Are Advent and Advent/1 woofers identical?

[Guest ed]

I have been told that the woofers are identical in the Advent/1 and the New Advent Loudspeakers. As I refoamed I noticed that mine are not identical. The most obvious difference was that the magnets in one pair were square (Advent/1) and in the other round (the New Advent Loudspeaker). Also the wires that are connected to the cone front look different, The New Advent have wires coated with a dark material and the Advent/1 wires a clear coating and the wires can be seen as gold or copper. Are these woofers supposed to be identical? Have one pair of these speakers had the woofers replaced? Are they both original? If they are different then which pair is the original? I am not sure what I have now. Has anyone else noticed anything like this?

Thanks, Ed

[Doug G.]

Hi Ed,

The woofers in your "New Advents" have been replaced with later units. They should have square magnet woofers with an all-metal frame.

The ones in your Advent/1s are probably original.

Yes, they originally used the same woofers and, incidently, the same tweeters. The only difference was the cabinet size and crossover components (although I'm not absolutely sure about the latter).

Doug

[Guest ed]

>Hi Ed,

>

>The woofers in your "New Advents" have been replaced

>with later units. They should have square magnet woofers with

>an all-metal frame.

>

>The ones in your Advent/1s are probably original.

>

>Yes, they originally used the same woofers and, incidently,

>the same tweeters. The only difference was the cabinet size

>and crossover components (although I'm not absolutely sure

>about the latter).

>

>Doug

Thanks for the help. That is sort of a let down that the woofers have been replaced. At least they were a bargain from the thrift store. Maybe I will change the woofers from the between the pairs. Is there a way for me to find out what woofers I have in the New Advent speakers and verify if the Advent/1 are original? Is there a serial number somewhere?

Thanks again,

Ed

[Doug G.]

After I wrote my reply, I was thinking about this and I suppose it's possible that Advent used a later woofer in the last "New Advents" just as they used some of the all-metal woofers in the final original "Advent Loudspeaker" units that originally had the masonite woofers. I don't know.

Do your New Advents have any indication on them as to when they were built such as dates on the tweeters? Do they have serial numbers on the back of the cabinets?

Assuming they were replaced, the all-metal woofers used in the New Advents and Advent/1s have a nearly black frame and the frame is the "pincusion" style rather than round. They still have square magnets. Which leads to another question. Does it look like the existing woofers "belong" there or does it look like there was another type made to fit? This isn't definitive because a round frame unit could use the same holes if the spacing is correct.

The all-metal woofers I have do not have any date or serial numbers on them but there is a number stamped on the cone itself - 70554-002.

Whether they all had this number, I don't know.

I hope this helps identify your woofers.

Doug

[Guest ed]

Doug you asked some good questions so I investigated the speakers more. I removed the tweeter and woofer from each. First, there is not a date stamped on the outside of the tweeters but the back of the tweeter in the Advent/1 had a small yellow sticker on the back of it that appears to have "NOV 79" printed on it and the cone of the woofer of the Advent/1 has the same number that yours has (70554-002).

The New Advent did not have any date on the tweeter nor the number on the cone of the woofer that the other had. Also all of the stickers from the backs of the New Advents are missing, including the serial number. The baskets from both models woofers look the same to me. I am not sure what you mean by pincushion. The woofers do look to belong but I did notice that the foam inside of the New Advent has a square impression on it which seems to verify that these must be replacement woofers. Now I wonder what woofers they are. There are some numbers on the back of the magnet. There is 10-990-536 and below that is 2201721. There is also a number or mark on the cone. It is blurry and not clear but may be 11D1101, I am not sure. Any suggestions on how I can find out what these woofers are?

What would you do if you had these two pair of speakers? switch the woofers between the two so that the New Advents have the original woofers? Both pair are the utility cabinets.

Thanks for the reply and suggestions,

Ed

>Do your New Advents have any indication on them as to when

>they were built such as dates on the tweeters? Do they have

>serial numbers on the back of the cabinets?

>

>Assuming they were replaced, the all-metal woofers used in the

>New Advents and Advent/1s have a nearly black frame and the

>frame is the "pincusion" style rather than round.

>They still have square magnets. Which leads to another

>question. Does it look like the existing woofers

>"belong" there or does it look like there was

>another type made to fit? This isn't definitive because a

>round frame unit could use the same holes if the spacing is

>correct.

>

>The all-metal woofers I have do not have any date or serial

>numbers on them but there is a number stamped on the cone

>itself - 70554-002.

