Replacing mid drivers in the 2B

gmcman

I figured since the stock drivers have 25 years on them, I might as well pick up a set and at least see how they compare. Not knowing the history of the speakers also came into this decision. I was actually surprised to see how they were packaged and thought that more care would have been given but they seem to have survived., not the way I would have packaged them.

I will take room measurements before and after and also right at the speaker. What distance from the speaker is ideal to measure with REW for the speaker itself?

mopar paul

Unless there is obvious damage to these, I would spend my money on the tweeters and crossover upgrades. Magnet shifting can be a problem on the mid drivers but can usually be very obvious. I'm sure others will chime in that have more knowledge than me.
Remember these drivers were very high quality rubber surrounds and I would bet most guys on here use those "25 year old" drivers to this day!

gmcman

Thanks for the suggestions, sorry but I should have stated that they have already been TL modded, with fresh caps. I agree they still sound good, just looking to see (or hear) what a fresh set of drivers may provide. If no different then I at least have a spare set.

F1nut

If they work, there's no reason to replace them.

gmcman

The originals look fine, surrounds appear to be in great shape. What gave me the itch was the fact the left speaker has a slight pop when playing at moderate levels with some good bass going through them. I have enough sense to turn it down when I start to hear this but it always seems to be in the left speaker.and is very seldom. Also with kids around I want to have a spare set just in case.

The fact I have them I want to give them a test, doubtful I will hear any differrnce but it's worth some experimenting time.

Likely I will remove them and place is safe keeping. As far as taking a sweep measurement for just the speaker, not the room....what is the best way to go about this?

TennMan

Swap the drivers from one speaker to the other. If the pop follows to the other side one of the drivers is at fault. If the pop stays on the same side your amp could have a capacitor breaking down or some other problem.

F1nut

What gave me the itch was the fact the left speaker has a slight pop when playing at moderate levels with some good bass going through them.

In that case, you do have a bad driver.

Mr. Bubbles

I have not tried any of the newer replacement drivers and have had the same thoughts you seem to have. I am anxious to see any measurements you take. At the same time i agree with the others here enough to where i have not tried this myself. I would also say that F1 could be right or wrong depending on how you interpret it. I have seen many drivers simply accumulate wear over the years which weakens the spiders, surrounds, etc and they seem to pop prematurely but work perfectly otherwise. definitely bad when compared to original specs but not truly defective when compared to other old drivers in similar situations. This however is the exact reason I have wondered about what you are trying. i llok forward to seeing your results.

PolkieMan

Yes I am curious too.
I could see replacement drivers being better since some manufacturing processes are better now than they were back then.
But it could go the other way as pride and quality on somethings is not like what it used to be.

gmcman

When I was using one AVR I would get a pop, then it followed to the second AVR. With the ST-202 it would pop on occasion but with the 200.2 it doesn't pop as much, could be the higher damping factor or just cleaner circuitry. Switching to the right speaker makes sense but I'm fairly certain it's the driver, does aid in the evaluation though, but between 2 AVR's, 2 pre's, and 2 amps it's still there.

Don't get me wrong, the speaker plays just fine even at levels I don't care to listen to. Only issue I have is with heavier bass from R&B or the likes and again it's at a fairly high volume which I tend to avoid knowing about the issue. Some tracks with a lot of stringed bass instruments it's just slightly muddy, very slight and I was looking to chase resonances but this is why I want to try a new driver first.

I'm very curious as to the results myself.

Schurkey

I'd be looking for cabinet air leaks.

F1nut

It's a bad driver, seen it more than a few times. It's actually not a pop, it's a slap/crack noise as the driver bottoms out on heavy bass notes.

gmcman

I wasn't able to get any sweeps done tonight, after Shurkey mentioned a possible air leak naturally I couldn't just say "it's fine" without actually going in and investigating. I will go back and apply Armacell as I start pulling the drivers but I did apply a dense type of sealing strip and I can't remember which but it resembles Armacell..just can't remember off hand.

The passive radiator test on both speakers reveal a 3-4 second time period for the mids to return to their stationary point, not outstanding but not too terrible. With the mids pushed in and a firm push on the passive, revealed a very slight leak at the tweeter, hard to hear unless I turned the HVAC off and my ear is against the tweeter. I resealed and the passive test remained the same, just wasn't substantial enough to change the push test but nonetheless a leak is a leak.

I did remove the left dimensional driver and this really told a story. No scratching when pushed in but it's very weak, almost no effort to fully collapse the driver. I took the new 6511 and gave it a push and it was night and day...actually took a little effort. The stereo driver was almost as bad, deceiving when in the cabinet but when removed there's almost no resistance when pushing on them.

F1nut wrote: »

it's a slap/crack noise as the driver bottoms out on heavy bass notes.

That's exactly the noise, like an acetylene torch pop.

I understand that too large of an air leak can cause drivers to over-extend but these drivers are very weak.

F1nut

That's exactly the noise, like an acetylene torch pop.

That's it. The driver is shot, time for a new one. End of story.

Mr. Bubbles

If you decide to dump the old drivers let me know. I need a couple of 6511's for a pair of 1C's that use a smaller cabinet per driver and should address some of the compliance issues with the old worn drivers.

F1nut

That cabinet volume theory is flawed. I had one in a CRS+.

gmcman

I went ahead and changed all the MW's out, all of them were very weak. Thing is, the speakers sound fantastic with the old drivers in. I can take the pre to -5 using the B&K 200.2 with a somewhat heavy bass song and they sound great, add in some Marley and then the popping starts.

I replaced the drivers and played them for awhile, I can say for certain that the bass is tighter. The bass string is no longer a droning hum but a vibrating string. I did turn them up on the same Marley track and there is no more popping in the left, I did take it up pretty high to the point I started hearing some slight distortion which was +3 on the pre, ( I don't normally run it up past -5, let alone 0) right when I went to turn it down there was a slight pop on the right from being overdriven but nothing too harsh. I don't ever listen to them at that level so I'm satisfied I could be playing some Bob Marley at those levels with no issues....no way could I get them that loud before.

I'm not trying to ruin a new set of drivers but needed to know I could at least play them at the 12 O'clock position.

Now I will change out the .5 mills to a .2 and experiment further, the 198's definitely sound padded down now.

gmcman

Mr. Bubbles wrote: »

If you decide to dump the old drivers let me know. I need a couple of 6511's for a pair of 1C's that use a smaller cabinet per driver and should address some of the compliance issues with the old worn drivers.

I will let you know for sure. Right now I'm going to hold onto them just in case anything arises from the new ones.