See your not really getting much useful help here in general. 
Always good to have a think about what we are dealing with here...that Focal woofer seems to be a bit of a house speciality in glass fibre sandwich construction.
That is the usual progression of behaviour in midwoofer cones which need increasingly complex bass filters to get a good rolloff. I'd reckon I've got the bass exactly right with the 5kHz notch on what is evidently the third type in your case.
The 94mm 4 ohm Vifa XT19 tweeter is not really a marriage made in heaven IMO, but we are having a bash.
Dissi was a bit vague there, but he does seem to see a problem getting the XT19 loud enough. So what to do? My inclination is to still go with the third order filter I suggested here:
http://www.diyaudio.com/forums/multi-way/234913-didnt-get-right-4.html#post3477182
This IS diyaudio, and most of us are prepared to fiddle about a bit to get things right. If it's a complete disaster, there are plenty of 94mm 8 ohm tweeters about that might work better.
Visaton DT94 Mylar
SEAS 19TFF
The 4uF and 0.25mH tweeter components will be adaptable with some cheap wirewound resitors, so you won't be up ship creek without a paddle for sure.
Always good to have a think about what we are dealing with here...that Focal woofer seems to be a bit of a house speciality in glass fibre sandwich construction.
An externally hosted image should be here but it was not working when we last tested it.
That is the usual progression of behaviour in midwoofer cones which need increasingly complex bass filters to get a good rolloff. I'd reckon I've got the bass exactly right with the 5kHz notch on what is evidently the third type in your case.
The 94mm 4 ohm Vifa XT19 tweeter is not really a marriage made in heaven IMO, but we are having a bash.
Dissi was a bit vague there, but he does seem to see a problem getting the XT19 loud enough. So what to do? My inclination is to still go with the third order filter I suggested here:
http://www.diyaudio.com/forums/multi-way/234913-didnt-get-right-4.html#post3477182
This IS diyaudio, and most of us are prepared to fiddle about a bit to get things right. If it's a complete disaster, there are plenty of 94mm 8 ohm tweeters about that might work better.
Visaton DT94 Mylar
SEAS 19TFF
The 4uF and 0.25mH tweeter components will be adaptable with some cheap wirewound resitors, so you won't be up ship creek without a paddle for sure.
thanks Steve, I'm going with the last schematic you drew and the values you selected. Let me check out what's available over here and if there is a question, I'll get back to you tonight. Thanks for the effort and time. I am getting the hurry-up and get this off the living room floor and put it together look for W/A..... In looking at the woofer the 3.3 resister stays correct?, and how much can I vary the microfarads in the tweeter if the stores don't have the exact value? Steve I am reading something I am not sure of so I'll ask a nubbie question. I have a 1.5mh 20 AGW P core inductor, but what is the .30 ohm reading? thanks again...
Honestly, Danny, the component values aren't all that critical. Get within 10% on capacitance and you are doing alright, even 30% on coil resistance.
I do notice that Dissi has disrupted the thread and then run away giggling like most of the others, so perhaps we should discount his feeble "contribution".
But for all that, I do now slightly favour my own below circuit as being better and more adaptable with resistance adjustments, even if the impedance slightly sucks.
I do notice that Dissi has disrupted the thread and then run away giggling like most of the others, so perhaps we should discount his feeble "contribution".
But for all that, I do now slightly favour my own below circuit as being better and more adaptable with resistance adjustments, even if the impedance slightly sucks.
Attachments
An externally hosted image should be here but it was not working when we last tested it.
Oh, Steve, forgot but thought you might be interested in this software: here is a link I think, or this one Jeff Bagby's Loudspeaker Design Software, which has interesting specs. Steve, what program did you use for my crossover? thanks again
Yup, I don't have MS Excel, so Jeff's software is out of the question.
I use Visaton Boxsim:
Downloads
Like most tools, it's knowing how to make it sing and dance that is the trick. I learnt its basics in an hour, and regard it as mathematics with a visual output.
In my observation, there are really only three types of bass and two types of tweeter, so I can do some reasonable guesswork with it.
Sadly Visaton don't provide any decent polycone drivers, so I mostly work with paper bass. But great software. I've had a great time exploring filter topologies, mostly trusting Lynn Olson as a general guide.
I use Visaton Boxsim:
Downloads
Like most tools, it's knowing how to make it sing and dance that is the trick. I learnt its basics in an hour, and regard it as mathematics with a visual output.
In my observation, there are really only three types of bass and two types of tweeter, so I can do some reasonable guesswork with it.
Sadly Visaton don't provide any decent polycone drivers, so I mostly work with paper bass. But great software. I've had a great time exploring filter topologies, mostly trusting Lynn Olson as a general guide.