>Whether they all had this number, I don't know.

>

>I hope this helps identify your woofers.

>

>Doug

[Doug G.]

"Pincushion" refers to the shape of the frame or basket mounting surface. Instead of being completely round, it is basically round but the areas where the mounting holes are bulge out from the circle. The name comes from the shape of what a pincushion of the time looked like when viewed from the top.

I agree that the square impression in the foam stuffing in your New Advents indicates that the woofers were replaced at some point. The previous owner probably did this rather than have the surrounds replaced when they fell apart. It's too bad more people weren't/aren't aware of the surround replacement option.

It sounds like they are later Advent woofers from the period when Jensen owned the company (they bought Advent right after the New Advents and Advent/1s were produced). The 2201721 indicates this.

220 is the speaker code for Jensen. The other 4 numbers are supposed to be the date code but I'll be darned if I can decipher a date from those 4 numbers that makes any sense. Two of the numbers should be the year and the other two the week of the year. Pretty good bet that they weren't made in 1917 or 2017 :^).

Anyway, what I would do is try to get correct vintage woofers from eBay. The all-metal early era (square magnet)woofers are there quite often. I got some masonites on eBay to replace some all-metal ones that were in the Walnut originals I bought.

The two types are actually very similar except that the cones in the all-metal woofers are set back further into the frame. Some report that there is no difference in sound and some say they can hear a slight difference.

It may be that the replacement woofers in your New Advents may sound perfectly fine as I believe they are the same as the square magnet type except for the magnet shape. Do the cones look the same?

If they sound OK, replacing the woofers would then just be a matter of how much it bugs you to have incorrect woofers in them. This is why I wanted masonites in my Walnuts. Even though they sounded OK, I just wanted the correct vintage woofers in there.

Doug

[Pete B]

Do the round magnet woofers look like this which is a Legacy woofer.

I believe that this woofer mounts as a standard 10", if the woofer you have bolts into the oddball 12" pincushion pattern then it was probably just the evolution of that woofer. I'm wondering if it's similar to the Legacy woofer:

http://members.aol.com/basconsultants/ADV-LEG-W.jpg

[Guest ed]

I took photos when I had them apart. I photographed the back mainly for the number and the front. The back looks similar but the front is apparantly the pincushion design.

[Guest ed]

here is the front.

[Guest ed]

Doug, Thanks for the replies and help. The cones do look the same to me. The concentric grooves did not seem as pronounced on the back of the replaced woofer as on the back of what I think is an original from the Advent/1. It could have been my imagination I was not specifically looking for that.

[Doug G.]

Those are from the Jensen period. The 5002s and 5012s would have had that magnet style. They probably sound very similar, if not identical to the square magnet all-metal woofers.

I guess it's just a matter of listening and deciding whether or not they sound good. That, and if it bugs you enough that they aren't strictly correct :^)

Doug

[Pete B]

I agree with Doug,

I've been wondering for some time if there is a better large Advent

woofer. The cone edge and dust cap look the same, that's good.

The raised back plate should give this woofer more mechanical Xmax

before bottoming, a nice feature. But it's hard to tell if the

raised backplate is to compensate for say a thinner magnet, don't

know without measuring.

Ed, can you measure the DC resistance of this driver?

[Doug G.]

Pete,

Didn't they have to raise the backplate to compensate for the cone being recessed deeper into the frame on the all-metal units?

If you look at an original masonite woofer, you can see about a quarter of an inch of the VC sticking out above the spider whereas with the all-metal woofer, the bottom of the cone is pretty much flush with the top of the spider.

It is also apparent that the cone is deeper into the frame looking from the front.

Of course, I don't have a masonite free of a cabinet to look at at the moment so I can't compare the two frames for dimensions directly.

Doug

[Guest ed]

Pete, Thanks for the information. I am amazed at what you could tell from the photos. It would be nice to be able to identify the woofer from the numbers on the back. I am not familiar with how to measure DC resistance but I can take more photos :-)

[Pete B]

I have a pair of New Advent woofers, the all metal type, and they do not have a raised backplate, no I don't think they need it to equal the original. The cone is set back a bit further but it looks as if they took an equal amount off of the front of the voice coil, the cone just sits further back, the rest of the motor looks exactly the same as the original masonite type. The former is metal and the extra length in the original will provide a bit more heat sink area.

Now if the motor dimensions in this newer woofer are the same, and it has a raised backplate, then it will have even more mechanical Xmax, Nice!

