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AR 2ax vs. Large Advents?


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#1 wilson

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Posted 05 July 2009 - 05:51 PM

Hi Folks, I need s set of speakers to use primarily with a Pioneer sx-1050. While I wait to stumble upon a pair of 3a's at a yard sale,
it seems like I can pick up the 2ax's or large Advents pretty reasonably. Any reason to think that one is significantly better than the other-
or should I just grab the best deal on either?

I realize that I'm asking in the AR forum :rolleyes: - but I had to pick one.


Thanks for your thoughts.

#2 Diamonds&Rust

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Posted 05 July 2009 - 10:36 PM

The 2ax and the Advent have different strengths.

I own 2axs and do not own Advents, I also like the 2ax... --- in the interest of full disclosure.

If I were going to choose one or the other as temporary "main" speakers, I would choose the Advents, not only for their good sound and extended bass, but also because of their tweeter and 2-way design. The 2ax tweeter is *great* so long as it isn't full of rotted foam and still works. I don't think they are as pretty, if that enters the equation.

I'm just saying that if I were to choose something for temporary use that is less likely to present restoration problems, I would choose the Advent.

Bret



Any reason to think that one is significantly better than the other- or should I just grab the best deal on either?

I realize that I'm asking in the AR forum :) - but I had to pick one.


Thanks for your thoughts.



#3 Shacky

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Posted 09 July 2009 - 01:47 AM

I've had original utility Advents, NLA's, 2AX old, 2AX new. I still have the 2AX. Not the Advents. Of course YMMV but to me the AR's just sound richer. I don't like bright speakers so put that into the equation.

I've always heard about great Advent bass. TO me their midrange is what makes them.

#4 joelongwood

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Posted 01 September 2009 - 09:28 PM

I've had original utility Advents, NLA's, 2AX old, 2AX new. I still have the 2AX. Not the Advents. Of course YMMV but to me the AR's just sound richer. I don't like bright speakers so put that into the equation.

I've always heard about great Advent bass. TO me their midrange is what makes them.

Yup, you are correct Shacky....it's the upper midrange that was intentionally (or so I've heard) boosted a tad by Mr. Kloss in order to grab the ears of the listener in the showroom. In comparison, ARs sounded a bit dull. But for long term listening, give me some vintage ARs any day........all day. Although I do enjoy the Advents on occasion. ;)

#5 Steve F

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Posted 02 September 2009 - 05:04 PM

First of all, Bret’s comments are extremely relevant in light of the realities of the condition in which one is likely to find vintage speakers today. Take that into account above all else.

My comments relate to the A-B ‘wars’ my friends and I had in high school. I had 2ax’s, a good friend had Large Advents, another friend had 5’s. (His 5’s always seemed to be on the DL with a blown mid or dead tweeter or something, and they missed most of this action. Too bad.)

The Advent went a bit deeper, no doubt about it, but most of the jazz and pop we listened to only went down to the 45-50Hz region anyway, so the difference wasn’t so great in practical day-to-day terms. We weren’t pipe organ fans, so low ‘C’ at 32 Hz wasn’t a concern.

The Advent was indeed more forward and ‘brighter’ than the 2ax, especially at retail. Most stores didn’t give the 2ax a fair showing (level controls turned down, disadvantageous placement on the ‘speaker wall’, etc.), mainly because they couldn’t make much profit selling AR. (AR was widely available at huge mail-order discounts, whereas Advent was marketed at full price—and therefore with full dealer profit—through limited-distribution retail stores only.)

The most common reaction to my 2ax’s was, “Boy, they didn’t sound like THAT in the store!” a reference to how good they really sounded in a normal home environment. Depending on the program material, either speaker could be made to sound marginally better than the other. Their essential traits always came through, with the 2’s slightly laid-back midrange and very extended, silky extreme highs being a marked counterpoint to the Advent’s more ‘exciting’ pop vocals and its occasionally slightly ‘brittle’ character.

Both very good speakers. To my ears, the warmth and ‘errors of omission’ of the 2ax were easier to live with than the less-forgiving slight aggressiveness of the Advent’s midrange.

BTW, Kloss’ protégé Andy Petite (later changed back to his native Greek Kotsatos) voiced the Large Advent, not Kloss. Kotsatos later went on to found Boston Acoustics, and their excellent speakers carried on the original Advent’s tradition of basic neutrality with just a touch of midrange forwardness thrown in.

Steve F.

