20 replies to this topic

[KlausDK]

I found a pair of new tweeters, i may have found a pair of woofers (can someone recommend OEM replacement or must i find a real original speaker ?)

Hi Philippe

Why do you need new drivers? If you want the best sound from your 18B, it is important to use original drivers. If it is only the foam surround failing on your woofers, it can easily be replaced.

If the woofers are destroyed/damaged beyond repair, I might have a set of the original woofers for AR 18B, but they might also need to be refoamed, I will have to check the parts number when I get home, it should be something like 1210037-0, according to the 1986 parts list in the library.

BRgds Klaus

[johnieo]

Also does someone here have the schematical diagram of the crossover for the AR18B ? I searched on the site and could'nt find it.
Philippe, Paris, France

Hello Philippe:
Voila, the crossover for the AR-18b -18s

Cheers,

Attached Thumbnails

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[KlausDK]

I will have to check the parts number when I get home, it should be something like 1210037-0, according to the 1986 parts list in the library.

Hi Philippe

It is the 1210037-0 I have, they are in good working condition with OK foams. Pls let me know if you are interested

BRgds Klaus

[KlausDK]

Dear Philippe

If you want to be sure to have the correct AR-18B sound, you should use 18B components, also the woofer since the cross-over frequency for the woofer relies completely on the natural roll-off of the driver. I would not advise to change the cross-over either, I think the simplicity of the AR-18B cross-over is an important reason for the excellent sound, this speaker is reputed with.

The woofers I have are not new, and I do not know how old they are; I found them in a set of AR-6 (where they definitely do not belong). Therefore, I cannot tell you how long the foam surrounds will last, but probably like 2-5 years, also depending on how much UV-light they will have. Again, if you have the correct and working woofers from your speakers, a refoam would fully restore the function of your woofers.

If you are stiil interested, send me an email

BRgds Klaus

[johnieo]

Do you think the result could be improved by using the 18 BX crossover diagram ? :
Philippe, Paris

Hello Philippe:

Please do not change the crossover circuit or change either the woofer part number or the tweeter part number. I would be best to use the woofers offered by Klaus.

A very long time ago someone, I believe it was Steve F., posted comments about the relative merits of the AR-18 series. The poster indicated that the AR-18bx is the next to the lowest in quality of the series, with the AR-18bxi considered ti be the lowest quality. The AR-18bx used a generic tweeter, and a lower quality woofer than was used in the AR-18b. Further, the crossover frequency was increased to 3,000 Hz, widening the range over which the woofer was asked to speak. Also, the AR-18bx use an AR-1200068-0C woofer, which was stated to be not as good sounding as the woofer used in the AR-18 or -18b.

In a nutshell, the AR-18b has both good sounding woofer and tweeter, which are matched to its crossover, so it would be prudent to replace parts with original AR-part numbers, and retain the same value crossover capacitor. It's a nice sounding speaker; I have several and enjoy their sound. It is worth the effort to maintain their authenticity.

Hope this helps,

[johnieo]

Regarding the tweeters, mine appear to be working but are smashed and deformed so i found these original AR parts on Ebay the box is labelled HR 1 1/4" and 200014-3
I made a search on this site and found that the tweeters for the 18 models are HR (high range) 1 1/4" # 1200014-3
I assume that they dropped the #1 on the box label, because if you look at the 1986 listing you will notice that every reference starts with a 1
What do you think ?

Philippe

Hi Philippe:

Before you purchase new tweeters, I would try to pull the dome out to about its original position - either with a small flexible plastic hose and a bit of vacuum, or with a sharp pin and lift carefully. If the voice coil is good and you can get the big dents out, then I am told it is not necessary to replace the tweeters.

The #1 in front of the part number was added by AR at some point to allow for more part numbers.

My AR-18 tweeters are part number 200014-3. I think these are what you see listed on eBay.

My AR-18b tweeters are part number 200034-0, but the AR parts list gives their number as 200038-0. I think both numbers are correct.

Why not try to work the tweeter domes back into approximate shape gently. If they sound good, why replace them? Either refoam the woofers or obtain a pair from Klaus. If you purchase his pair, someone will purchase your pair and refoam them - so don't throw them away! These drivers cannot be replaced.

Cheers,

[Diamonds&Rust]

i will follow you and not change anything unless i am sure of what i am doing

John's advice is the best anyone can offer.

I would hurry to take advantage of Klaus's offer.

Bret

[kkantor]

Hello Philippe:

Please do not change the crossover circuit or change either the woofer part number or the tweeter part number. I would be best to use the woofers offered by Klaus.