One of the strengths of the large Advent was the large linear Xmax but also, very important, the allowance to go well beyond Xmax before bottoming. It's an excellent 10" woofer from this perspective, the raised backplate should make it even better.

I do recall reading with regard to Dahlquist DQ-10s that there was a later, improved woofer. I'd expect that this was it.

>Pete,

>

>Didn't they have to raise the backplate to compensate for the

>cone being recessed deeper into the frame on the all-metal

>units?

>

>If you look at an original masonite woofer, you can see about

>a quarter of an inch of the VC sticking out above the spider

>whereas with the all-metal woofer, the bottom of the cone is

>pretty much flush with the top of the spider.

>

>It is also apparent that the cone is deeper into the frame

>looking from the front.

>

>Of course, I don't have a masonite free of a cabinet to look

>at at the moment so I can't compare the two frames for

>dimensions directly.

>

>Doug

[Pete B]

>Pete, Thanks for the information. I am amazed at what you

>could tell from the photos. It would be nice to be able to

>identify the woofer from the numbers on the back. I am not

>familiar with how to measure DC resistance but I can take more

>photos :-)

Thanks for posting the question, and pictures. This is an

excellent find, that there could be an even better woofer.

I agree. it would be good if we could figure out what system

that woofer was designed for based on the numbers on the back.

We still would not know the exact parameters for the drivers,

but they could be measured. I'm going to try to find those

same woofers for measurement.

It would be interesting if we could get these dimensions for

the different versions of the Advent woofers, at least the ones

the involve motor performance. By the way this diagram is from

the Human EPI site: http://www.humanspeakers.com/

Just noticed that I would add, magnet thickness, back plate

thickness, pole diameter, voice coil OD, top plate ID, spider to

top plate clearance.

http://www.humanspeakers.com/diy/parts/images/dimensions.gif

[Pete B]

>here is the front.

Here's a picture from e-bay of what looks to be an original Advent/1, the cone, dust cap,

and edge look to be the same as the original masonite woofer. It looks very similar to

the picture that you posted:

http://www.snappymgr.com/images/items/1413.../14131773-5.jpg

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...AMEWN%3AIT&rd=1

[Doug G.]

Thanks for the pictures you guys.

I love the pictures of the old woofers with the original surround still there. Even though the surround is completely useless now, you can at least see the roll size and how it fit onto the frame.

I see a lot of the all-metal types with new surrounds installed and the flanges are really large with the roll being really puny, although we've established that the roll size, in itself, is not the most important feature.

Pete, I misunderstood what you meant by the backplate. I thought you meant the surface of the frame onto which the magnet is mounted and I wondered how the heck you could see it was "raised" by looking at the rear of the magnet!

I see now that you meant the rear of the magnet itself which has the bulge in it on the newer woofer.

Doug

[Carlspeak]

I've attached another woofer cross-section to suppliment Pete B's which may help explain the terminalogy used to describe the parts of a speaker. This one shows a vent at the back. Not all speakers have that feature. Manufacturers call that a vented pole piece. It helps provide air flow into the voice coil area to keep it from overheating.

Remember, it's all about the music

Carl

Carl's Custom Loudspeakers

[Guest gkentsmith]

I know I'm late getting into this thread, but if you haven't already done something, I have a number of the metal basket "New Advent" square magnet woofers. Like Doug, I replaced them in some Large Advents with the masonite ring type to restore them to original appearance and performance.

You can sometimes pick them up for around $35 a pair on the "other" site. Also, I have an over-abundance of these woofers and plenty of foam surrounds on hand. If you'd like, I can refoam a pair and sell them to you for $35 plus shipping. If you haven't already made a change, I think it makes a lot of sense to keep both sets of speakers in original condition rather than swap woofers.

Peace,

Kent

[Pete B]

Kent you probably noticed that we were looking at the 5002/5012

woofer above in this thread.

Do you know any details about the 5002/5012 woofer?

Details about the motor design, dimensions etc.?

Have you compared 5002 to the New Advent woofer from a subjective

standpoint?

[Doug G.]

A belated thanks to Carl for posting his cross-section picture too.

I meant to do this right after he submitted it but what is left of my once brilliant mind forgot to :^)

Doug

[Guest gkentsmith]

Pete,

I have listened critically to the Advent/1 versus the New Advent and found virtually no difference. I cannot say the same for the 5002 vs 5012. I've never had the opportunity to listen to these two models side by side. Sorry I can't give an informed judgement on that particular question.

Kent