#6 Steve F

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Posted 03 September 2009 - 12:46 PM

l

Now, this is theory, but it does not apply all that perfectly to the AR-2ax. The woofer/mid crossover point with the system is at about 1200 Hz, whereas the woofer/tweeter crossover with the Advent is only a bit higher up in frequency.


Howard Ferstler



The post-1970 2ax crossed over from woofer to mid at 1400Hz. (The 4x crossed over at 1200 Hz, not the 2ax.)

The Large Advent crossed over at 1000 Hz, actually a bit lower than the 2ax, so the 2-way vs. 3-way dispersion argument does not apply whatsoever to these two speakers, at least in the midrange region.

The relevant issue to be evaluated with these two speakers is the intentional voicing differences between the two. The 2ax was intentionally a bit laid back--as that was AR's mantra in those days--and the Advent had a slight bit of intentional midrange 'pop'--not too much, but enough to sound 'alive' if you liked it, 'aggressive' if you didn't like it.

Power handling? Not a whit's worth of difference in the real world for how those two mid-priced speakers were designed to be used in the 1970's. Both would get as loud as you wanted with receivers/integrated amps of 30-100 watts per channel in normal living rooms with normal program material--conditions that described about 99.9% of their usage, I'd bet.

Pick the ones in the best condition and enjoy them while looking for your 3as.

Steve F.

#7 Steve F

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Posted 03 September 2009 - 07:13 PM

I had no idea the Advent crossed over that low.

Howard Ferstler



From the original Advent brochure:

The Low-Frequency System
The operating range of the low-frequency driver
extends from the lowest frequency of musical importance
to the upper crossover point of 1,000 Hz.

The 2ax's 1400 Hz woofer-to-mid crossover is from AR's brochure, although, as we know, specific crossover frequencies are highly subjective and subject to both Eng interpretation and Mkt manipulation.

Steve F.

#8 tysontom

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Posted 04 September 2009 - 03:26 AM

The post-1970 2ax crossed over from woofer to mid at 1400Hz. (The 4x crossed over at 1200 Hz, not the 2ax.)

The Large Advent crossed over at 1000 Hz, actually a bit lower than the 2ax, so the 2-way vs. 3-way dispersion argument does not apply whatsoever to these two speakers, at least in the midrange region.

The relevant issue to be evaluated with these two speakers is the intentional voicing differences between the two. The 2ax was intentionally a bit laid back--as that was AR's mantra in those days--and the Advent had a slight bit of intentional midrange 'pop'--not too much, but enough to sound 'alive' if you liked it, 'aggressive' if you didn't like it.

Power handling? Not a whit's worth of difference in the real world for how those two mid-priced speakers were designed to be used in the 1970's. Both would get as loud as you wanted with receivers/integrated amps of 30-100 watts per channel in normal living rooms with normal program material--conditions that described about 99.9% of their usage, I'd bet.

Pick the ones in the best condition and enjoy them while looking for your 3as.

Steve F.


I think Steve F is correct about the 1000 Hz crossover of the Advent, but the slopes are so gradual that there is considerable overlap anyway between the woofer and the tweeter, so a few Hertz is unimportant here anyway.

As for the woofer, the Advent has the same resonance (41-43 Hz; Q of .728-.788) as and is very close in performance to the AR-3/AR-3a woofer, and therefore it has the advantage of more extension and significantly more power-handling than the AR-2ax woofer (resonance 56.7 Hz; Q of 1.37). The Advent even came very close to the AR-3/3a woofer on harmonic distortion: Julian Hirsch tested the original Advent with only 9% distortion at 25 Hz with 10 watts input; the AR-3 came in at 8% at 20 Hz with 20 watts input, so both woofers did very well down very low. For a number of reasons, therefore, the Advent woofer could probably handle 50% more power in the deep-bass frequencies than the AR-2a/AR-5.

When the AR-2ax and the Advent were compared side-by-side, the Advent usually came away sounding considerably more authoritative and “punchy” in the deep bass, even on jazz-ensemble bass drum; clearly, this powerful (AR-3a-like) deep bass was a big selling point for a low-cost speaker that became so successful over the years. I would therefore disagree with Steve in this assessment regarding that difference between the Advent and the AR-2ax.

