AR11 VS AR3a

[DON]

I've never owned a pair of 3a and probably never will unless I come across one of the "estate sale" wonders but I do have a pretty nice pair of AR11s that seem to be in good operational condition. I have some work to do on the cabinets but they should turn out really nice. They were refoamed by the previous owner but he used some adhesive other than what is usually used and it looks very sloppy. It's some type of thick rubbery substance but they are air tight. I'd like to refoam them correctly but I'm not sure I can get this adhesive off without damaging the woofer cones. They sounded very good for the short time I played them.

I'd like to know how the 11s sound compares with the 3a.

Another question totally unrelated to the title. My multimeters won't stabilize when I test for resistance or capacitance but act as if they're searching and can't find the right reading. Should the digital readout stop on one reading after a few seconds? Both meters act the same. Thanks Don.

[Steve F]

From a post of mine in '07:

The AR-11 was introduced in March of 1975 as part of the first wave of the Advanced Development Division (ADD) product family, along with the 10 Pi and the MST/1.

The 11 was essentially a refinement of the basic 3a design—a bookshelf-sized 3-way speaker, utilizing the 3a’s 12-inch woofer and 1 ½” dome midrange. However, the 11 (along with the 10 Pi) employed AR’s first incarnation of the ferro fluid-cooled ¾” dome tweeter. The use of ferro fluid in the tweeter’s voice-coil gap greatly increased the power handling of the tweeter, allowing the crossover to be redesigned with a greater voltage drive to the HF section. This resulted in much greater HF output from the 11 and 10 PI compared to the 3a, and completely resolved the “not enough highs” complaint that was common to the older speakers. Importantly, the 11 retained the smooth, uncolored, low-distortion character of the 3a.

The 11’s cosmetics were significantly upgraded as well, although the degree of “improvement” is certainly open to question and remains a matter of personal taste.

The ADD products were marketed as a limited-distribution line of goods, where AR was attempting to correct their years of dealer neglect and re-establish a measure of dealer profitability (and hence, dealer loyalty). This strategy was not entirely successful however, as the combination of a decade of ‘dealer-be-dam*ed’ sales/marketing policies coupled with the rapidly-changing 1970’s consumer electronics marketplace meant that AR was not able to reclaim their previous leadership status with the ADD line.

Considered solely as a product, however, the AR-11 was a terrific speaker. Many experienced AR aficionados—myself included—feel that the 11 combined the 3a’s best acoustic qualities (great deep bass and smooth, natural, widely-dispersed midrange) in a good-looking, more modern speaker with truly excellent, no-excuses high-frequency response.

Highly recommended.

Steve F.

[HarryM]

Don,

The first things you should do is recap the 11's and get the woofers cleaned up with the correct surrounds. It will make quite a bit of improvement from what they are now. What I would do with the surrounds is try peeling it off very gently. You could be lucky and it's not sticking very well to the cone. If it doesn't want to come off nicely for you, you can send them out and have them redone. You can't use any kind of chemicals on the cone so peeling and scraping is the only way. Hopefully some others will chime in with good tips.

The difference in sound between the 3a's and the 11's to me is the 11's highs are more noticeable, less mid range and a little less very low bass.The 3a's are mellower sounding then the 11's and are very well suited for orchestral type music on vinyl. If you find when you are listen to your 11's that you are turning down the treble and turning up the mid range and bass the 3a's would be great speakers for you. I personally don't find the highs lacking with the 3a's, I think it's more the sound level of the tweeters is lower if that makes sense.

I have the same problem with my digital meter. The one with the sweep gauge doesn't do that.

Harry

[Carlspeak]

Here's a system impedance and phase of an AR11. Note the cabinet resonance is on par with AR3a at about 42 hz. Q is a bit low at 0.6. This AR11 was fitted with a new tweeter from vintage-AR which is a modded ABtech tweeter. I'll be writing more about the tweeter soon in a new thread.

Most of the impedance above 100 hz runs in an amp-comfortable 4-8 ohm range with a dip to 2 ohm at around 9 kHz. I don't recall how the level switch was set for this test.

