Anyone see these?

[ReliaBill Engineer]

Unfortunately, there is more to refurbishing a tweeter, and getting it to sound good, than just removing the original dome+VC, and replacing it with a China-made unit. 
 

You need to closely examine how the original unit was made. And how it was assembled. IMO most people greatly cheapen the performance by cutting corners. I’ve seen countless YT vids of people doing this on AR and Advent speakers. 
 

One major corner that is cut is removing the batting from behind/under the dome. Over and over, I’ve seen people remove the dome+VC, then clean up the VC gap….AND remove the batting/damper  that was under the original dome. And then it’s never replaced. That’s a disaster in the making, and at a minimum it results in (mostly) wasted effort. 
 

The dome has a mechanical impedance. It also produces as much sonic energy under the dome as it does on the outside of the dome going into the room. (Woofer does too!) By not matching the mechanical impedance using batting/damping under the dome, the mechanical impedance is mismatched between the dome’s outer and return movement. By not absorbing the sonic back wave, the dome will resonate at multiple frequencies, causing blurring of detail and peaky distortion at higher volumes.

Replacing original domes+VC with the Chinese units is a MOD, not a repair/refurb.

And most all people experienced in legacy AR speakers can readily spot a modified AR tweeter dome, as well as a change in the faceplate and wiring. 

 

[Andre_Db66]

So just use an unfitting chinese variant by the name of HiVi?

IMHO if it works and sounds allright, its fine.

Perhaps you have a point with regard to the batting under the dome and the thought definitely has crossed my mind. On the contrary to original AR tweeters the VC can easily be removed and tested wity the batting. When the time comes i shall do that. First i have to find suitable material to put there. Leaving the old was no option as it was crumbling apart.

[Andre_Db66]

Talking about the woofer and the mechanical impedance. I wonder how effective it is to have fibre glass in the cabinet if it is not placed exactly as it was from factory. Considering the the 500 to 600 hz range i am having resonance problems with, concerning piano notes, there must be a right and wrong way, rather that just stuffing the right weight of material in hoping it'll be allright?

I have no virgin cabinets for study purpose but i am convinced i did something wrong while putting it back.

[ReliaBill Engineer]

The 2ax and 4x I have are still original placement of the rock wool. All I did was remove enough from behind the woofer to access the XO board.

With the cab on its back, woofer hole up, the batting is placed against the vertical sides, bottom top and sides. Then additional batts are stacked vertically from the tweeter end to the woofer cut out. Then a batt is placed against the bottom, covering the XO board. Finally, the space behind the woofer is filled with both vertical and horizontal batting pieces, where a “cup” is formed to accommodate the woofer magnet. Then scrim (paper) is placed over the batting to contain dust out of the woofer.
 

Below, you can see the vertical batts, then a stack of vertical batts that fill the tweeter and mid area:

 

 

[Andre_Db66]

Thanks for those pics...

In the first i can see it is very similar to the way an advent is filled up however the difference being the foam instead of fibreglass and there is batting on the backside. There will be once the stuffing is completed.

The cabinets i have opened i refilled them with fibreglass as though you were eating cotton candy. All fluffy little bits randomly dispersed around the cabinet. I am starting to believe this is affeccting the resonances in the cabinets. This is also the reason i started the other thread. My 2 sets of 3a are filled with fluffed fibre and the LST with random pieces leaving cavities. Due to the appearance of compacting in your pictures it would seem more material than the weight recommended here on CSP. Maybe i should worry less about weighing the stuffing beforehand and get going with a similar approach as shown above.

I am a little hesitant as i am also very curious about the Advent method. Obviously having 2 sets of 3a i can make a nice A/B comparison.

Pressed for time some loudspeaker experiments are in the waiting list to be done asap.

Still nosedeep in a Sansui AU919 project...

[ReliaBill Engineer]

Over damping seems to have been key to achieving the early AR sound. I see it in the early tweeters, midranges, and in the cabinets for the woofers. Layers of 2” batting in the cabs is the most dense way of laying in the rock wool.

The tweeter domes were stuffed with fiberglass batting. Also the midrange domes. Also the cone tweeters and midrange drivers.

[Andre_Db66]

23 hours ago, ReliaBill Engineer said:

Over damping seems to have been key to achieving the early AR sound. I see it in the early tweeters, midranges, and in the cabinets for the woofers. Layers of 2” batting in the cabs is the most dense way of laying in the rock wool.

The tweeter domes were stuffed with fiberglass batting. Also the midrange domes. Also the cone tweeters and midrange drivers.

Even on the outside of the 2ax mid, or was that to soften and diffuse the output?