The problem with the Advent was the unevenness in output in the 2-inch phenolic tweeter: in 1975, a major (competitive, but unnamed) speaker manufacturer tested the original and the newer version of the Advent, and the chief engineer stated this about the original version: “The tweeter comes in at around 800 Hz, at which level it runs with the bass unit over about 2 octaves. The tweeter itself is reasonable up to 7000 Hz, but above this goes into severe breakup. The overall energy response drops 3.5 dB from 200 Hz to 630 Hz. It then jumps up 2 dB at 800 Hz at which level it remains until 2000 Hz. At 3150 Hz it rises 3 dB, then falls steadily 3.5 dB out to 12500 Hz; at 20kHz, the response is down 10 dB.” Tweeter smoothness is clearly lacking, but probably not as horrendous as it sounds in that report (the AR-2ax tweeter, of course, was much smoother and more extended). Ironically, Julian Hirsch alluded to some response irregularities in his 1970 test report on the original Advent, but he also noted that the Advent tweeter had *excellent* transient response which would preclude any obvious ringing problems with the tweeter. Other "forces" are therefore clearly at work on the tweeter. The speaker was “voiced” (as mentioned by Steve F) probably more than measured, and this could account for some of the irregularities. This all relates to the Advent being a “bright, forward-sounding” speaker with powerful bass, but there might be some question as its ability to faithfully reproduce music in the upper-most frequency regions. This also relates to the reaction of how Steve F’s AR-2axs sounded at home, “Boy, they didn’t sound like THAT in the store,” meaning that the first impression in the store would always be won by a speaker such as the Advent; long-term listening satisfaction and realism might be more favorable to the AR-2ax.

--Tom Tyson

#9 Zilch

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Posted 09 September 2009 - 07:32 PM

As for the woofer, the Advent has the same resonance (41-43 Hz; Q of .728-.788) as and is very close in performance to the AR-3/AR-3a woofer, and therefore it has the advantage of more extension and significantly more power-handling than the AR-2ax woofer (resonance 56.7 Hz; Q of 1.37). The Advent even came very close to the AR-3/3a woofer on harmonic distortion: Julian Hirsch tested the original Advent with only 9% distortion at 25 Hz with 10 watts input; the AR-3 came in at 8% at 20 Hz with 20 watts input, so both woofers did very well down very low. For a number of reasons, therefore, the Advent woofer could probably handle 50% more power in the deep-bass frequencies than the AR-2a/AR-5.

I recently measured the low-frequency performance of a selection of acoustic suspension loudspeakers:

http://www.classicsp...?showtopic=5645

Indeed, the Large Advent and AR3a virtually superimpose, and the Smaller Advent runs a close second with respect to extension.

[The issues with the highs are moot; we know how to fix them.... :( ]

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#10 tysontom

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Posted 09 September 2009 - 10:17 PM

I recently measured the low-frequency performance of a selection of acoustic suspension loudspeakers:

http://www.classicsp...?showtopic=5645

Indeed, the Large Advent and AR3a virtually superimpose, and the Smaller Advent runs a close second with respect to extension.

[The issues with the highs are moot; we know how to fix them.... :( ]


Zilch,

Nice curves; however, did you ever discover why your measurements show such a bass rise down to resonance? Your measurements, though impressive, look almost like a 1-meter floor-corner-intersection measurement. Perhaps there is a calibration issue. I think your measurements should have shown a relatively flat output down to around 50 Hz; technically, the AR 12-inch woofer measures ±1.5 dB from 38-1000 Hz when measured (first with an WE640AA condenser mic; later with the B&K 4133) at 1 meter into half space, flush with the ground. D.B. Keele’s close-mic method (Keele also used the same-type B&K 4133 condenser microphone used by AR) closely replicates the old SE-103 and IRE30RPI test methods, so the old and new method should have been very close. AR’s 38-1000 Hz measurement reflects the AR 12W’s Q of 1.0 (.7 to 1.0 in the Advent), and amplifier damping factor of 1 (!), and still there was no more than a 1.5 dB rise in output at resonance.

Your measurements show a steady rise from below the point of radiation resistance down to resonance of more than 5 dB. There are undoubtedly variations over time with these woofers, of course, but there should not be such a rising output as shown in your graph.

Yes, even the Small Advent had the same (43-45 Hz) low resonance of the Larger Advent and the AR-3, and the bass curves would probably superimpose fairly closely, but Henry Kloss paid dearly for it with poor power-handling capability and much-higher harmonic distortion in the deep bass. The Small Advent had impressive bass until you turned up the wick. It had probably 3-times higher distortion below 30 Hz than the Large Advent which, in turn, had somewhat higher distortion than the AR 12-inch woofer. In the end, the less-expensive Small Advent sold fewer units, by far, than the more expensive Large Advent.


--Tom Tyson

#11 Zilch

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Posted 09 September 2009 - 11:25 PM

Yes, Ken and I are going to work out the reason for the difference, as discussed in that thread. Notwithstanding any of that, though, the relative performance of the various speakers is clearly illustrated.

