Altec 32A, 32C, Emilar EH1210, EH800, EH500 and Faital Pro STH100

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This is a cumulative report on horns I listened to and tested from May 2016 until the end of 2017. All the tests were done through the mono hifi rig using the above Altec 802 compression driver fitted with a GPA 34852 diaphragm + an Altec 414A in a repurposed Altec 861 cabinet running in full-range mode tied together by a 6dB/octave high pass crossover/EQ hinged at 2500 Hz. 

Altec 32A and 32C

Altec 32A (top)
Altec 32C (bottom)

 The Altec 32A (metal) and 32C (plastic with ribs) horns are lineal descendants of the Western Electric 32A horn as found in the WE753 speaker system. I've had the plastic 32C since '09 and lived with the metal 32A for over a year and can say that these are the most sophisticated native 1" horns I've heard and owned to date.

Altec 32A

Altec 32A

Altec 32A + 802 + 414A

Altec 32C

Altec 32C

Altec 32C + 802 + 414A

Metal or plastic? 

It's ironic that the later plastic 32C sounds more vintage than the earlier metal 32A. Definitely, the longer throat of the earlier 32A and the type of material used for construction influence the sound. But in what capacity, I cannot surely define. The iPhone RTA results reinforce the cooler and more modern sound I hear from the metal 32A versus the warmer and sweeter plastic 32C.

The magnitude of difference is not great. Similar to the 20275 vs. 34852 Altec 1" aluminum diaphragms - distinct enough not to be used as a stereo pair but still excellent performers in their own right. However, those who are expecting a front-row presentation may find both these horns too laid back.

Watch out for roughly finished throat edges in the 32A which are detrimental to performance. So far all the plastic 32Cs I've seen have very smooth throats.

Emilar 

As soon as I landed in the US in May 2016, I tried to collect the Emilar horns talked up by Joe Roberts in his war against the devil's trumpets before they became unaffordable. 😉

EH1210

Emilar EH1210

Emilar EH1210 + 802 + 414A

This wasn't recommended by J-Rob but it was cheap enough to try. The EH1210 has the most extended high frequency response according to the iPhone RTA but subjectively it was the least refined sounding horn in this group. I think one can do much better with some modern offerings, see the last entry below. 

Emilar "Bowtie" EH800 and EH500

Emilar EH500 (left) + Emilar "Bowtie" EH800 (right)

WARNING: these two Emilar horns are heavy cast jobs, doing the audiophile knuckle test can result in serious injury! 😃

EH800

Emilar "Bowtie" EH800 

EH800 + 802 + 414A

If you are looking for a modern sounding horn with a more forward presentation but without the shout and distortion of the Altec 811, then this is the horn for you. Exciting sound but guaranteed not to make your ears bleed. 

I think the low end cut-off at 800 Hz spec is a bit optimistic. For maximum satisfaction start around 1200 Hz and work upwards.

EH500

EH500

EH500 + 802 + 414A

This is a native 2" horn with a finely machined 1" - 2" throat adaptor. Once again I find the 500 Hz cut-off an overestimation for a horn of this size. I'd start crossing around 900 Hz and up. 

My ears do not agree with the iPhone RTA. I found this horn to be mellower than the EH800 "Bowtie." The tonal balance of the EH500 is somewhere in between the Altec 32A/B/C and the EH800.

EH500 in Large Format Mode

EH500 sans adaptor + Renkus-Heinz SSD3301

With the JEL N1600 XO in tow, I removed the 1"-2" throat adapter and bolted the 2" exit Renkus-Heinz SSD3301 directly to the horn to sample large format tones. I got juicy mids and smooth highs from this combo.

Late addition:

Faital Pro STH100

Faital Pro STH100

I wanted to sample what can be had off the shelf at Parts Express for under $100 and ordered a pair of these small aluminum tractrix horns by Faital Pro.

STH100 + 802 + 414A*

*RTA was done at a later date in another location,
hence the difference in low frequency response 

With the Altec 414A running full range and the STH100/802 combo crossed at approximately 2500 Hz, I got very clean (if a bit dry) high frequency harmonic augmentation with no nastiness at all. To my ears, this tractrix horn is preferable to the EH1210.

CODA

For the past 4 years, I've been blogging about horns and compression drivers. Justifiably, the horn/driver combo seasons the speaker system's sonic flavor. However, these components only cover the upper three octaves of the audio band (mostly harmonic overtones). I would be remiss if I didn't stress the greater importance of the Altec 12" 414 woofer/midrange because it is tasked to reproduce most, if not all, of the fundamental notes in music from 30 Hz to 4000 Hz. That's seven octaves, practically the frequency range of a piano.  

