Altec 605A versus 605B

**joyspring** · January 11th, 2006, 04:23 AM

Steve:

Why not contact a local speaker hobbyist in your area and actually _measure_ the Thiele-Small parameters of your 605s (once you've made a purchase, that is)? It actually matters very little whether the 605 is an `A' or a `B'.

The likelihood of any 605s your purchased having been reconed is quite high; likewise, the likelihood of any _consistency_ of T-S parameters between 605s is very low...

For reference, you may want to consult the GPA T-S parameters URL:

Altec T-S parameters (GPA)

However, it's highly improbable that any reconed 605 will match those specs -- in my experience, GPA recone kits are not even close.

If this is a long-term proposition (rather than a hobbyist experiment), I recommend that you go ahead and purchase a pair of 605s, either `A' or `B'.

Then have them serviced from the ground up with new cones and diaphragms and fully realigned and remagnetised motors; GPA can do this and it is a sound long-term investment.

And then have a `normal' loudspeaker hobbyist/enthusiast (that is, not a vacuum tube / vintage freak living in a retro-dream-world of phonograph LPs, Scotch 111 analogue tape and mono optical soundtracks) accurately measure the 605s; many have CLIO/LMS/MLSSA or at the very least the requisite function generator, frequency counter and AC millivolt meter to yield accurate T-S parameter and impedance measurements.

At that point, you can decide the alignment and performance specs of the enclosure.

I recommend `sealed' second-order, maximally flat which will likely yield of -3 dB of 70 - 90 Hz and a 3 - 6 ft^3 enclosure volume. Sealed enclosures are much more tolerant to changes in T-S parameters than tuned vented (reflex) alignments and hence will be less apt to yield surprises after a subsequent recone.

Use an ancillary powered subwoofer with the lot for the lower two octaves.

Realise that you will have very little output above 10 kHz and will also have poor power response. Your `sweet spot' will be very narrow and overall room response quite coloured though the stereophonic imaging will be excellent.

Proper loudspeaker / room interface and in particular mitigating early reflections will then become much more critical than with modern, even-power-response system designs. Here's a great site from a recording engineer who is not an idiot (which is definitely a minority nowadays):

Acoustic Treatment and Design for Recording Studios and Listening Rooms

Ethan Winer also has an excellent article dispelling popular audio myths, many of which are prevalent and unfortunately propagated on this forum:

Dispelling Popular Audio Myths

Good luck,
BobR

**joyspring** · January 11th, 2006, 06:47 PM

bfish:

and am also one that likes to separate the myths from the facts, I don't beleive in 'blindly' precluding the use of any technology from ANY era for that reason alone.

The last URL in my previous post links to an article that dispells many very common audio myths.

Here's another article (in PDF) from The Audio Critic, an EXCELLENT consumer audio publication that a former colleague (and former Altec Anaheim electroacoustic engineer) recently turned me on to:

The Ten Biggest Lies in Audio

You'll notice a few trends:

<ul>[*]first, engineers are skeptics and demand empirical evidence to back up wild assertions.[*]secondly, every competent audio authority (that is, electroacoustic, electrical engineers, material scientists, physicists, mathematicians, etc.) counter the prevailing audio mythology, including: subjective audio testing, the superiority of vacuum tubes/analogue tape/phonographs, etc.[*]newer audio technology is superior to older audio technology[*]Those who assert that older technology is superior often
<ul>[*]have never used or have little experience with older technology[*]have never used or have little experience with newer technology[/list][/list]

As for `blindly' precluding the use of any technology from ANY era, I'll state that I have extensively used/designed audio technology from the late 1970s up to 1997, and have resumed doing professional audio work from 2002 onwards.

I assert that nearly every audio technology today is superior by several orders of magnitude than it was in the late 1970s: digital recording/playback, signal processing and transducer technology (particularly in terms of materials) all have improved marked since.

Okay, a lot of forum members are probably wondering about my previous advocacy for Altec 604/605 and UREI monitors...

Well, I have an immense investment in these monitors (I purchase my original two sets of 811 and 811As new) and human nature being what it is, I could not admit that these monitors were superceded by newer technology.

Truth is, they were and I finally have come to terms with this. I do still use the UREIs for professional work but depend on a newer set of Mackie HR824 powered control room monitors for critical work now... they are infinitely superior, as are many inexpensive, contemporary recording monitors nowadays.

As an aside, being the engineering director and audio professor for a film department at a four-year university, I was charged with replacing aging but meticulously maintained Altec VOTTs (210 + dual 515 + 288 + 1505 multicell) with a modern JBL 4675 + sub THX cinema system in our university theatre.

