The EMIT's In My Quantum 2's Are Weak...Likely Due To Age?

[MoreBeer]

I've noticed the EMIT's in my Quantum 2's are very weak which doesn't bother me that much as I also use a pair of small speakers along with them which are very bright to fill the void. Although I'd like to add some pop back to these.

I did replace the mids and mid bass with new, similar drivers that speced very close to the originals and that really helped in those ranges. I've also rebuilt the crossovers entirely. Everything is new on the crossovers with the exception of the inductor coils which check okay.

The solder contacts were reflowed which did zippo. I also tried bypassing the crossover and just used a cap that kicks in at about 3khz and they were still very quiet. All the sound is there...just not loud enough. The only way I can get what I think is normal output if to really pump up the highs with an EQ in addition to increasing the treble on the preamp.

I know the amp being used (Yamaha MX-1000) is okay as I hooked up other speakers to it and the highs are good. So I guess the tweets are just tired due to age. It would be strange for the magnets to weaken so I'm thinking the diaphragms are probably stressed in some way.

Anyhow, I'm obviously not concerned with the drivers in these to be original and just want them to sound okay as I put a ton of work into refinishing the cabs and the crossover rebuild.

I'm looking at Dayton PTC-8's as replacements? Good? Yes? No? Something else?

 

[MoreBeer]

Redo the originals. Yes, the EMITS are easy to damage.

Actually, they're not easy to damage.

And how exactly would one redo the originals? Sorry, but that's not possible.

I just sold the old tweets for $400...that was easy. So we're going new, one way or another.

 

[Mark B]

Have you measured the impedance of the EMIT's? http://audiokarma.org/forums/index.php?threads/emit-emim-tweeter-diaphragm-repair-how-to.65571/

 

[slimpikkins]

Wow, my Quantum 2 are not lacking top end at all. They are brighter then the QLS. Wonder what the deal was. Was their impedance around 4-6 ohm? The Dayton tweeters look nice to me but at 8ohm they may be a little muted but you won't know until you try. You might need to make a frame for them to fit in and mount it on the baffle.

The Quantum emits are very easy to take apart. Diaphragms could have been dirty or some other problem as I had one with magnet flaking with filings jammed in the clam, glad I didn't buy them on eBay...

 

[tubed]

+2
What's the tweeter array measurement?
Over 16 ohms?

 

[jazzmans]

since you've replaced/sold all the drivers, those aren't really infinity speakers any longer, and thus, probably don't belong here.

Good luck.

 

[Grenadeslio]

I've noticed the EMIT's in my Quantum 2's are very weak which doesn't bother me that much as I also use a pair of small speakers along with them which are very bright to fill the void. Although I'd like to add some pop back to these.

I did replace the mids and mid bass with new, similar drivers that speced very close to the originals and that really helped in those ranges. I've also rebuilt the crossovers entirely. Everything is new on the crossovers with the exception of the inductor coils which check okay.

The solder contacts were reflowed which did zippo. I also tried bypassing the crossover and just used a cap that kicks in at about 3khz and they were still very quiet. All the sound is there...just not loud enough. The only way I can get what I think is normal output if to really pump up the highs with an EQ in addition to increasing the treble on the preamp.

I know the amp being used (Yamaha MX-1000) is okay as I hooked up other speakers to it and the highs are good. So I guess the tweets are just tired due to age. It would be strange for the magnets to weaken so I'm thinking the diaphragms are probably stressed in some way.

Anyhow, I'm obviously not concerned with the drivers in these to be original and just want them to sound okay as I put a ton of work into refinishing the cabs and the crossover rebuild.

I'm looking at Dayton PTC-8's as replacements? Good? Yes? No? Something else?

The reason the Emits sound weak, you changed the Q by installing the WRONG drivers. As others have mentioned, you now have an abortion that belongs at the dump.

If you wanted to build speakers with Dayton drivers why not just purchase a kit from Parts Express and build something worthwhile?

 

[goodolpg]

Actually, they're not easy to damage.

And how exactly would one redo the originals? Sorry, but that's not possible.

I just sold the old tweets for $400...that was easy. So we're going new, one way or another.

I hope you disclosed they were "very weak" when you sold them.

 

[nyhifihead]

Also likely that the drivers he used were more efficient causing the emits to be lower output, relative to the rest of the drivers.

could also be interactions with the new crossover you made, iirc emits have a lower sensitivity than average

Regardless there are too many good DIY kits to arbitrarily chop up and retrofit existing speakers

 

[MoreBeer]

This "abortion" will likely blow away all the 40+ year-old Quantum's out there. Changing those mids and midbass drivers made a WORLD OF DIFFERENCE. So don't knock it till you try it. About the only worthwhile thing in these is the woofer. And I'll probably send these out for new cones and surrounds.

Regardless, I've been leaning towards newer gear lately. My Klipsch RF-7's and SVS 4000 subs just sound too damn good. Possibly THAT is the reason I think my Qunatum 2's sound like crap?

 

[slimpikkins]

i haven't heard it all but heard a lot of new and classic gear. Not much out there I would trade for my old clapped out Q2 for under a few grand. Sonic marvels...

 

[MoreBeer]

i haven't heard it all but heard a lot of new and classic gear. Not much out there I would trade for my old clapped out Q2 for under a few grand. Sonic marvels...

I agree 100%. $1,000 buys almost nothing exceptional in the new market. Especially if looking for larger floor standing speakers. But for about $2,000, great sounding speakers are doable. For example,I heard a pair of SVS Ultra towers recently which were fantastic. And at $2,000 for the pair, not crazy expensive.

My Q2's are only used on my vintage system. AKA, my "shits and giggles system" where I jerk around with cassette's, RTR and vinyl.

 

[MoreBeer]

FYI...those EMIT tweeters are 8 ohm. Three of them wired in series in the Q2's reads about 2.5 ohms or so, which both my banks read. So three new 8 ohm ribbon style tweets would match crossover specs perfectly.

As I don't need to tear the old EMIT's out now, what I'm going to do is buy the six new tweets and mount them to a plate, three per side without taking the old tweets out (at least initially) and rig something up where I can switch between the old and new. It will be interesting to compare the dramatic enhancement with the flip of a switch.

 

[jazzmans]

I like the dayton PT8 ribbons (really magnetic planar) I have three pairs of them.
But, they need a notch filter due to resonances you can see on the plot at PE.

They are the same tweeters Bob used in his sunfire speakers, and uses in his latest Amazing Line source.
How they'll match up to the modified Quantum crossover I couldn't guess.

 

[tubed]

This "abortion" will likely blow away all the 40+ year-old Quantum's out there. Changing those mids and midbass drivers made a WORLD OF DIFFERENCE. So don't knock it till you try it. About the only worthwhile thing in these is the woofer. And I'll probably send these out for new cones and surrounds.

Regardless, I've been leaning towards newer gear lately. My Klipsch RF-7's and SVS 4000 subs just sound too damn good. Possibly THAT is the reason I think my Qunatum 2's sound like crap?

Just about any speaker system, that I can think of, would sound like crap without properly functioning high frequencies.

I can't think of one speaker system I've heard could lead one to think of the Q2 as sounding "like crap" unless something is amiss

 

[MoreBeer]

After further consideration, I decided to leave them alone as its not worth screwing up the cabinets. And who knows, I might sell off all the vintage gear someday and would get nothing if I modified the cabinets which are perfect. I still do have the original mids and midbass drivers that all work and could be put back in if needed.

Overall, I'm probably being too critical of my 40 year-old Q2's. Comparing them to expensive new speakers and subs driven by new gear isn't fair.