I've been trying, but so far haven't found alternative 15" or 12" woofers that play the midrange as well as the Altec 414. The good news is, Bill Hanuschak of Great Plains Audio told me last year that they still re-cone 414s and their product page lists an Alnico 414-8B(16B). 

Altec small format diaphragms: Aluminum vs. Symbiotik

I've been playing around with Altec drivers for almost 20 years and have only listened to aluminum diaphragms until now.

Altec Aluminum Diaphragms

Altec 20275
Aluminum voice coil
DCR = 9 ohms

The 16 ohm Altec 20275 is the original diaphragm fitted to my cherished green hammertone 802D. This is the Altec diaphragm I am most familiar with and to my ears its tonal balance favors the midrange more than the later 34852, which is known for better high frequency extension.

I speculate that late 40s to 50s wrinkle charcoal gray/brown and late 50s to 60s hammertone green 802s, 804As and 806As command premium prices IF they are fitted with original and intact 20275s, which are now unobtainium. By early to late 70s, black 802s and 806s were fitted with either the 16 ohm 34852 or the 8 ohm 34647.

Altec 34852
Copper Clad Aluminum Wire voice coil
DCR = 12.5 ohms

My Altec 605B Duplex should have been originally equipped with a 20275 but by the time I acquired it, this 34852 was already fitted. Maybe that's why I still got it cheap ;)

As previously noted in my 605B experiments, I hear a significant sonic difference between a 34852 and a 20275, so much so that I cannot recommend their use as a stereo pair. Jeff Markwart has more 20275 vs. 34852 info if you scroll down to the bottom of this page. 

GPA 34852
Copper voice coil
DCR = 11.5 ohms

AFAIK, Great Plains Audio is the only source for Altec diaphragms made to original Altec specifications. Even if they have a website, they prefer to do business the old fashioned way. I always call Bill Hanuschak to place an order and never had problems.

I haven't had a chance to compare this GPA 34852 to the Altec 34852 because the 605B Duplex was left behind in the attic;( But there's no doubt that this GPA is the real thing - very dynamic, with clean and clear harmonic overtones up the wazoo!

Altec Clone

Chinese Aluminum Diaphragm Clone
Copper voice coil
DCR = 11.9 ohms

For kicks, I made an offer to one of the Chinese vendors on eBay and got this pair of 16 ohm diaphragms for about $24/pair, shipped. These clones will tide you over in a pinch. However, even a casual comparison to an Altec original or GPA diaphragm revealed smeared harmonic overtones and compressed dynamics.

Spot the fake

Left picture (clockwise from left) - older version Altec diaphragms used screw terminals on a raised platform, later Altecs and GPAs have tabs, Chinese clones do not have a raised platform for the screw terminals. 

Right picture - The raised platform in the Altec uses tapped machine screws whereas in the Chinese copy the screws are self-tapping.

Altec Symbiotik

I recently acquired a couple of unloved 70s era 802 and 808 drivers, some fitted with Symbiotiks. 

Two abused Altec diaphragms:
Symbiotik on the left and aluminum on the right

The Symbiotik was Altec's initial response to the 60s demand for a higher power handling diaphragm. As pictured above, due to the rigidity of the aluminum suspension, it can shatter when overdriven. I can only surmise that the Symbiotik  diaphragm, which uses a polyimide/mylar type suspension, evolved from a research and development project at LTV by John Hilliard and Jonas Renkus.

Early + Later Symbiotik diaphragms

In early Symbiotiks, the abrupt 90 degree angle voice coil termination (left) also caused failures in the field due to metal fatigue. I repaired this early Symbiotik by carefully flowing solder between the broken ends with a low temperature soldering iron. This issue was rectified in later production Symbiotiks (right). 

Uncovered: Altec > Emilar

Top = early Emilar with brown mylar suspension
Bottom left = later Emilar with gray mylar suspension
Bottom right = Altec Symbiotik

I have written favorably about Emilar and Renkus-Heinz compression drivers, and noted that their extreme top end was a bit reticent compared to Altec drivers with aluminum diaphragms. Let's see how the earlier Symbiotik technology stacks up.

Top = later Altec Symbiotik with tabs and
improved termination
DCR = 6.7 ohms
Bottom = early Altec Symbiotik with
screw terminals
DCR = 7.5 ohms

In retrospect, Altec aficionados may have been hasty and/or unkind in their initial reception of the Symbiotik. Even if the Symbiotik rolls off earlier than its aluminum brethren, it still reproduces proper harmonic overtones. It sounds very sweet, airy and open, with none of the smearing and compression I hear from the Asian clones. A Symbiotik equipped 802/808 sounds more organic than its descendants from Emilar and Renkus-Heinz. To my ears, the Symbiotic diaphragm has a niche in Hi-Fi and may well be the antidote to those who find the aluminum diaphragm a bit aggressive. 