I have AR2ax cabs on hand, but no woofers to measure at this point, alas....

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#12 ssmith3046

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Posted 27 December 2009 - 02:18 PM

I own both speakers and think they each have their own strengths. All in all I prefer the neutral sound of the AR-2ax's. To my ears they reproduce music with a realism and a honesty that I really enjoy. My other "go to" speakers are KLH Model-5's. They don't reproduce the bass like the AR's but I really enjoy them. I think the Advent's are really good speakers and at the time they were manufactured gave people a lower priced alternative.

#13 speaker dave

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Posted 28 December 2009 - 12:45 PM

BTW, Kloss’ protégé Andy Petite (later changed back to his native Greek Kotsatos) voiced the Large Advent, not Kloss. Kotsatos later went on to found Boston Acoustics, and their excellent speakers carried on the original Advent’s tradition of basic neutrality with just a touch of midrange forwardness thrown in.

Steve F.


Hey Steve,

I thought I'd heard that Andy did the Small Advent when Henry got busy with projection TV (Implying that Henry did the Large Advent)?

Did Henry design any of the Advents?

David

#14 speaker dave

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Posted 28 December 2009 - 01:28 PM

Zilch,

Nice curves; however, did you ever discover why your measurements show such a bass rise down to resonance? Your measurements, though impressive, look almost like a 1-meter floor-corner-intersection measurement.

Your measurements show a steady rise from below the point of radiation resistance down to resonance of more than 5 dB. There are undoubtedly variations over time with these woofers, of course, but there should not be such a rising output as shown in your graph.


--Tom Tyson


We discussed this some in another thread here:

http://www.classicsp...amp;#entry81422

It does seem like a lot of rolloff above resonance but I think it comes from a few different issues. As you know, nearfield curves are a measure of power response. I think the droop towards the midrange is a combination of crossover rolloff and woofer inductance. Both of those would be designed in to make the farfield response flatter as they compensate for natural directivity rise and also 4pi to 2pi transition of a small baffle area.

Note that the AR published curves would usually be of the system buried flush in the ground and would be flatter because woofer directivity would still be a factor.

Most bookshelf speakers seem to be designed with a fair amount of woofer LF rise to flatten their free space response. Stereophile magazine has published many curves, always with spliced nearfield woofer measurements, and a healthy LF bump seems to be fairly typical.

The 25dB vertical scale also tends to exagerate the effect.

Note that this is an effect of crossover or self inductance rather than evidence of high woofer Q, so there is no discrepancy with impedance curve defined Q.

David

#15 Carlspeak

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Posted 28 December 2009 - 01:48 PM

I believe evidence of a high Q would be revealed in a WT3 test. Mine done on a number of AR4x's range from 0.9 to 1.25, which I attributed to design intent to give these little guys some bass boost.
IT'S ALL ABOUT THE MUSIC!

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#16 anachrophile

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Posted 03 January 2010 - 06:13 AM

Hi, all. I am new to the CSP but enjoyed this topic. I had written something at length, but lost it by hitting the wrong button so this will be brief.

I have owned both LA and AR2a (not 2ax). At one time, I could switch between them very easily using a Niles box in my own room. I came away liking the Advents better (and still have 2 of them, plus 8 smaller advents in a special project--Google QuAdvent). Two others who heard this demo liked the AR2as better, citing more smoothness. I gave the AR2as away to one of those guys. The AR2as are the ones to own if you want something made with pride (notwitstanding those silly potentiometers for contour control).

A Woofer Tester run on one of my original LAs shows f = 42.5 Hz and q = 0.88. There is a broad peak at 630 Hz for the Xover (electrically, at least, it may be even lower than Advent claimed). This Xover was rebuilt with new components, but the same values. BTW, the AR used much better Xover components (hermetically sealed oil/paper I think, and they were SPOT ON when I measured them even after probably 45 years!).

Both speakers reflect rational choices about design, and it's remarkable how well they still sound. I liken the experience of listening to them to taking a ride in a really neat old car: gets you there, is lots of fun, and you can sense the genius. One wonders what those old masters could have done with modern software to place drivers and modern manufacturing to shape baffles, etc.