A very long time ago someone, I believe it was Steve F., posted comments about the relative merits of the AR-18 series. The poster indicated that the AR-18bx is the next to the lowest in quality of the series, with the AR-18bxi considered ti be the lowest quality. The AR-18bx used a generic tweeter, and a lower quality woofer than was used in the AR-18b. Further, the crossover frequency was increased to 3,000 Hz, widening the range over which the woofer was asked to speak. Also, the AR-18bx use an AR-1200068-0C woofer, which was stated to be not as good sounding as the woofer used in the AR-18 or -18b.

In a nutshell, the AR-18b has both good sounding woofer and tweeter, which are matched to its crossover, so it would be prudent to replace parts with original AR-part numbers, and retain the same value crossover capacitor. It's a nice sounding speaker; I have several and enjoy their sound. It is worth the effort to maintain their authenticity.

Hope this helps,

I don't remember seeing this thread, but I totally concur. The original 18 was a great speaker. Its biggest weakness was that the tweeters blew a lot. This problem, no doubt, was compounded by the 18's affordable price, which meant it tended to show up in dorm rooms, etc, driven much harder than originally expected. Also, at this time, amps were starting to get more powerful. Later versions of the 18 were attempts to increase tweeter longevity, at the expense of the elegance of the first iteration.

The 18 is also an important product, IMO, because it represented a conceptual shift in AR's general approach to product development. Prior to the 18, AR's product development philosophy was always purely "top down." Flagships were established, then technology and ethos trickled down to low price points in subsequent models. The 18, in contrast, really set the standard by which the 28, 38, 48, etc, were judged.

-k

www.kenkantor.com
www.ztamplifiers.com

[Diamonds&Rust]

i will follow you and not change anything unless i am sure of what i am doing

Ken's rarely wrong... <grin Ken, it's o.k.>

I would hurry to take advantage of Klaus's offer. If you don't, I might.

Bret

[johnieo]

Also the values are not exactly 5 microfarads but 4,7, should i combine differents values to obtain exactly 5 ? Maybe this is a question for John ?
Philippe, Paris

Hello Philippe:

All of the comments I have seen from crossover designers say that +/- 10% is fine. In fact most of the electrolyic are +/- 20% so 4,7 would be fine for a 5,0 uF.

Hope this helps,
John

[Steve F]

John,

I'm quite impressed and most flattered that you are citing such an old post of mine.

It dates from Feb 18, 2003.

Here it is again:

"Hi Guys,
Here's the info that I think you're looking for:

The original 18 was essentially an AR-7 with the liquid-cooled version of AR's superb 1 1/4" cone tweeter. It had a crossover frequency of 2000Hz, the same as the 7, but with the new tweeter's greater power handling capability, the 18's power response was somewhat flatter than the 7. The 18 was a truly exceptional small speaker and a great match for the 9.

The 18s was pretty much the same, save for some slight cosmetic differences, and is also highly recommended.

The 18B had a bull-nosed vinyl cabinet , the same 1 1/4" cone tweeter, 2000Hz crossover, but the tweeter was now centered on the baffle above the woofer, instead of being offset as in the earlier 18's. The woofer also changed, and used a shiny black plastic dustcap.

The big change took place with the switch from the B to the BX series. The cabinet got bigger (from 6 5/8" deep to 8 1/4" deep), and the tweeter changed from that great original AR-built 1 1/4" cone to some randomly purchased 1" dome. The crossover went from 2000Hz to 3000Hz, with the expected roughening in power response that physics predicts with an 8" 2-way system.

The BXi was similar to the BX, but the crossover rose to 3200Hz. The BX and BXi had stated LF -3dB points of 52Hz vs. the older 18's 62Hz, indicating a change in the design intent for these speakers to a more full-range design.

The 18 or 18s is the model you want. The 18B is ok, but stay far away from the BX and BXi."

Steve F.

[Robert_S]

The 18s was pretty much the same, save for some slight cosmetic differences, and is also highly recommended.

The 18B had a bull-nosed vinyl cabinet , the same 1 1/4" cone tweeter, 2000Hz crossover, but the tweeter was now centered on the baffle above the woofer, instead of being offset as in the earlier 18's.

A minor AR-18/18s information supplement/correction!

The tweeter placement change, from offset to centred, was seen in the transition from the AR-18 to the AR-18s.

Also, the capacitor value changed: 6 uF for the 18, 5 uF for the 18s. The 18s used the 200038-0 tweeter (featuring S-shaped leadouts for "added protection during peak power surges"), the 18 had the 200014-3 (also seen in the AR-7x).

Incidentally, having both UK and USA assembled models of the AR-18s, I was surprised to see a difference in the cabinet width: USA made are 255 mm wide, UK are 244 mm.

The AR-18s remains a 'cult classic', here in the UK, and is still much sought-after for use as a near-field studio monitor, by those 'in the know'.

Robert_S

[johnieo]

John,

... that you are citing such an old post of mine.

It dates from Feb 18, 2003.
Steve F.

Steve: I date from 1937; cut/paste is necessary to remember things correctly

Cheers,