[DON]

Thank you for your replies. I've had a chance to compare the 11s to another speaker that I liked very much and I've noticed some real differences. On one song what I thought was "electronic" noise purposely recorded that way was really very musical with individual instruments very clear on the ARs. The overall bass is more prominent but tight and not at all boomy. The highs and upper midrange are well dispersed and provide a wide stereo image. The ARs are not quite as open as the other speakers and the soundstage is not as deep front to back........but not lacking. I need to listen to many more recordings.

I'm already waist deep in speaker restoration and I run out of energy in the early afternoon so I won't be tackling another recap or refoam anytime soon. They sound good as they are. I don't see any sign of sealant behind the woofers so I may take one out to see what he used if anything. Are the 12" woofers 2xxxxx03-1 interchangeable with the -2s? One has a round magnet and one has a square magnet.

No suggestions on my multimeter?

[JKent]

I'd like to refoam them correctly but I'm not sure I can get this adhesive off without damaging the woofer cones.

Don.

I don't know how bad the woofer refoam is, but here are my AR91s: http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=6565#entry88793

See post #12. The previous owner did what I considered a sloppy glue job and I did not know how to undo it so I sent the woofers to Bill LeGall (Millersound in PA). He fixed 'em up good as new and I thought the cost was reasonable. He's a good guy and a master of his trade.

If you're like me you have no hesitation to do a routine re-foam. But when I have a mess on my hands I send the speakers to Bill. He recently reconed my Cizek woofers and they're better than new!

Kent

[DON]

Thanks Kent I'll keep Bill in mind if I run into trouble when I try to do them.

I'd post photos but resizing them is giving me fits.

[Madar80]

Hi everyone, I've both the AR-3a and the AR-11 speakers, and there is indeed a difference in the bass. The AR-3a bass is deeper, smoother and go lower, whereas the AR-11 bass is lighter and more subtle I would say, as you can hear a more discernable difference between bass notes. Listening to the AR-11, I discovered some new aspects of the bass notes of my favorite records, that there a difference between "high bass notes" and "low bass notes". It's like if the bass is singing. 

Sometimes I change my speakers from AR-3a to AR-11 (and vice versa), depending if I prefer to hear a deep and smooth bass or a "singing" bass.

[DAA]

I truly love my AR11Bs. They are to me a modern AR3a.  I feel they are the finest refinement of the AR three way (10pi too). They need the mid and high caps replaced. The bass cap it typically fine. Make sure the proper foam is used on the woofer.  I had a pair of AR3a that I liked very much, but felt they were too mellow up top. Loved the bass and mids. For me the 11/11B fleshed out the top end and kept all I loved about the 3a.  Bass is a little different—3a seems deeper but looser. 11/11B is still deep and tighter  Solo acoustic bass is stupid good on my 11Bs.  Both great—I prefer the 11/10 series overall.  

[lARrybody]

DAA. Have you ever listened to the AR 91 or the AR58S ?  They are basically the same speaker, different cabinets. To me that is the ultimate version of the AR3a  3 way.   The AR 11 is very good   But the redesigned dome tweeter and midrange really shine on the AR 58S and 91.   

 

[DAA]

Yep. I had AR91s—-excellent speakers.  I prefer my 11Bs.  Maybe it’s just me, but I find them extraordinary!   

[lARrybody]

They are brighter. A little too much for me I think. I am currently running my 58S’s at -6 db on the tweeter and flat on the midrange.  My 91’s have been out of rotation to long. Currently working on my third pair of 3a’s.  I do like their sound. 

[giovanni56]

On 7/3/2013 at 17:42, Steve F said:

Da un mio post nel '07:

L'AR-11 è stato introdotto nel marzo del 1975 come parte della prima ondata della famiglia di prodotti Advanced Development Division (ADD), insieme al 10 Pi e all'MST / 1.