Unfortunately, there are no modern replacements for Symbiotik diaphragms. You'll have to find original units that did not suffer catastrophic meltdowns. Although it's just a hunch, the Radian replacement diaphragm for Altecs should have Symbiotik DNA because of the Emilar/Plus One connection.

Octave RTA by Onyx

Since affordable audio measurement apps have become available, I got this $5 app for my iPhone as suggested by my buddy J-Rob.

Test set-up

The Altec 414A housed in a 3.5 cu. ft. repurposed Madrid (861) bass-reflex cabinet is driven full-range, J-Rob style, while the Altec 32A metal horn + driver combo is protected by the crossover + EQ below.

Crossover + EQ

I was quite surprised to see pretty decent RTA results since I've been building/tweaking crossovers for over 20 years without a computer simulation program or an RTA.

Altec 802-8D + GPA 34852

Altec 808-8A + Chinese 16 ohm diaphragm

Altec 808-8A + Symbiotic

Emilar EA175-16 (alnico)

Emilar EC175-8 (ferrite)

These graphs pretty much represent how these driver/diaphragm combinations perform except the Chinese clone which looked good but sounded rolled off, compressed and smeared as mentioned above. Unlike human ears, an RTA will measure sound waves but will not discern unmusical harmonic overtones. Even my wife thought the Chinese diaphragm sounded muffled. Although she argues that if I can afford only a $12 diaphragm, I better be happy with it ;(

It goes to show that it is much easier to satisfy audio measuring equipment than human ears. 

Update

Check out HifiTown's Altec 808-8A video! 

1" compression drivers - Emilar, Renkus-Heinz and Beyma

Is there life after Altec?

My first encounter with Emilar and Renkus-Heinz was in a discussion at the Lansing Heritage forum in 2006. Apparently, Jonas Renkus was a principal at both companies in the 70s and 80s. Prior to co-founding these companies, he worked under John Hilliard at Altec Lansing and followed him at Ling Temco Vought (LTV) where they developed a new compression driver with a polyimide suspension aluminum diaphragm. A paper on this research was submitted to the Journal of the Audio Engineering Society in 1966. This association piqued my interest, which triggered my search for affordable Emilar and Renkus-Heinz drivers.

Soon after I arrived in Manila, I became friends with artisanal speaker craftsman Lin Gomez. He is the go to person for Altec, JBL, Jensen, Western Electric or any vintage driver that needs restoration. His company used to be the official Beyma importer. During his closeout sale of Beyma inventory, among those I purchased was a pair of Beyma CP380M.

For the past couple of years, I've been playing with these drivers in the attic mounted either on the Altec 811, RCF H3709 and Altec 32C. But all of my recent critical listening was done through the mono rig driving one side of the Altec 2-way using the following crossover set up.

Crossover

3khz @ 6dB/octave high pass + HF ATT/EQ
for 16 ohm drivers

To keep things simple, critical listening tests were done with the Altec 414A full range and the above crossover was used for the Altec 802D and Beyma CP380M (both 16 ohms) cutting in @ ~ 3000 hz with a 6dB/octave slope.

3khz @ 6dB/octave high-pass + HF ATT/EQ
for 8 ohm drivers

For the 8 ohm compression drivers the above crossover was used and the 414A running full range. The 8 ohm L-pad substituted in place of a 25 or 30 ohm wire wound pot works just as well.

Splitting hairs

For all intents and purposes, these drivers were designed for similar real world applications. Since each manufacturer had their own set of measurement parameters, I deemed the inclusion of driver specifications inconsequential. Anyway, I noted that the minor differences in driver efficiency were well within the shelving range of the attenuator on both crossovers.

My main objective was simply to find out how each compression driver attached to the Altec 32C horn blends with the outstanding midrange performance of the Altec 414A woofer loaded inside the 614 bass reflex cabinet. In an ideal world, the blend should be seamless, with the horn/driver combo just filling in the missing upper frequency harmonic overtones not within the reach of the woofer.