Initially, I had my reservations, being an hard-nosed Altec advocate. However, during the retrofit, I came to realise that the modern system is far superior: in frequency response (especially at bandwidth extremes), distortion, intelligibility, dispersion/coverage and maximum sound pressure level.

Yes, the JBLs did require 4x electrical input power to achieve the same SPL, but the full-bandwidth distortion was an order of magnitude lower, even at full tilt. Both students and visiting industry professionals immediately noted the improvement.

I did try to duplicate the sub-harmonic anomalies that Jim D always refers to in JBL 2" titanium-diaphragm compression drivers but FFT did not bear this out.

Better thermal management, better materials science, better magnetic circuit optimisation, better horn technology. Things improve as time goes on; you simply cannot avert that.

Is it possible you suffer from "reverse blind faith"?

No, because I don't believe in `faith'; I believe in objective, empirical data. And the empirical data clearly shows that modern technology has wider bandwidth, lower distortion/noise and more waveform accuracy.

That is the crux of science and engineering, even audio engineering.

As Floyd Toole (senior electroacoustic engineer at JBL/Harmon) quipped, audio engineering is `science in the service of art'.

Until the masters for ALL my favorite recordings have been faithfully copied without enhancement (read; as the artist intended it to sound) to digital media, I'll keep playing them on the only means available. I have A/D'd much of my vynyl, but would need access to the masters to do it all right.

Apart from bad aesthetic editing decisions made by some of the reissue producers, `faithful', `without enhancement' etc. ignores the limitations of the original analogue media.

Firstly, analogue tape has a limited shelf life and the audio quality of the recorded media suffers over time. The magnetic flux of the oxide diminishes (along with audio HF information), noise significantly increases, tape binders (glue) that hold the oxide to the backing harden and acetate backing becomes exceptionally brittle.

Yes, many digital reissues have worse audio quality than the original analogue pressings, but again, this is not due to digital technology; this is strictly an analogue limitation.

Secondly, the aesthetic EQ and dynamics decisions made at the mastering process of a vinyl LP also compromise audio quality: everything is rolled off below 40 Hz, everything below ~100 Hz is mono-ized to improve stylus tracking, MF and HF EQ is rather arbitrary since consumer playback cartridges/styli/phono preamps all yield differing frequency response depending on a myriad of variables including cartridge output impedance, preamp input impedance, etc. (the audio redbook CD changed all that, thank goodness!).

So yes, `enhancement' is a consequence of the original media. Even if you had access to the masters, you would still not be able to `do it all right'.

BTW, a large part of my personal audio business is transfers from a few defunct analogue formats (LP/78s, 1/4" analogue tape) to digital; my major clients include universities and two large ethnomusicology archives. I have two meticulously-maintained 1/4" half-track analogue recorders, a Nagra 4.2 and IV-S and two professional transcription turntables with AT tonearms. So I'd say I know `a bit' about analogue technology and its limitations.

Again, in a word, vinyl LPs **** .

If forced to listen only to the OTC digital media available today, I'd soon be looking for an icepick to poke my eardrums out with.

Why? Some of today's recordings are the best ever made! The resolution of 24-bit digital is so fine and the noise floor so low that you can actually hear HVAC/traffic noise, musicians' breathing, turning pages, etc., all stuff that was previously buried under turntable rumble and surface noise.

My favourites include contemporary Rudy Van Gelder (an early adopter of digital), Tom Jung (DMP Records) and any classical recorded by John Eargle (yes, from JBL/Harmon Int'l) on Delos. BTW, all are proponents of digital recording.

I'm not so happy about the apparent success of SACD over DVD-A but it's still an improvement over CD. And all are an immense improvement over the vinyl LP.

Believe-it-or-not, many "vintage freaks" have capable measuring and test equipment, and are also proficient in its' use.

This is probably the only thing I will concede to ;-)

BobR

**bfish** · January 11th, 2006, 08:08 PM

Applause!

Your reply is logical, understandable, and far more along the lines of what we laypersons would expect to hear from a professional such as yourself, than the previous rash comment I quoted, (read; leave the dissing to us unsophisticated goobs. It doesn't become you, and detracts greatly from your message).

While not wanting to drag this thread into new territory, I do feel that "science in the service of art" occasionally falls short of its' goal, by strictly adhering to 'textbook' empiritical data, and overlooking the most basic intent of the artist.....that being the emotive enjoyment of their works by the listener. Even Mr. Winer admits to preferring some of the less-than-perfect older tech, ITR.