[genek]

Can you really call something that is highly damped overdamped if it was what produced the result you were looking for?

[Andre_Db66]

Pretty much my point with regard to the thread topic. My sansui au919 is almost accomplished and being tested with 2ax that i refurbished. Refoam and chinese VC. The combo sounds wonderfully balanced. Perhaps there is still room for improvement but it is possibly enough for a lot of people who would care to sit and listsn. Only audiophile perfectionists can hear that, while it is actually perfectly enjoyable.

I love to tinker and that is why i will seek out the progress which undoubtedly can be made. Tweeter dome chamber batting, cabinet stuffing. Although it might be pointless as the mid driver is not all that good...

[genek]

OTOH, if the result you're looking for isn't original sound, we could call it a mod or tweak...🤔

[Andre_Db66]

Hah... its never going to happen. I gave the 2Ax to a friend today. They match his interior and he is delighted by the sound. So they are in a good place now. Sansui almost finished. So focus will be on the cabinet stuffing of the 3a and lst to minimize disturbing resonances. I am going to look for some foam to mimic Advent NLA. See the difference between a restuffed set of 3a with fibre glass and a set with foam.

Will continue my findings in the corresponding thread.

Once i finished that quest i will tinker with the batting behind the chinese VC dome of a set of AR5. Also will i redo the cabinet stuffing depending on what i discover with above experiment.

Gene, isnt original sound a bit far fetched? I have not grown up admiring these speakers belonging to friend, family member or foe. I havent a clue what they should sound like. I do know however what i want to hear and what i think is right or wrong. Obviously that is to be considered subjective. I wonder how many forum members have the same as me. All speakers, amps etc can change in sound signature over so many years. So who is to say that when you get to know the AR speaker sound signature at such late stage, whether you are listening to the original sound signature.

We dont want dull sound but crisp and clear. If dull is how it became, in all fairness it should be improved. How? That is done taking into consideration also the budget and/or knowledge of originality. I know there are members here who know these speakers from the early days but it cannot be told how they should sound, it must first be heard.... there are no more wonderful shows comparing live to recorded as in the old days.

Cutting corners? Yes. Rambling? Forgive me...

[genek]

If you're doing it all by ear, then it's totally subjective. That's why we nag people for measurements when they claim to have repaired or restored speakers with new or rebuilt components.

[Andre_Db66]

I agree to it being subjective. However, do ordinary people have access to these tools? The parameters for doing this extensive measuring, who has these? I know for sure that nobody in my country would be able to get AR drivers/speakers up to par with originality taking into consideration all the above. I think when you bring them to a repair shop they will get them up to speed in a similar way.

I know this because i called a reknowned company here and found out their methods.

My AR3a improved along with AR3a both have profesionally replaced woofer edges made of rubber to give a good example....

I am just saying that how AR sounded when new has ultimately been watered down over almost half a century. Restoring them might more feasable in the US close to the source where knowledge is more abundant. Abroad i doubt many people can actually recollect this. Not so long ago AR was not very popular or well known at all here in Netherlands. Patially because they look tinkered with from factory to begin with. To be honest, that kept me away from them the best part of my life, until i discovered their "Boston" signature.

[genek]

Frequency response hardware and software are readily available as add-ons for computers and smartphones. These consumer products are not as accurate as today's professional equipment, but you would be comparing anything you measure with data obtained 40+ years ago on the equipment of that period. Original response curves for most AR models are not hard to find, either here on CSP or elsewhere on the net.

Of course, none of this is needed if your objective is just to produce something that "sounds good." It's only needed if you intend to present your results as something more authentic to original.
 

[Andre_Db66]

Well it seems common practice here to fix things to working order, rather than to obtain originality. Giving the 2 examples of the rubber woofer surrounds and chinese voice coils implemented by professionals. I am not alone in finding the result agreeable as the bar originality seems to either use completely original, regardless of the aging materials involved, or paying top dollar for import refurbished as offered by some in the US. Hardly noone here is following the latter path because as i have mentioned sometime ago, the speakers cost perhaps 450 on craigslist, making it ludicrous to pay 80$ ex tax and shipping to have original replacements. The rubber surrounds are nowhere to be found on the market for quite some years now, but have been used believing they would at least last a lifetime, regarfless of originality or any kind of frequency response measurement.

As far as i have read acoustic supension should not even be 100% sealed as the principle would not work that well. The cone has to slowly return to its passive position. The woofers with rubber surround tend to do this slower than my refoamed versions. That is a clear sign already that something is different, however, i do not find that audible.

