compounded " as a result of speaker designs by my gifted first audio mentor, Robert Fulton.

I was associated with with Mr. Fulton like Father - Son from our first meeting in 1978, until his death September 15, 1988. It was Robert, who instilled within me the idea that audio amps were the weakest link, not loudspeakers, in any audio high performance chain....and that very FEW of the amps then ( and certainly today ) ever can " cut the mustard ".

Yes, I had lots of RCA " Ubangie " PROFESSIONAL speaker ownership experience during the 1990 decade. But I was inadequate in my DIY amp building - speaker interface knowledge during those 1990's years.

In about 2010 to 2016, ( at my second audio mentor's urging - Dennis ) I finally acquired the better ALTEC PROFESSIONAL speaker components.

It took me several SE DC DIY triode amp builds / designs, from the year 2000 on, to get truly " acceptable " amps - to best run such speakers. It was not until my prototype July 2019 KT88 amp build - that I finally figured out how to SOLVE and build a " fabulous-performing amplifier ", ( beyond all else anyone living I would imagine can own. )

The HFV 2021 stereo 6005 amp build, nicely documented here on HFV, has much good information on what it took. Offered thankfully for posterity.

From about 2016 to about 2020, I did extensive experimenting, with input from Dennis, on what to do to my 825 enclosures. LOL, almost ALL the things I ( or you ) can read on line, speaker/crossover mods for ALTEC, the written " expert " advice, was wrong.

I trusted NO ONE, and used my own EARS, ( and input from Dennis ) to arrive at what works best ( for me ). I am very confident in my results in 2022.

A little background, second hand, on 825 enclosures. This design is not a pig in the poke. The PROFESSIONAL VOTTs were adopted by the Motion Picture Industry as THE enclosure reference / accepted STANDARD, for many years .

Dennis always tells me " The ALTEC engineers, got the design right basically, to start with " and very little has to be done ". Dennis will also say to me, guessing of course - it is possibly, after all these years, still capable of being perhaps one of the world's best performing speaker designs, in THIS day and age, when executed extraordinarily - well.

Back to the 825 enclosure. I think the 825 is the first of three versions. It has a tendency to " wiggle " and lose energy inside the enclosure. Both of the later ALTEC enclosure versions sound better, even though similar looking. BUT, simple mods can be done, to the basic 825 design, and get the first version to "go" . ( My own 825 enclosure mods, done 100% by ear. ).

Two weeks ago, I asked Dennis what could be done if someone were to scratch build a 825 in 2022. It was theoretical. He said, " simply make the exterior walls out of 1 1/8 th inch marine grade plywood. " Leave the inside dimensions and wood thickness alone...no added internal bracing, damping internal, etc.

There are limitations to a two way 825 enclosure. No extreme bass, below 40 HZ. that is FINE, because I have the best MID bass I have ever heard anywhere, with my set up !!!
All else is exceptional, super - FUN, unique performance, positively fun every time, to own and hear.

I have some added ideas, but I will have to discuss these with Dennis, to see if we both agree, before suggesting anything - on line here on HFV. I would love in India to coordinate with someone like Sadik, so he can gain some direct experience with such a non-bookshelf efficient speaker.

It is certainly NOT impossible to get ALTEC 416B or 515B woofers, 802D high frequency drivers, and 811B horns today. These come up on eBay, several auctions at a time, every week.
GPA, at a higher cost, offers them new, often slightly improved. today.

My crossover mod is KISS - to use NO CROSSOVER on the woofer, run it direct full range. It then exhibits the BEST possible in dynamics, and timbres / tone - TRUE to the musical instruments'.

Simply make a home made 12 dB Butterworth network for the tweeter. Use a GTO cap for knife-edge pin point high frequency transient response. Also, use about 5 to 8 paralleled caps, to EQ the 802 speakers' subjective perceived response, and get the two way's top end responding on top...... with all the highs you ever want.

The highs START with the amps multiple bypassing execution, of EVERY cap in the amplifier. That will entail three to seven paralleled film caps, by ear selected, quality caps, in every amplifier " C " location. Dennis and I will not listen to an amplifier and two way speaker, unless it has a GREAT top end response. Easy to do. The wire MUST be that Mil Spec formula, I have outlined here on HFV many times. Nothing yet has beaten it, to date, in our experience. Surplus priced Military wire. LOL.

On A7's, we use 811B Horns, and not 500 HZ horns ( A7-8 ...... not A7-5 ) . Why?? The A7-8 is more usable than an A7-5, especially in a smaller listening room HOME environment. An ALTEC 800 Hz. Horn will play the top end better in a two way, than any 500 Hz mouth size. The 1 inch throat ALTEC 802 will play higher than the lovely 1.4 inch throat sized 288 ALTEC driver.

Note, the 288 or 299 larger compression tweeters are PERFECT and lower in distortion, smoother, and virtually perfect to 13 kHZ. But then, I want the extreme highs, while remaining in a two way speaker configuration, not a three way.

Ask questions !!

ALL of this is to my best direct understanding and IMHO.

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Here ...........


Data correction, thread's Post #1 :

Herb Reichert's 300B Flesh and Blood was in Sound Practices in about 1993 or 1994. We were each building our triode amps in the early to mid 1980s.
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Everything matters. High frequency response starts with every capacitor bank in the tube audio amp. If the amp can't intrinsically play great, linear highs, how can the speaker do so ??

2nd warning on trolling

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Everything matters. High frequency response starts with every capacitor bank in the tube audio amp. If the amp can't intrinsically play great, linear highs, how can the speaker do so ??

Your assertion that loudspeaker wires of opposite polarity that touch each other anywhere "kills highs" is inconsistent with and contradicts several decades of well known and well established principles in physics, mathematics and engineering. Additionally, to the best of my knowledge, no measurements that support your assertion. have ever been published.

To be appropriate with my ALTEC 825 VOTT A7-8 posting in this thread, I would like HFV / Indian audio enthusiasts to watch this interview with Herbie Reichert. and Steve G. It is highly accurate - takes 21 minutes.

They are discussing the A7 VOTT listening experience, ( when well set-up ). How it is different than all other speakers. And how we two guys both intuitively know this A7 design is a HUGE winner !!

Herb discussed Frank Sinatra standing slightly in front of the speaker, right in the middle of the listening room. Also, the Orchestra being spread across his room, full sized as placed across the original Concert Hall.

I hear all this too, and more, and love it.

I got my VOTTs home in 2016. ( Thanks Randy !!! )

Herb in New York, and local friend Randy in my area, both happen to live in retired Firehouses. I live in a small MidWest apartment, and my listening room is only 12.5 feet by 15.5 feet. Presently my A7-8s are paired with the best performing tube amp I know of.

Please do enjoy the Reichert video above.

It is all SO unique, and ......... all so true.

Audio Note ( UK ) had a KIT diy 300B offering - actually as early as in 1979. I built one for classic LP reviewer Neil Levenson that year. Neil asked me build his amp with 2A3s,...... and that was good.

Herb and I probably fondly- remember today the Fair Radio Sales sourced ESPEY 3 HY Power Supply chokes I had him get.... 24 Ohms DCR. $6.00 each. For his Flesh and Blood build. I use wo six Ohm chokes these years.


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