L'11 era essenzialmente un perfezionamento del design di base 3a: un altoparlante a 3 vie delle dimensioni di una libreria, che utilizza il woofer da 12 pollici del 3a e il midrange a cupola da 1 ½ ”. Tuttavia, l'11 (insieme al 10 Pi) ha impiegato la prima incarnazione di AR del tweeter a cupola da ¾ ”raffreddato a fluido ferroso. L'uso del ferro fluido nel gap della bobina mobile del tweeter ha notevolmente aumentato la gestione della potenza del tweeter, consentendo di riprogettare il crossover con una maggiore tensione di trasmissione alla sezione HF. Ciò ha prodotto un'uscita HF molto maggiore dall'11 e dal 10 PI rispetto al 3a e ha risolto completamente il problema di "non abbastanza alti" che era comune agli altoparlanti più vecchi. È importante sottolineare che l'11 ha mantenuto il carattere liscio, non colorato e a bassa distorsione del 3a.

Anche i cosmetici dell'11 sono stati notevolmente migliorati, anche se il grado di "miglioramento" è certamente discutibile e rimane una questione di gusto personale.

I prodotti ADD sono stati commercializzati come una linea di prodotti a distribuzione limitata, dove AR stava tentando di correggere i propri anni di abbandono del rivenditore e ristabilire una misura della redditività del rivenditore (e quindi della lealtà del rivenditore). Questa strategia non ha avuto del tutto successo, tuttavia, poiché la combinazione di un decennio di politiche di vendita / marketing `` dealer-be-dam * ed '' insieme al mercato dell'elettronica di consumo degli anni '70 in rapida evoluzione ha fatto sì che AR non fosse in grado di rivendicare il loro precedente status di leadership con la linea ADD.

Considerato esclusivamente come un prodotto, tuttavia, l'AR-11 era un altoparlante eccezionale. Molti esperti appassionati di AR, me compreso, ritengono che l'11 abbia combinato le migliori qualità acustiche della 3a (bassi profondi e medi fluidi, naturali e ampiamente dispersi) in un altoparlante di bell'aspetto e più moderno con alti davvero eccellenti e senza scuse risposta in frequenza.

Altamente raccomandato.

Steve F.

It seems to me that the first cream white dome tweeters, installed on the Ar10 and Ar11, did not have ferrofluid, but only the following ones with the dark gray dome, is that correct?

[AR55]

Yes

[RoyC]

1 hour ago, giovanni56 said:

It seems to me that the first cream white dome tweeters, installed on the Ar10 and Ar11, did not have ferrofluid, but only the following ones with the dark gray dome, is that correct?

Some AR-11/10pi owners prefer the earlier tweeters, which typically have more uniform output. The black dome version tends to have less uniform output due to the variable nature of old ferrofluid.

Roy

[giovanni56]

Il 13/2/2021 alle 20:53, RoyC ha detto:

Alcuni possessori di AR-11 / 10pi preferiscono i tweeter precedenti, che in genere hanno un output più uniforme. La versione con cupola nera tende ad avere un rendimento meno uniforme a causa della natura variabile del vecchio ferrofluido.

Roy

Se il ferrofluido è in condizioni normali, il tweeter che ne è dotato dovrebbe avere una risposta in frequenza più lineare e un'impedenza di picco più smorzata a Fs per una migliore compatibilità con il filtro e una maggiore tenuta in potenza. Se non sbaglio, i tweeter a cupola nocciola chiaro, che non hanno ferrofluido, nelle primissime versioni di Ar 10 Pi One (quelli con interruttori a scorrimento), avevano il filtro passa alto con condensatore da 8uF e induttanza 0, 1 mH, mentre tutte le versioni successive avevano il condensatore da 10 uF; Roy, could you kindly give me confirmation about the tweeter and the 8 uF capacitor, thank you.

[Illf8ed]

I joined this site a couple of days ago after finding a string about AR LSI-2.  I bought  a set of LSI-2 and also AR-10pi a week ago.  With the 10pi, one has the original cream colored tweeter dome, the other has a replacement newer tweeter with dark grey dome.  Is this going to be unbalanced based on above?  These speakers are laying on their backs waiting for new woofer surrounds to arrive.

