New tweeter needed.

[planet10]

Factory Tweeters

BTW factory tweeters can still be had from your Boston dealer -- talk about supportting your installed base! Price here in Canada is $70 each (should make them about $40-45 each in the US). Of course it is the only thing recommended ;^)

I say go for the Vifas, and learn a bit about XOs. And starting now start shoping for your next project (get input from your wife on what it should look like). And you don't have to think rectangular box -- everyone i showed these to, loved the shape.

An externally hosted image should be here but it was not working when we last tested it.

dave

 

[gsattler]

so that's what those speakers look like....pretty crazy looking. Prash, I can understand why your wife doesn't like 'em too much.

 

[planet10]

so that's what those speakers look like....pretty crazy looking. Prash, I can understand why your wife doesn't like 'em too much.

Those are what the toobz i built look like, a Boston A70 is a little rectangular box, wider than it is deep.

And the women in particular liked the shape of the toobz -- i still have to build my mom a pair.

dave

 

[Thatch_Ear]

Dave,
Your toobz remind me of something Shahinian was doing only not round. Same angle and set up on the top though. Yours probably sound better too. I do like them better without the sox on. Thatch

 

[Thatch_Ear]

Prash,
What is the impedence rating in ohms for the speakers. Also pull a tweeter out and see how large a magnet is on it and decide how much engineering you want to do on the cabinets. I did some poking around and found all kinds of posts from the past on A70s but no efficiancy ratings etc. It is pretty important to match the SPLs so that you have a good balance between tweeter and woofer. Also it would be helful to know if there is an L-pad in xover to adjust the tweeter level. Also know that if your woofer is rated at 8 ohms you can still use a tweeter rated at 4 ohms but your xover will have to be rebuilt with a 4 ohm high pass. While your digging around inside the cabinets check out the type of wires that are in there. That is an area that was in the cost cutter, bean counter's crosshairs, and is a good thing to replace when upgrading the crossover parts. Cables, interconnects and interior speaker wiring seem to be a weak point in the DIY community.
Thatch

 

[prash]

planet10, I saw the design on your website, it looks quite good.
I will check out the Vifas.

The A70s are an 8 ohm speaker with 90 dB/W/m sensitivity. 15-75W power rating, 1" copolymer diaphragm ferro fluid cooled tweeter, 8" paper cone woofer, acoustic suspension type speaker. One of the best speakers I have heard, this means that either I have not yet heard very good speakers or that these speakers were really really good for their time 🙂.
I haven't looked at the xover yet, not sure if it has tweeter adjustment.

 

[Thatch_Ear]

I went through the selection at Parts Express and what seemed like a good match was the Audax TWO25AO 1" soft dome for $20.50 ea. 91 db, SPL 8 ohm, and goes down to 1K so the cross at 2.5 K aught to work out great. The surround kit is # 260-920 and $21.90 so 2 tweets and woofer repair will run you $62.90 plus shipping. Replacing the capasitors if the cross is a 12 db slope 5.6 mF Dayton Metalised Prop add $4.20. Not bad at all when you consider what $75 would get you at Circuit City.

 

[prash]

I went through the selection at Parts Express and what seemed like a good match was the Audax TWO25AO 1" soft dome for $20.50 ea. 91 db, SPL 8 ohm, and goes down to 1K so the cross at 2.5 K aught to work out great. The surround kit is # 260-920 and $21.90 so 2 tweets and woofer repair will run you $62.90 plus shipping. Replacing the capasitors if the cross is a 12 db slope 5.6 mF Dayton Metalised Prop add $4.20. Not bad at all when you consider what $75 would get you at Circuit City.

Thank you so much. So a 91 dB is ok considering that less than 3dB difference will not be detected by our ears as affecting the tonal balance? Is this correct?

thanks

 

[Thatch_Ear]

I am sure that like everything else there are tolerances built in. By the time you figure everything else in on top of how much the drivers might vary from what is given as specs I doubt it would make enough difference to notice. Course I am just going by what info I could pull up and have never heard these tweets. They could be too bright for your tastes and you might need an L-pad to adjust the brilliance. I have some tweets in my closet that sounded good with a tube amp but when the speakers became the rear channels and got hooked up to some older SS they were too bright and I put another type in. The long cheap cables could have a lot to do with it too.

 

[prash]

Is the audax tweeter the better one from the others in the same price range and specs on parts express? I saw other models from Peerless, Morel etc. Just curious.

thx

 

[planet10]

Is the audax tweeter the better one from the others in the same price range and specs on parts express? I saw other models from Peerless, Morel etc.

I don't think you can right out and say one is better -- there are a wealth of very competitive products out there (and particularily in that price range). One might be better in a certain application, with a specific XO.

dave

 

[Thatch_Ear]

I looked at the specs given, the type of dome and what was given as the low for the drivers. Giving price on top of that I based what my choice would be mainly on the fact that it was a soft/ semi soft dome and with matching impedence and very close efficiancy ratings. The big selling point to me was how low you could cross at. Some of the others were rated right at 2.5K and when you take into consideration tolerances in the crosses and not knowing about the rest of your system I thought the extra room in the specs would allow for the tweaking that might be needed to get a seamless transition from woof to tweet. Your options are much greater with these tweets than the others in a price range that seemed reasonable for a possible learning experience that might have no gain in listening pleasure. I do of course expect that this will be an improvement over the distorting drivers. How much better could well rely on future tweaking of the crossover or felt rings around the tweeter or some other fun problem. Since you have us and it is your money, I consider the gamble to be well worth it.( laugh now) We look foreward to the outcome. Yes that was the royal we, or I have a tapeworm.

 

[prash]

I ordered the audax tweeters from PE. The vifa ones had different impedances and diff sensitivities which I did not want to experiment with right now. I guess this is a good exercise for now. There will hopefully be more projects in the future for me and to have some fun. I will keep you posted on this one anyway.

Thanks a lot for your help guys. This forum is different from the other forums I have been in.

😉

 

[bostarob]

Maybe for your next project try the vifa's. They sound good and have nice smooth roll off's, good for crossover design.
good luck!
-andy

 

[avhed]

Thank you so much. So a 91 dB is ok considering that less than 3dB difference will not be detected by our ears as affecting the tonal balance? Is this correct?

thanks

When I turn the treble control up 1 db, I can easily notice it.
I am also looking for tweeters for my A70s.