You lose the 12 ohm resistor next. After that you increase the bafflestep coil to 2.2mH which lowers the midrange another 2dB.
Losing the 2.2 ohm series resistor on the tweeter takes the HF impedance too low, IMO, so not an option.
After that, well, it's time to try a more efficient tweeter...
Losing the 2.2 ohm series resistor on the tweeter takes the HF impedance too low, IMO, so not an option.
After that, well, it's time to try a more efficient tweeter...
yes, the original info I got from Focal was the ideal or optimum size was .9 cuft. However, with my bracing and "floorboards" its around .7 cuft. You are right about impedance as my Martin Logan Ascents can drop to 1.2 ohms and a cheap amp would not handle that without serious problems........thanks for your input
Hi Audio4him,
Proper crossover design requires the exact knowledge of cabinet dimensions, port dimensions and the positions of the drivers on the baffle. Any info on that? A picture usually helps very much to know what we are talking about.
Your tweeter is about 3 dB louder than the woofer. If you are willing to accept an impedance of 4 ohm in the upper frequency range, there shouldn't be a need to buy a more efficient tweeter. The major problem of your driver combination is the crossover frequency. The tweeter doesn't allow to go lower than 3 kHz, and the woofer is difficult to handle above 2 kHz. Both drivers require a notch filter, no way to succeed with a simple crossover.
Proper crossover design requires the exact knowledge of cabinet dimensions, port dimensions and the positions of the drivers on the baffle. Any info on that? A picture usually helps very much to know what we are talking about.
Your tweeter is about 3 dB louder than the woofer. If you are willing to accept an impedance of 4 ohm in the upper frequency range, there shouldn't be a need to buy a more efficient tweeter. The major problem of your driver combination is the crossover frequency. The tweeter doesn't allow to go lower than 3 kHz, and the woofer is difficult to handle above 2 kHz. Both drivers require a notch filter, no way to succeed with a simple crossover.
finished speker
thanks to all that helped from all sites; here is the finished speaker which will replace the mantel and will be the center channel for one of my main systems, and also the system for my computer aided by an integrated amp with equalizer. I won't go into all the individual speakers as most of us recognize them or can read the posts in this thread. The crossover turned out to be a combination of many of the examples used from this site and others, and the vent also adjusted on the back. The Paradigm and JBL subs were not pictured and neither were the Martin Logan Ascents as I did not build them (bummer, having trouble with image)
thanks to all that helped from all sites; here is the finished speaker which will replace the mantel and will be the center channel for one of my main systems, and also the system for my computer aided by an integrated amp with equalizer. I won't go into all the individual speakers as most of us recognize them or can read the posts in this thread. The crossover turned out to be a combination of many of the examples used from this site and others, and the vent also adjusted on the back. The Paradigm and JBL subs were not pictured and neither were the Martin Logan Ascents as I did not build them (bummer, having trouble with image)
Attachments
ABOVE: the two l/r vertical speakers used Vifa tweeters and Aura 6" woofers to be used with my t.v. The horizontal 9 unit speaker is my center channel with a 2way l/r computer system built with Focal woofer and Vifa tweeter; the center channel uses a HiVi tweeter with Peerless mid (M&K) and Madisound woofers. The mantel above the center speaker will be removed and this 7" long, 100lb speaker replacing it. The old Sony will go into one of the bedrooms and a 65" plasma (Pan or Sam or Sony 4K) will be placed on top; while a new fireplace goes underneath.... like a mans castle should be ! thanks everyone...all the best to you and yours
I got a PM from Danny saying he was struggling to post a schematic of the final article, but what he ended up with was more or less this circuit:
http://www.diyaudio.com/forums/multi-way/234913-didnt-get-right-4.html#post3477989
Not clear if the bafflestep was increased to 2.2mH, but that is easily done to reduce woofer midrange level. The attenuator was tweaked to 3 ohms series and 16 ohms shunt but it sounds like levels worked out OK on the Vifa XT19.
That is the usual 3kHz flat baffle second order crossover and the 5kHz notch on a 6" woofer. I'm starting to think we have pretty much a formula for two ways with a 6" bass.
BTW, you use the paper clip function in the reply box to upload an image.
http://www.diyaudio.com/forums/multi-way/234913-didnt-get-right-4.html#post3477989
Not clear if the bafflestep was increased to 2.2mH, but that is easily done to reduce woofer midrange level. The attenuator was tweaked to 3 ohms series and 16 ohms shunt but it sounds like levels worked out OK on the Vifa XT19.
That is the usual 3kHz flat baffle second order crossover and the 5kHz notch on a 6" woofer. I'm starting to think we have pretty much a formula for two ways with a 6" bass.
BTW, you use the paper clip function in the reply box to upload an image.
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