OLA'S with different style woofers

[Andrew055]

Just picked up a nice set of OLA's, the wood cabinets are in great shape, but they have two different types of woofers. They both need to be refoamed. The elderly man I purchased them from said he was the original owner and had one of them professionally refoamed many years ago. But since they have two different woofer is that going to make a difference in how they sound or is it more of an aesthetic thing? I do have another pair of OLA's with the vinyl cabinets and they both have the woofers with the Masonite rings. I thought I could always swap one of those into these since they have nicer cabinets.  i realize that the refoaming procedure is different due to the foam surrounds are mounted differently on the mismatched woofers. Just more concerned if there will  be a difference in sound between the two.  

[Doug G.]

Yes, those look very nice. There won't be any perceptible difference in sound between the two woofers. After Advent stopped producing the Masonite woofers, they supplied the all-metal woofers as replacements.

As far as what to do with what woofers, are the Masonite woofers in the vinyl cabinets original to them. If so, I would have a hard time removing one to put into the walnut cabinet but that's just me. Instead, I would get one off eBay and install into the cabinet with the all-metal woofer. If the Masonites are not original to the vinyls, then I wouldn't have a problem swapping them around and if such silly things don't bother you, go ahead either way. Like I said, no difference in sound.

The installation method for the surrounds is different but they use the same ones, these days. Originally, the Masonite woofer surround had a wider outer flange but the ones made for the all-metal woofer with 1/8" flange work fine.

Masonite woofer - outer flange behind the Masonite ring - inner flange, in front of the cone edge.

All-metal woofer - Outer flange mounted on the little ledge on the frame - inner flange behind the cone edge.

Good luck, those look beautiful.

Doug

 

 

[Andrew055]

Thanks Doug for your information. Yes, the masonite woofers are original to the vinyl covered Advents. I like the idea of getting a matching metal one to go in the walnut cabinets instead. I think I will try to source one of the metal ones and then refoam the one I have.

[Doug G.]

I have one pair like that right now, too. They are very early ones from 1970 I bought from a guy originally from out east and his parents lived right down the street from Advent in the original location. He said they may have bought them right at the factory but wasn't sure.

Unfortunately, none of the drivers in them are original right now. Either his parents or he had them reconed with 12" plastic cones. They probably just needed refoaming but most people, years ago, weren't aware you could do that and just had a complete recone done. Actually the frames are original and I have them in case I ever run across some genuine Advent cone assemblies. The tweeters, which I also still have are the early ones with no grille/cage on them and one of the leads broke right where it goes into the dome edge.

So for now, they have Advent all-metal woofers and newer Advent tweeters in them.

One thing, if you use the all metal woofers, use a thicker gasket or Mortite (like on the Masonite woofers) to seal them as the original thin gaskets may not seal well enough. You don't of course,want any air leaks.

So, you can be assured that no matter which drivers you use, as long as they were made for the original Advents, they will sound the same, regardless.

Doug

[Norman Nicolai]

Hi Andrew. Please allow me to throw in my 2 cents on this topic. I have been working on Advent speakers only for the past 3 years. My knowledge is based on what I have read in this forum, other forums, and my personal experience. I did not own Advent loudspeakers “back in the day” when Henry Kloss started Advent, but discovered them late in life.

From what I have read the Masonite woofers were used in the Original Large Advents, the OLA’s. The woofers with the metal adapter were introduced when the New Large Advents, the NLA’s, came out a number of years later. NLA’s had a different sound from the original large Advents. The highs were not as rolled off and the bass was more pronounced. The NLA’s had a different woofer, a metal adapter instead of the Masonite, a different tweeter, a different crossover, and the speakers were positioned in the cabinet differently. (More about the crossover later...) The different sound of the NLA’s stemmed from all of the changes from the original speaker, including the new woofer and adapter. I’ve owned both speakers and to me the difference in sound was pronounced. The NLA’s sounded better playing rock, the OLA’s playing jazz and classical.

My overall point is that I think your two speakers should match. Different woofers with different adapters for the cabinet will sound change the sound. It might be that the difference is nominal and you may not be able to hear the difference at all times, but it will be there. If it were me, I would want the speakers to match.

You should also look at the crossovers in the 2 speakers. Advent went through a series of crossover changes in the original Advent speakers. Given that the woofers are different in the 2 speakers, you should check the crossover to confirm that they are similar. Plus the capacitors in the crossovers will be at least 45 years old and should be replaced. If not replaced, at the very least their values should be checked to confirm they are in range. If it were me, I would replace the caps. Even if the values are within range, and given their age, they won’t last forever.

Here is a site that you can use to identify the different crossovers that Advent used:   (Hat tip to JKent who originally shared it with me)

http://baselaudiolab.com/ADVENT_LA_XO.html

Good luck with your new speakers! I hope I haven’t confused things for you. One of the great thing about this hobby that I have learned is that there are very few “right” answers to problems. People hear thing differently and have different preferences. The point is to enjoy yourself and enjoy the learning process along the way.

[Doug G.]

Norman, I don't know what you mean by a "metal adapter". The driver frame, in each case, just mounts right into the cutout in the speaker board.

Both drivers use the same cone and the only real difference is a slightly greater excursion for the Masonite woofer. The Masonite ring was used to adapt a 10" cone to a 12"frame. While they were selling the original Advents, they developed the all metal frame to eliminate the Masonite ring. The surround fits right into the frame without the ring.

Differences in sound between the two models will be due to the change in crossover frequency (1000 Hz. to 1500 Hz) and possibly, the relocation of the woofer to get it closer to the tweeter for better driver integration. Also, in the original Advent, the woofer inductor is always in-circuit whereas in the New Advent, it is switched out of circuit in the "extended" position.

There is really no reason the two different woofers would sound any different used in the same speaker and I have found that to be so. There is also no reason the bass extension would be any different between the two speakers. The cabinet size is basically the same and they are both sealed. The position of the woofer on the speaker board doesn't matter.

Doug

[JKent]

Andrew,

I believe the foam roll on the masonite OLA woofer should be concave. Looks like your new one was refoamed incorrectly but the vinyl-clad ones look right.

If they were mine I think I'd put the good masonite woofers in the new veneered speakers after recapping them and use those, and get another metal basket one for the vinyl-clad speakers. There's one on ebay now for $55 OBO. Then sell the odd masonite woofer. 

Doug stated "The installation method for the surrounds is different but they use the same ones, these days. Originally, the Masonite woofer surround had a wider outer flange but the ones made for the all-metal woofer with 1/8" flange work fine". I'll just mention that I bought new foams from SpeakerWorks and they supply different ones for masonite vs metal. But the foams for the metal frame woofers can indeed be used (wish I'd known that before ordering). In fact, the metal frame surrounds may work better--it has a larger roll and is more compliant. Thank you RoyC for setting me straight on that.

Just a thought.

Kent