Perhaps if i would have some ar3a that are fully spec, i could have a taste of originality. Otherwise it is like a chinese whisper.

I have had the HiVi in a set of LST2 and tried to sell them. Nobody paid attention. They sounded very good. When i offered them with old tired crappy original tweeters, they were sold. Personally i preferred the HiVi version, but they looked tampered with. In my personal opinion, i wasnt halpy with them because i preferred the tweeters to fit properly. The chinese vc is the next best thing to originality and came very close to the refeshing taste of new tweeters, unlike the tired old ones. But hey, originality sells, so i did not dare to upgrade the originals to chinese vc. I have done this with ar5 and 2ax and they look great and sound great.

I will see about the sound check apps and tools as my sansui is coming to a finishing stage. I am anxious by now to tinker with these ar5. Wonderful speakers btw. Rather under acknowledged imho. Can really hold their own against 3a.

Plz redirect me to some of the sites where i can find data for measurements. Tia

 

[genek]

Pretty sure that the more technically knowlegeable of our CSP members (Roy!) would tell you that an AR woofer retrofitted with a rubber surround is not performing comparably with its original surround. I've lost track of all the alternative surrounds people have asked about that failed to measure up. And while the HiVi was the preferred replacement tweeter back in the days when rebuilds and repros didn't exist, it required crossover mods to get closer to original on-axis performance and still didn't have the dispersion. Might be good enough elsewhere, but CSP is nitpicky originalist territory.

[RoyC]

9 hours ago, genek said:

Pretty sure that the more technically knowledgeable of our CSP members (Roy!) would tell you that an AR woofer retrofitted with a rubber surround is not performing comparably with its original surround.

Yes he would.

Modern rubber replacement surrounds tend to be rather heavy and are primarily used for subwoofer and automobile driver repair. Additionally, I'm not aware of a replacement that would even fit the AR 12 inch woofer. If there is one, there is a strong likelihood that it would add too much mass and/or significantly reduce compliance.

Regarding other aspects of the discussion above...This is a restoration forum, and there are still a number of us who are very familiar with the original sound of AR speakers. We owned them when new, and have been working (as enthusiasts and professionally) to maintain them for decades.

Andre...regarding your cabinet damping concerns. When we were putting together the AR-3a restoration guide, we conducted dozens of measurements of various types, amounts, and placement of fiberglass, polyester, and "Acousta-Stuf".  Response measurements consisted of Fs of the individual woofers and Fc after installation. Measurements were verified between us, and valuable insights were offered by Ken Kantor along the way. The upper bass/lower midrange area you are dissatisfied with is not likely to be influenced by the damping material. Foam rubber was not tested, but it should be noted that Advent restorers often replace the foam rubber blocks with the earlier fiberglass, and that later Advents were stuffed with polyester. It could be that Advent tried the foam rubber for awhile simply because it was easier to handle in the factory, or less expensive.

Roy

[Andre_Db66]

I have 2 sets of advent 1 and a set of NLA. All have the foam. Also do i have a set of Goodmans Magnum K with the discussed air cushion suspension tech, it also carries foam.

Roy, you are saying that in all speakers the foam could be replaced with fibre glass to what advantage may i ask when foam has not been tested as a replacement? The fibre glass is annoying to work with, so wouldnt it be preferable to place foam in the 3a and lst? Both options seem to work.

I sometimes think it would be better to replace the rubber surrounds with foam as i will not live to see the day they might rot again. Compliance wise i do agree it must be different.

The 3a improved surrounds have been done 20 years ago. So there is no more evidence of manufacturers. The 3a set i have with rubber surround, i would not know who did that or when. I do know the first carries a part number, the latter is blank.

[RoyC]

11 hours ago, Andre_Db66 said:

Roy, you are saying that in all speakers the foam could be replaced with fibre glass to what advantage may i ask when foam has not been tested as a replacement? The fibre glass is annoying to work with, so wouldnt it be preferable to place foam in the 3a and lst? Both options seem to work.

Density, type, and amount of damping material is important to the original design. Along with Fs and Fc, Q is another important parameter to consider, so just replacing damping material with something else is not as straightforward as it may seem. (I forgot to mention above that Q was something else we measured). Modern fiberglass is really not that difficult to use, and its properties are well known for the restoration of AR speakers. Advents were manufactured with more than one type of material, but the amount of each type is critical to its original design.

You simply may not find AR speakers to your liking. You can always head over to the Mods and Tweaks section of the forum to discuss what you are trying to change, and may end up with something you prefer.

 

[Andre_Db66]

Can someone give an objective description of AR sound characteristic? Then maybe i can judge by that if my speakers are spot on or way off. Then perhaps i can also convince myself that it is not for me...

