Good evening. I was wondering what tweeter would go with a fostex 8 inch full range driver? The ff225wk ones? I see fostex has horn tweeters but, man are they a lot of money! I like side domes but would worry they are not up to pair matching this driver? Please let me know what you think? Cheers Jeff
It depends on if you still have "ultrasonic" hearing capabilities - at 63 I do not, so, I dont have to worry about that part of the spectrum. I'd never hear it anyway; something to consider.
How and where, frequency wise, would you cross over to the tweeter, without disrupting the fullness and point-source 'ness of the Fostex full range driver? Cross low enough and you have just another 2-way speaker - losing any sonic beauty your Fostex driver brings to the table.
How and where, frequency wise, would you cross over to the tweeter, without disrupting the fullness and point-source 'ness of the Fostex full range driver? Cross low enough and you have just another 2-way speaker - losing any sonic beauty your Fostex driver brings to the table.
Hi. It looks like the full range driver drops of in db's at 7,000 khz. So I would leave the 8 inch full range and crossover the tweeter with a 6 DB at 7,000.
Cross over your Fostex at 2K & put an Aurum Cantus G3Si in there. Going past 2K with that FR Fostex gets you a rather unstable frequency, bobbing up & down some 10+ Db on its way up, not good. The 2K crossover puts the ribbon tweeter a tad above 95 Db...the same as the Fostex at that frequency.
Pay attention to driver spacing & placement on the front baffle...do up some nice radiused edges...should come out nice.
---------------------------------------------------------------------Rick..........
Pay attention to driver spacing & placement on the front baffle...do up some nice radiused edges...should come out nice.
---------------------------------------------------------------------Rick..........
its a shame Selenium's diffraction slot phenolic diaphragm tweeters have disappeared. Those had very even horizontal dispersion and even tho some of my titanium bullet tweeters measured better on axis all the way up to 20KHz, I tended to prefer the tone of phenolic.
There are some phenolic bullet tweeters at reasonable price which would match a Klipsch type front horn - their dispersion is roughly 40 degrees - don't know how they'd sound but subjectively Mike Chua thought the $20 JBL/Selenium ST200 sounded fine in a two way design of his from 4K up. There's a notch in the upper response. I'd imagine with a small cap rolled in around 10KHz (by theory) that it would add some useful treble to the power response. Going up in price to $40 (shipped) PRV offers a phenolic bullet tweeter which looks pretty good. Both of these tweeters can be re-built with the Selenium's replacement diaphragm only $6.99 (sans shipping)
here's some graphs of bullet type - I included the latest incarnation of Eminence's APT50 compression driver on their little round horn ($35)
There are some phenolic bullet tweeters at reasonable price which would match a Klipsch type front horn - their dispersion is roughly 40 degrees - don't know how they'd sound but subjectively Mike Chua thought the $20 JBL/Selenium ST200 sounded fine in a two way design of his from 4K up. There's a notch in the upper response. I'd imagine with a small cap rolled in around 10KHz (by theory) that it would add some useful treble to the power response. Going up in price to $40 (shipped) PRV offers a phenolic bullet tweeter which looks pretty good. Both of these tweeters can be re-built with the Selenium's replacement diaphragm only $6.99 (sans shipping)
here's some graphs of bullet type - I included the latest incarnation of Eminence's APT50 compression driver on their little round horn ($35)
My experience will link it to a super tweeter type tweeter that you can crossover with a single cap and cross about 10kHz. Capacitor value will probably be about 0.47uf to 2 uf.
So the tweeter can be a dome but choose a dome that is about half inch only. They typically will have very good high frequency response about 10kHz. When selecting choose based on sensitivity above 10kHz. It should be at least 90db and a good dispersion. Alternatively you can use a ribbon. Ribbons have excellent high frequency response but have issues circa 2kHz which is what people typically cross to in a typical set up.
I have used these tweeters and I think they should be fine.
VISATON SC5
Vistaton DT72
More pricey stuff
Aurum Cantus G2Si.
Beston RT003C
Oon
So the tweeter can be a dome but choose a dome that is about half inch only. They typically will have very good high frequency response about 10kHz. When selecting choose based on sensitivity above 10kHz. It should be at least 90db and a good dispersion. Alternatively you can use a ribbon. Ribbons have excellent high frequency response but have issues circa 2kHz which is what people typically cross to in a typical set up.
I have used these tweeters and I think they should be fine.
VISATON SC5
Vistaton DT72
More pricey stuff
Aurum Cantus G2Si.
Beston RT003C
Oon
Typically a FR is crossed to a horn so that one has comparable dispersion to the FR at the XO point. Ribbons & domes have much broader dispersion and they intoduce a big off-axis discontinuity.
Trying to get most ribbons to not be strained with a 2k XO is very difficut, and this approach means way more XO and XO parts. And the ribbon is going to be at least as pricey as decent horns.
The FT17 is Fostex’s cheapest tweeter but still $100+/pr.
Steve Creswell spent some time working to get tweeters to work with his FF225wk.
There is a simple tweak that works to smooth out the top of the FF225.
I have some FT17, the RS labeled Foster horn that it is basically a precursor of it (that is what i am going to use with my FF225 if someone does not talk me out of them), and some others, since i am moving out of hardware, cheap. email me if you want to check that out.
dave
Trying to get most ribbons to not be strained with a 2k XO is very difficut, and this approach means way more XO and XO parts. And the ribbon is going to be at least as pricey as decent horns.
The FT17 is Fostex’s cheapest tweeter but still $100+/pr.
Steve Creswell spent some time working to get tweeters to work with his FF225wk.
There is a simple tweak that works to smooth out the top of the FF225.
I have some FT17, the RS labeled Foster horn that it is basically a precursor of it (that is what i am going to use with my FF225 if someone does not talk me out of them), and some others, since i am moving out of hardware, cheap. email me if you want to check that out.
dave