Altec 802D
16 ohm original aluminum diaphragm
Alnico magnet

The 802D has been a musical companion for almost 20 years, so I know it very well. Attached to the 32C horn and playing duets with the 414A, they produce a harmonically rich and luscious midrange along with high frequencies that are silky smooth and extended. To my biased ears, it would be difficult to equal the 32C/802D/414A/614/JELN1600CXO quintet, short of a WE757A ;)

Emilar EC175-8
8 ohm original diaphragm
Ferrite magnet

My first impression of the EC175-8 which lingered all throughout my listening test, was a rich midrange reminiscent of the 802D. Perhaps this was due to its rather subtle presentation of high frequencies which are there, yet not stealing the limelight from the midrange. It's worth noting that this driver has a similar long throat design as the 802D. 

Renkus-Heinz SSD 1800-8
8 ohm original diaphragm
Ferrite magnet

The SSD 1800-8 + 414A was also a coherent combination. But the tonal balance was the antithesis of the EC175-8. The midrange sounded a bit leaner due to more prominent high frequencies. This driver has a short throat/pancake design like the 902-8B below. I wonder if the short throat configuration tends to enhance high frequencies?

Caveat: Based on my internet research, there are no original replacement diaphragms currently manufactured for Renkus-Heinz drivers.

Altec 902-8B
8 ohm original diaphragm
Ferrite magnet

To make things more interesting I borrowed a pair of Altec 902-8B cherished by my buddy Joel. The sound of this driver is similar to the 802D with the midrange not quite as lush but still vivid and involving. Since it had the best high frequency extension and transient response, the sound was invigorating. 

Top left: Beyma 8 AG/N 8" fullrange
Top right: Beyma SM115 15" woofer
Bottom left: Beyma CP380M
Bottom right: OB experiment ca. '09

In early 2009 I experimented with the CP380M + 32C coupled to the 15" Beyma SM115 woofer in an open baffle. I was actually quite impressed by the potential of this combination which was the reason I bought them.

Beyma CP380M
16 ohm polyester diaphragm
Ferrite magnet

However, in the context of this survey, the CP380M did not fare as well as the other drivers. Although the sound was quite pleasant with good high frequency extension, I was constantly aware of a transition between the 414A and the horn. Perhaps it was really voiced for a Beyma woofer?

Coda

The Emilar EC175-8 and Renkus-Heinz SSD 1800-8 have their virtues and omissions. If their virtues were combined, then we have a true Altec alternative. Yet despite their minor flaws, mounted on the Altec 32B horn, both easily coalesced with the Altec 414A woofer which corroborated their genetic heritage. If I didn't have the 802D, I could have easily lived with either the EC175-8 or SSD 1800-8 with a slight preference for the EC175-8 just because I'm a midrange hedonist;) 

With regards to the Altec 802D vs. Altec 902-8B, it boils down to a matter of taste as well as availability and affordability. As for the Beyma, when time permits, I will rehash the OB/SM115 + CP380M/horn experiment and post my findings;)

Happy listening!

Parts Express 1" Horns and Waveguide Buy Out Specials

July was a hectic month - four 4th of July concerts with Harrisburg Symphony + two concerts at the Shippensburg Summer Music Festival. It was a welcome respite to receive an invitation from Joe Roberts to meet him at his mom's house in South Philly after I was done with all those gigs.

Leica II + Summitar 50mm f2
Ilford FP4+ in Kodak HC110

He gave me a tour of his old neighborhood, pointing out areas where he started his archeological expeditions as a kid. For lunch we stopped by this hoagie shop for really great Philly cheesesteaks. 

It was very interesting to listen to his recollection of South Philly as a kid, and how the area continues to evolve as people of different ethnicities, socio-economic and cultural backgrounds come and go.  

Before I-95 swarmed with rush hour traffic, I had to head back north with this box filled with horns from Joe. I didn't envision writing about 1" format horns again since I posted this blog entry last February. But after spotting the Azzolina KS12024s, it was hard to pass up this opportunity. Meanwhile, this post will focus only on the Parts Express horns.

Testing

I used Altec 802 1" compression drivers fitted with GPA 34852 16 ohm diaphragms mounted on top of Altec 614 cabinets loaded with 414A woofers (running full range) with the crossover below tying things together. All listening was done in stereo in the man cave.

High pass @ ~ 2500 Hz

I used these two horns as references and for the first time I was able to convince my wife, Tish, to indulge me with her sonic impressions.

Altec 32C

Tish and I love this descendant of the old school WE32A horn. She describes it as sublime.😉 

Emilar EH500

This is my favorite horn from the 70s. It was designed by Jonas Renkus who worked with John Hilliard at Altec Lansing. 