I know for a fact that whatever drives the AR speaker upstream is most decisive for the outcome.

Since a week or so i have changed my LST into AR3a in parallel, driven by a class D capable of 450 watt@2R. I have to admit this sounds fabulous and blows away the LST by miles... i find it very strange to read that when having LST in position 6 they sound mostly like 3a. What is the point of all the extra drivers when it just makes the sound less lineair.very noticeable on the class D amp. It does not sound even half as nice as the quad setup 3a.

So upstream is very influential and i guess i am still discovering what works... (for me)

 

[Aadams]

7 hours ago, Andre_Db66 said:

I have to admit this sounds fabulous and blows away the LST by miles... i find it very strange to read that when having LST in position 6 they sound mostly like 3a. What is the point of all the extra drivers when it just makes the sound less lineair.

AR designed the AR3a, AR5, LST and LST2 to have the same characteristic linear sound above 500hz, regardless of placement. They can sound very similar below 500hz if placed optimally in a room.  If you place them identically in a room as far as possible from boundary surfaces, say on a pedestal equidistant from floor and ceiling, they will sound practically identical when the attenuators are set to full or flat output. All of this assumes they are working properly.

If you follow the restoration guide and bring all of your speakers close to restoration goals including proper tweeters (Hivi or rebuilt originals) and foam woofer surrounds you will find the difference is the LST makes a lot more of the same sound as the 3a and 5 and is easier to place for optimum performance. 

 

 

 

 

 

[Andre_Db66]

Placed in the same position i find that the 3a produces bass more abundantly where the LST has more energy in the treble sectiin and the sound appears less flat. This is position 6 of attenuation. The 5 seems to have some sort of bump in the lower region which articulates the bass but is less deep yet more pronounced than the 3a. So i prefer the linearity of the 3a and 5 over LST. This in a situation possibly not ootimal with regatd to placement. Lifted from the ground, not against the wall, left side 4 feet from the walls in the corner and right side free space, no wall reflection. I found the LST to have the same kind of performance with bass as the 5 but also too much energy in treble area. I am thinking of seĺling the LST as i did the LST2. The 3a/improved and 5 are very agreeable speakers...

[frankmarsi]

Unless each speaker set is positioned in a room with the recommended methods universally adhered to, it will not be a fair platform for judging any speaker.

If poor quality program material and input sources are not of recommended preferences there again will not be a fair platform for judging any speaker.

With over 35 years of AR-LST ownership (3 pairs), I maintain that there’s only one best room placement that is recommended as optimum by AR Corp. That position is directly against the room’s front wall at about 27 inches high.  It's imperative that not in any setting it be placed mid-room or 3/4 out from the front wall.

As these speakers typically absorb more power than many other speakers, above average wattage is mandatory to enjoy their limits as typically, they just sound better the louder they are if correctly powered and positioned.

Input sources should also be of enough quality that a fair evaluation can be made. When these requisites are followed, the listener is that much closer to the ‘real’ musical event.

 

P.S. Regarding this post I started about the current separately available domes. About 15 or so years ago I posted here asking the same question about the available at that time tweeter domes. Most of them would not fit any AR tweeter in diameter and the post quickly faded away. I also brought up the question of rubber surrounds for woofers even though I knew the AR woofers operate at a certain compliance to achieve their excellent bass and rubber surrounds would rob them of that potential. It's become obvious 'mods' to the "Classic" AR speakers are were and are limited.

In my opinion the only apparent modification is using outboard auxiliary tweeters or tweeters that fit the inclosure hole or using rebuilt units but, there too power handling won’t be much higher than the originals. Although AR speakers were manufactured during a period when 10 to 35 WPC was the norm, only their mids and woofers are able to sustain the usage of higher power ratings and that’s only the larger models.

P.S. II, and to think I was seeing and living this while I was listening to my AR-3a's way back in 1971. The following year brought a SS  amp the ST-120 Dyna 60WPC and a AR-Xa turntable + Shure M55 cart.   So, can I have an Amen, if not, a Hey Man will do.........

https://www.youtube.com/watch?v=0g4zXepHASM

 

 

 

FM

 

 

 

 

 

 

1.2

 

 

 

[Andre_Db66]

Amen...

70's (absolutely horrible styling era...)

Only good or beautiful things from that period is some hifi equipment. That wood encasing started much earlier though, the same with speakers. The early period quality was much the same as the 60's however towards the end closing in on 80"s things turned for the worst. Much became over the top and commercialised.