Since most of us can't have a state-of-the-art studio in our living rooms for various reasons, and are now unable to look forward to the release of new Altec products (as we know them), we're forced to either make the best of what we have, or abandon Altec entirely, something many of us are too old (and stubborn) to be willing to do. I, for one, intend to die with a smile on my face.......

Hope I didn't offend you, we welcome your input, and are glad to have you back! I just couldn't resist "poking the pig" a little, just to hear it squeal.

Brad

**joyspring** · January 12th, 2006, 07:06 AM

bfish:

While not wanting to drag this thread into new territory, I do feel that "science in the service of art" occasionally falls short of its' goal, by strictly adhering to 'textbook' empiritical data, and overlooking the most basic intent of the artist.....that being the emotive enjoyment of their works by the listener. Even Mr. Winer admits to preferring some of the less-than-perfect older tech, ITR.

On the contrary, `science in the service of art' clarifies design goals and separates and distinguishes between the disparate roles of creating the art and reproducing it.

As I've mentioned in numerous previous posts, the creativity ENDS at the mixing and subsequent mastering phase of record production. It is then that the mastering engineer will perform final EQ and dynamics processing to fit any limitation of the media (CD, LP, cassette, etc.) and to make any last possible improvements to the product.

Before mastering, during tracking and mixing, the artists (musicians) and recording engineers will use a wide variety of instruments, room acoustics, microphones/transducers, signal processors, recording medium to achieve the desired sound, timbre, whatever... some of the equipment may even be outfitted with vacuum tubes producing characteristic even-order harmonic distortion!

However, it is assumed (and desired) that the monitoring environment and the end-user (yes, that means YOU, the consumer) has PLAYBACK equipment that:

<ul>[*]has flat frequency response[*]has low distortion[*]has wide dynamic range and low noise floor[*]has excellent waveform integrity; that is, IMPARTS NO SOUND OF ITS OWN, including
<ul>[*]`tube warmth'[*]`organic analogue airiness'[*]other audiophile silliness[/list][/list]

You may have missed this distinction between creation of media and playback of media in Ethan Winer's Dispelling Popular Audio Myths article but he was quite clear in making this point:

"Studio monitor amplifiers should never have a "sound;" if they do, they are in error."

That also applies equally towards the end-user's playback equipment as well.

Hopefully those who pine for changing the (collective) artists' intent by `adding tube warmth', or other audiophile bull**** will digest all this... attempting to change the sound during playback really amounts to a slap in the face to the mix and mastering engineers and all those involved in the creative process as well.

Since most of us can't have a state-of-the-art studio in our living rooms for various reasons, and are now unable to look forward to the release of new Altec products (as we know them), we're forced to either make the best of what we have, or abandon Altec entirely, something many of us are too old (and stubborn) to be willing to do. I, for one, intend to die with a smile on my face.......

It's important to note that technology improves as time goes on; it is an engineer's goal to provide better quality at lower cost.

Today's audio equipment (above the lowest price point of course) provides FAR BETTER PERFORMANCE than even the best state-of-the-art equipment of the 1950s and 1960s, hands down.

It's nice to be nostalgic about Big Iron from the halcyon days of hi-fi (and I do admit I often forget this is an advocacy site for vintage Altec) but it's also important to realise that this technology -- despite the high price, precision manufacturing, expensive materials and physical massiveness -- has been eclipsed by modern, inexpensive equipment that benefits from improved, computer-optimised design, better materials, better understanding of psychoacoustics, digital technologies, etc.

The engineers have done their job, building upon the research of their predecessors, including those at Altec.

Hope I didn't offend you, we welcome your input, and are glad to have you back! I just couldn't resist "poking the pig" a little, just to hear it squeal.

No offense ever taken; it was fun to `squeal'. My students love it ;-)

BobR

**bfish** · January 12th, 2006, 02:05 PM

Bob,

We're actually in agreement here, I'm just unable to state my position as well as you (I AM a hillbilly that types with one finger, even though I play my pianos, organs, and guitars with all of them). I tried to express this opinion in an old thread;

++++++++++++++++++++++++++++++++++++++++++++++
"My opinion on tubes vs SS is very similar, in that tubes still have the edge for musical instrument amps/effects, while SS (and some newer digital) rules for accurate REproduction. The reason is simple;

To date, ALL AF amps add an element of harmonic distortion to the signal. The TYPE of harmonics is where the difference lies. The HD of a tube amp, while generally at higher levels than SS, is, by nature, pleasing to the human ear, as the individual harmonics are "in tune, musically" with the original signal (think Whitney Houston). This accounts for the "warm, full" descriptors often applied to tube sound. SS HD, on the other hand, is, also by nature, of an order that is dischordant with the original signal (read; sounds nasty, think Edith Bunker).