Parts Express Specials 

Round 1 

(deeper/longer exit Altec 802)

Parts Express: 299-2303

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Altec 802

There is an ongoing thread at Hi-Fi Haven about cheap horns where this particular horn/waveguide was mentioned. Its specs are listed as a 600 Hz, 10" x 14" exponential horn waveguide with a 90° H x 40° H dispersion pattern, made out of heavy ABS plastic. Price: $12.88/ea.

Sound

Tish: Not bad, but not as lush sounding as the Altec 32C. It will eventually hurt my ears. 

JE: Tonal balance is reminiscent of the Emilar EH500. However the sound gets congested with complex musical passages (especially at higher SPLs) which can cause fatigue during long-term listening.

Community UC-1
part# 299-522
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Altec 802

Dimensions: 10 3/8" W x 5 7/8" H x 6" D

Dispersion: 90°H x 40°V

Cut off frequency: 2000 Hz

Price: $4.48/each

 I had to DIY adapter plates to mount the 802 drivers.

Sound

Tish: Harsh and shouty👎👎👎

JE: Sounds better disconnected. What were you thinking J-Rob???🤣

Faital Pro revisited

Faital Pro STH100 + Altec 802

Dispersion: 80° H x 70° V

Dimensions: 7" W x 4 3/4" H x 3 5/8" D

Material: Metal

Price: $67/each!!!

Sound

Tish: I like this best among the three - easier on the ears compared to the other two, but not even close to the 32C.

JE: I am less impressed this time around despite the clean sound. It has less congestion, harshness and tizz than the B52/QSC clone 299-2303. But the presentation still falls far short of what I hear live. With the recent price increase, I can no longer recommend this unit.

!!!STOP PRESS!!!

Pasted below is a post by @ARX in this Hi-Fi Haven thread

Gentlemen,

Very interesting experiments with different types of horns and waveguides (the B-52 1" QSC clone is a waveguide), both vintage and more recent designs.

The 802D with the B-52 1" might not be an optimal combination. The original QSC PL-000446GP was designed by Mark Engebretson, former VP of Engineering at QSC, to be used with Celestion compression drivers. From the many measurements available online it's obvious this waveguide performs best with modern, pancake style compression drivers, that have a short exit instead of the deeper/longer exit of most vintage drivers like Emilar, Altec etc.

You might try B&C, Celestion, Beyma, BMS and similar 1" drivers.

There's much more to the underlying physics, but it should come as no surprise the EH-500 and Altec 32A/B do indeed sound wonderful with the vintage drivers. The gradual expansion of the wavefront from driver diaphragm to horn mouth is (almost) perfect. On the other hand, a pancake driver behind an oldskool horn, with a few exceptions, is unlikely to yield spectacular results.

Altec 802 (left) + Renkus-Heinz SSD1400-8 (right) 

The only pancake type (short/fast exit) 1" compression driver I have on hand is a pair of Renkus-Heinz SSD1400-8. This is a smaller magnet version of the SSD1800, which I got to know quite well in the attic. Hence, I had a gut feel that I was going to learn something important from @ARX. So the SSD1400-8 was pressed into service for another round of listening.

Round 2 

(short/fast exit Renkus-Heinz SSD1400-8)

Parts Express: 299-2303

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Renkus-Heinz SSD1400-8

 According to ARX's post above, this is a clone of the QSC waveguide, which was designed to be paired with a B&C DE250 compression driver in the Econo-wave project at Audiokarma.

With the short exit R-H SSD1400-8 mounted, this waveguide was transformed. Although not quite on the same level, the sound now more closely resembles the Altec 802/Emilar EH500 pairing. The congestion I heard in Round 1 is gone with a substantial gain in midrange lucidity. Long term listening fatigue is no longer an issue since the sound has opened up with a nice airiness to it.  👍👍👍

Community UC-1

part# 299-522

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Renkus-Heinz SSD1400-8

This horn became a lot more listenable with the SSD1400-8 mounted behind it. It sounded even better crossed over @ 5kHz. Detailed and airy but the midrange isn't quite as vivid as the B52/QSC clone/299-2303. For the record, Community compression drivers are also short/fast exit (pancake) designs.

Faital Pro STH100 

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Renkus-Heinz SSD1400-8

Sadly, this tractrix horn became unlistenable with the SSD1400-8. Probably a mis-match? Faital Pro 1" compression drivers look more like old school Altec 802s and Emilar EA/EC175.

Parts Express Horn Wrap

Two important lessons learned:

1. Thank you very much @ARX for enlightening me! Otherwise, I would have joined the ranks of fake news bloggers. 🤣

2. My preference for matching harmonically rich-sounding components will always entail a classic pairing of units that are long out of production and are becoming more unaffordable as the years go by...😞