[AR55]

Unfortunately, the 1^st generation AR-11A’s that I picked up a few years ago had blown tweeters, so I wasn’t able to compare them sonically to my 2^nd generation AR-11B’s tweeters.  That said, I don’t believe that the difference between the two will be all that noticeable.  Other than adding ferrofluid, I think that the only other noticeable change was the color of the fabric for the dome.  The metal work and voice coil/surround assembly (part no. 205057-1) introduced in the first generation 10π/11 tweeter was carried over to the second generation tweeter.  For that matter, with the exception of the ¾” tweeter found in the dual dome assembly for the 9Ls(i), 98Ls(i) & 78Ls, it looks like the 205057-1 voice coil/surround assembly was used by AR in all their speakers with ¾” dome tweeters starting with the ADD series (10π/11), continuing through the AR-9 series & ending with the Post-Classic series.

[Illf8ed]

AR55, thank you for that.  I just tried these 10pi after putting new surrounds on the woofers.  That played for a bit then one speakeR went out and the other played only on the mid dome.  Switching the three position impedance controls brought some back.  The guy that sold these told me those switches were dirty.  If the changing the switch position brings it back it’s not the capacitor, right?

[Illf8ed]

I’m going to try these 10pi comparing to my ESS.  They’re going to have to be very good be favorable to the ESS amt1b.

[RoyC]

On 2/16/2021 at 7:24 PM, giovanni56 said:

Se il ferrofluido è in condizioni normali, il tweeter che ne è dotato dovrebbe avere una risposta in frequenza più lineare e un'impedenza di picco più smorzata a Fs per una migliore compatibilità con il filtro e una maggiore tenuta in potenza. Se non sbaglio, i tweeter a cupola nocciola chiaro, che non hanno ferrofluido, nelle primissime versioni di Ar 10 Pi One (quelli con interruttori a scorrimento), avevano il filtro passa alto con condensatore da 8uF e induttanza 0, 1 mH, mentre tutte le versioni successive avevano il condensatore da 10 uF; Roy, could you kindly give me confirmation about the tweeter and the 8 uF capacitor, thank you.

With the exception of the last sentence, your post is in Italian. I'm not sure what you are asking regarding an 8 uf capacitor.

[rjr513]

24 minutes ago, RoyC said:

With the exception of the last sentence, your post is in Italian. I'm not sure what you are asking regarding an 8 uf capacitor.

Roy...This what I think he's asking...clarification on the two different tweeters using different tweeter capacitance

If the ferrofluid is in normal conditions, the tweeter that is equipped with it should have a more linear frequency response and a more damped peak impedance at Fs for better compatibility with the filter and greater power handling. If I'm not mistaken, the light hazel dome tweeters, which do not have ferrofluid, in the very first versions of Ar 10 Pi One (those with slide switches), had the high pass filter with 8uF capacitor and inductance 0, 1 mH, while all later versions had the 10 uF capacitor

[RoyC]

Hi Ron...I'm afraid I can't provide any insight at all. Either I have forgotten, or was not aware, there is a version of the 10pi without a 10uf capacitor on the tweeter(?). My last encounter with a 10pi was a few years ago when I removed the drivers from a beat up pair of cabinets for Larry/"Vintage_AR". The tweeters had black domes and the capacitor was 10uf.

Roy

[giovanni56]

9 hours ago, RoyC said:

Ad eccezione dell'ultima frase, il tuo post è in italiano. Non sono sicuro di quello che stai chiedendo riguardo a un condensatore da 8 uf.

If I am not mistaken, the light hazel dome tweeters, which do not have ferrofluid, in the very early versions of Ar 10 Pi One (the ones with slide switches), had the high pass filter with 8uF capacitor and 0, 1 mH inductance, while all later versions had the 10 uF capacitor; Roy, could you kindly give me a confirmation about the tweeter and the 8 uF capacitor, thanks

[RoyC]

5 hours ago, giovanni56 said:

If I am not mistaken, the light hazel dome tweeters, which do not have ferrofluid, in the very early versions of Ar 10 Pi One (the ones with slide switches), had the high pass filter with 8uF capacitor and 0, 1 mH inductance, while all later versions had the 10 uF capacitor; Roy, could you kindly give me a confirmation about the tweeter and the 8 uF capacitor, thanks

I cannot provide confirmation. What is the source of your information?