The other main difference lies in the clipping characteristics of tubes vs SS, but this parameter is of use to musicians only, as listeners should never drive their stereo amps into clipping, no matter what type.

Back in the 50s, musician's gear and home hifi gear all used the same technology (and many of the same parts!). Evolving technology has changed everything, IMO, improving in the field of sound reinforcement and home listening, and, again IMO, taken the new tools for musicians to all-time lows! There's a good reason most of us listen to "old" music, and it's not just nostalgia....."
+++++++++++++++++++++++++++++++++++++++++++++++

Since Altec made (a limited amount) of musician gear, as well as playback gear, and I dabble in both fields, I use this forum to both learn, and share my (limited) knowledge and experience. I've never been able to properly express my feelings about the need for playback systems to 'accurately reproduce all that distortion' near as well as you just did. Thanks!

That said, and in the defense of many fellow members' choice of gear, I feel that those who have chosen the "old" methods of playback for whatever reason, do so more in the spirit of enjoyment of music (which I'll forever promote), than the pursuit of absolute perfection. I hope to never be found guilty of discouraging anyone from enjoying music, no matter how they choose to do so. I believe the difference between "sounds good", and "sounds the best" is actually fairly small to the user, though I also understand the 'need' for engineers' and designers' continuing pursuit of 'perfection'.

When I said I "intend to die with a smile on my face.....", I should have followed up with "even if it's one of ignorant bliss".

Some food for thought; Does a group of teens dancing around a boom box ENJOY the experience any LESS than a group of "audio critics" listening in a well-built studio with their cigars and whine?.....I think not.

**Steve Mac** · January 12th, 2006, 02:59 PM

I think the argument of solid state versus tube technology has failed to address one simple fact:
Both methods for amplifying an audio signal have improved immensely.

**zelgall** · January 12th, 2006, 10:29 PM

Quote from BOBR: "Hopefully those who pine for changing the (collective) artists' intent by `adding tube warmth', or other audiophile bull**** will digest all this... attempting to change the sound during playback really amounts to a slap in the face to the mix and mastering engineers and all those involved in the creative process as well."

If all the mix and mastering engineers all had the same level of quality equipment and ability to both use it correctly as well as hear the difference, us regular folks wouldn't want to change it. Some of them (not all) deserve a slap in the face for ruining good performances with mediocre recordings or mixes. It's the "all properly designed amps sound the same" thing and it just ain't so.

**martyh45** · January 13th, 2006, 12:54 AM

The Majority of recordings available were mixed and mastered using tubes and alnico, the best way to hear what the artist intended is by replicating the playback chain used in the studio.
Regarding all of the tube Vs SS, digital Vs analog, BobR knows full well that all design entails compromise. Simple triode circuits, older speakers with under hung coils and powerful magnets, high speed 1? tape?? all have certain advantages over their more modern counterparts but are deficient in other areas. Setting up a super cable tweek straw man and bashing him might be fun but it is disingenuous. Remember, these recording ?engineers? are the same people that brought you the 25? wide violin by way of the improved recording technique of using fifty freekin three microphones to record sound for two ears

**Carl Bill** · January 13th, 2006, 03:22 AM

After reading the audio myth link, I feel much better knowing that cryogenically treated electrical outlets didn't make the myth list!

I would have been so embarassed. forums

And he didn't mention "directional" speaker or line level cables either, so they MUST do some good. (add cryo treatment to these puppies and they must add 15 horse power to the car stereo!)

forums

All that aside... The old Altec stuff is still the best cost effective path I have at a decent audio system at home. I have been playing with it for 25+ years and I can't even begin to afford anything newer (read: current technology) at anywhere near the cost. However, my old low tech Altec stuff still impresses almost anyone that comes around. There really are not that many folks out there running A7's or Model 19's in their living rooms.

Yes, new JBL or whatever brand is now on top (didn't EAW get bought out by Mackie?), may have the edge, but at what cost?

**Steve Mac** · January 13th, 2006, 04:46 AM

Originally posted by BobR:
bfish:
However, it is assumed (and desired) that the monitoring environment and the end-user (yes, that means YOU, the consumer) has PLAYBACK equipment that:

<ul>[*]has flat frequency response
[*]has low distortion
[*]has wide dynamic range and low noise floor
[*]has excellent waveform integrity; that is, IMPARTS NO SOUND OF ITS OWN, including
<ul> [*]`tube warmth'
[*]`organic analogue airiness'
[*]other audiophile silliness[/list][/list]
BobR

Yeah, forget the Quad ESLs, get yourself a set of Yamaha NS10's.

Thread: Altec 605A versus 605B

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