#17 soundminded

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Posted 03 January 2010 - 02:09 PM

I've recently completed restoring a pair of rescued AR2axs. Refoamed woofers, recapped crossover (low cost Dayton NPCs like always for me), replaced defective midrange driver, and cleaned pots. With all controls on the amplifier and speaker controls set to their indicated flat positions the speaker exhibits the dull mediocre sound I recall from the 1960s and 1970s I remembered so well. But with the midrange pot turned down to slighly less than halfway, the tweeter up full, considerable but careful bass and treble boost from an equalizer and tone controls, and a slight cut at 500 hz, the speaker has proved to be an outstanding reproducer, remarkably accurate. Noteworthy is the incredible dispersion and smooth response of the tweeter. Currently power is from a Sherwood low cost 100 wpc receiver and the source is a Toshiba DVD. The tweeters appear to be functioning properly. Both tweeters perform identically and there is no crackling or other signs of deterioration. These appear to be a late production units. Bass is good. I'd have to say that at the moment, optimized this way, this speaker now clearly outperforms the unoptimized KLH Model 6 I used as a benchmark for so many years.

I've also repaired the woofer I damaged on the AR2as. I've got another set of AR2ax midranges and I haven't decided what to do with them. I'm toying with using the AR2ax midrange drivers and replacing the Orange AR3 dome tweeter whose output seems to be next to nil. Bass on the AR2a using the cast frame alnico drivers was nothing short of remarkable and the driver's outer suspension seems to resemble the current line of Peerless 10" XLS and XXLS drivers. However, be warned, I damaged that one driver in an accident with a Pioneeer SX950 receiver so even that receiver can put out enough power to overdrive the woofer. I'd consider fusing them maybe with a 2 amp slow blow fuse.

I'm no longer sure the dome midrange of the AR5 is an advantage over the cone driver of the AR2ax. The AR2ax midrange can probably go much lower with less risk of damage and its dispersion at those frequencies being less than the AR5 dome is a closer match to the tweeter. This is consistent with my goal of creating reflections that are as flat as possible.

I'll begin re-engineering both of them in the not too distant future, principly with multidirectional (mostly reflecting) arrays of additional small poly dome tweeters.

#18 JKent

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Posted 03 January 2010 - 03:56 PM

That QuAdvent site is pretty interesting. Here's the link:
http://macro.lsu.edu...nt/QuAdvent.htm

Soundminded--I wonder how Roy's HiVi tweeter replacement will effect the sound of the 2ax. After I finish my OLAs and have a chance to compare them to the 2ax (with and without Pete's BSC gizmo) I may replace those old AR tweets. We'll see....
Kent

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#19 soundminded

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Posted 03 January 2010 - 05:11 PM

That QuAdvent site is pretty interesting. Here's the link:
http://macro.lsu.edu...nt/QuAdvent.htm

Soundminded--I wonder how Roy's HiVi tweeter replacement will effect the sound of the 2ax. After I finish my OLAs and have a chance to compare them to the 2ax (with and without Pete's BSC gizmo) I may replace those old AR tweets. We'll see....
Kent



It will not have the high frequency dispersion of the AR tweeter but it will be louder. It will cut off at an angle at lower frequencies like other current tweeters.

I've considered experimenting with Dayton neodymium tweeters. The dispersion of the AR tweeter seems to me to be the result of its dome's small diameter, its highly projected forward geometry, and the fact that it projects out from the front of the baffle without any recess or notch around it. By cutting away the plastic shroud around the front of the neodymium tweeters with a cuttoff bit in a Dremel tool, if I'm careful I should be able to expose the dome without damaging it. The housings are small enough to allow them to be very closely spaced and they are more efficient than the AR tweeters. An angled array might work well.

http://www.parts-exp...tnumber=275-030

There are some new tweeters on Parts Express' web site that have their domes completely exposed but the geometry is a much shallower secton of a sphere than the AR dome.

http://www.parts-exp...tnumber=279-118

Looking at them carefully, they look very similar to me.

#20 genek

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Posted 03 January 2010 - 06:43 PM

With all controls on the amplifier and speaker controls set to their indicated flat positions the speaker exhibits the dull mediocre sound I recall from the 1960s and 1970s I remembered so well. But with the midrange pot turned down to slighly less than halfway, the tweeter up full, considerable but careful bass and treble boost from an equalizer and tone controls, and a slight cut at 500 hz, the speaker has proved to be an outstanding reproducer, remarkably accurate.

My 1975 2ax's have been set with the tweeter control about 10 degrees down from full and the mids about 20 degrees down from full for most of the time since I bought them new. I rented an apartment with heavy drapes and shag carpeting for a couple of years in the early 80's where I turned everything up to full and added some treble boost, but in every home I've had where the decor was under my control, full up has been too bright for me.




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