Our home was engulfed with much of the design flaw shown in the video and it made a horrible home. It felt claustrophobic and gloomy. Dark colors from heavy wood kitchen and furniture mixed with chaotic colors and no room for contemplation or airy views. Everything was dictated by materialism and overcrowding. The opposite of less is more.

The LST make a very odd yet beautiful and wonderful appearance. However, it is not a common thing to have a room designed around their optimum placement. Recently there was a set on craigslist here where the tweeters had all received new vc. I would not dare to do this as it is obvious the only people interested in these speakers are purists and they will not accept this and move on. I believe FM is someone like this. I guess in his opinion placing refurbished originals at high cost is worth the while, because after having enjoyed them from way back in the 70's you would  want them to stay original.

As i mentioned before, a set of AR3a costing 450 does not justify this cost.

I do strongly believe however that if care is taken while restoring the originals and following the damping method and tinkering with the XO the result will come very close to original with low cost chinese vc from this topic thread. How far you go in perfecting this depends on skill and tools and time investment. I think that it is a much better alterative to HiVi tweeters or external super tweeters. The recently sold LST seems to prove my point. They sold below their value. Luckily my set of LST have everything original, only a recap of the XO with decent material. They will sell for a higher price, i am convinced of that.

About the rubber vs foam surround of the woofer. Compliance is probably off but it is not audible. Rubber surrounds are not for sale anymore and because i am trying to create a stacked set of 3a, for peace of mind and optical purpose i will most likely soon order a set of foam surrounds.

There will be an experiment with 4R voice coils as i have 2 magnets spare. The second set 3a i bought has much later tweeters in them and are missing the 3 point suspension.

I would like to place batting behind the dome however am clueless about sourcing this material...

[frankmarsi]

@ Andre_db66, the reply is not clear to me but, perhaps this post is going astray?

At this late date of AR classic speakers if you gave me a JBL L100 tweeter and assured me it'll sound just like an AR tweeter and wouldn't sound too hot or beamy as I recall those tweeters I'd be happy. I'd know they could handle the power I feed my system and they'd last. My sole affection for AR tweeters is that they were accurate with the additional wonderful wide spread of their output.

Since my first year of using AR-3a's, with-in the first six months, I  burnt out my first AR tweeter . They simply are not made to handle large amounts of wattage or clipping. Early on by 1972 I was using 60 WPC and even then they couldn't handle higher volumes. Although 60WPC couldn't handle AR-3a speaker loads if one prefers approaching higher and more realistic volumes anyway. 

Well,  that issue was solved by using outboard tweeters that could handle higher volumes and that latitude led me to feeding my 3a's even more power to the tune of 400WPC. I've been in that camp ever since.

After it all made sense to my young mind back then, I never looked back to the option of keeping my speakers original as to me it was like beating a dead horse. It was a sad realization for me.

Presently, I'm holding in reserve 16 AR-9 tweeters because I fear going back to 1972 and continuing proving the point that large volumes are not part and parcel of AR's original design parameters. One can't expect a little car's engine to propel it as quickly as a larger more powerful engine could. Although these days with the use of computer technology car manufacturers are getting as much power out of a small block engine whereas 40-50 years ago one could only enjoy the use of a big-block big horse power engine. Though AR speakers can't be compared to car engines, they're generally held back and still maintain their 70 year technology unlike the auto industry.

So, there we must remain unless one modifies their speakers to handle high wattage and for many here that's out of the question.  Whereas my choice was to elevate my use of AR speakers by using tweeters that can handle it. I don't feel I'm defeating the AR goal of accuracy as the audio band most tweeters typically operate at make it difficult to pin-point. Some tweeters are designed for different uses, my home use keeps me at a certain level of just that, home use. My amplifiers can easily entirely destroy my speakers but, I don't go to those limits.

If I were working in the large scale auditorium or stadium venue, I'd be installing tweeters designed to handle that sort of use. Many years ago, the horn designed for such use was able to do the job albeit and inescapably with some beaming and harshness thrown in too boot. I've used smaller horns for a short while 50 years ago but, found them uncomfortable to listen to, that's my opinion. Domes as AR upheld do a better job at least in the home application. I've seen certain domes that can handle large amounts of wattage, I'm just not certain of their sound quality so, for myself I keep it simple and stay away. Additionally, horns were designed for very far-field use, I for the life of me don't understand some folks using big horns for the upper frequencies in their homes as they must be fatiguing with long-term use but, that's another story.

So, I feel this thread has lasted as long as it can as it already has drifted far along since it started. We're going in circles as it is.

FM

@ Andre_db66, I've always felt a picture is worth a thousand words so, could you show a foto of your system and how it's arranged?