First, I would like to thank everyone for their responses. On to the heart of the matter. I have an old pair of HK Forty speakers in which the foam surrounds are toast on the woofers. I am going to save the cabinets for a later project but for now, I have pulled the tweets out and looking to do a simple 2 way system. The tweeters that HK put in these cabinets are Vifa D25TG-55. From what I have researched, these are very similar to the Vifa D26TG-05. (Here is the spec sheet for these http://www.madisound.com/pdf/vifa/d26tg-05-06e.pdf). Budget is more of a concern now for myself as I'm sure it is for many of you. I would like to not put more than about $25.00/ea. into the woofers. I know, not much to work with. But then, the tweets are not much either. Here is a list of the woofers I have been looking at in no particular order:
Silver Flute W17RC38-S4, 6.5" 4 ohm Shielded Magnet Wool Cone http://www.madisound.com/catalog/product_info.php?cPath=45_228_256&products_id=1354
Goldwood GW-6PC-4 6-1/2" Heavy Duty Woofer 4 Ohm http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-307
Dayton DC160-8 6-1/2" Classic Woofer http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-305
Vifa TP16WJ-06-08 6-1/2" Woofer 8 Ohm http://www.parts-express.com/pe/showdetl.cfm?Partnumber=299-277
Doing the crossover isn't an issue. I will probably go BI-amped as I already have everything I need to do so. Passive may be an option as I have a fair assortment of caps and coils.
I guess my biggest issue is not being able to hear what any of these woofers sound like. Or, how they will match up with the Vifa tweeter. I have been able to in the past match drivers together fairly well but I was always able to hear them first. This isn't the case here. So, with the deepest respect of the people who do this more than I here, I an asking for their advice on what to get. If there should be (I'm sure there is) other choices out there that will fit into the budget and match well with the Vifa tweet, by all means, pass it along, I am not at all locked into the ones I have mentioned.
Thanks once more for any and all answers in helping me make a choice here.
Ken
Silver Flute W17RC38-S4, 6.5" 4 ohm Shielded Magnet Wool Cone http://www.madisound.com/catalog/product_info.php?cPath=45_228_256&products_id=1354
Goldwood GW-6PC-4 6-1/2" Heavy Duty Woofer 4 Ohm http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-307
Dayton DC160-8 6-1/2" Classic Woofer http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-305
Vifa TP16WJ-06-08 6-1/2" Woofer 8 Ohm http://www.parts-express.com/pe/showdetl.cfm?Partnumber=299-277
Doing the crossover isn't an issue. I will probably go BI-amped as I already have everything I need to do so. Passive may be an option as I have a fair assortment of caps and coils.
I guess my biggest issue is not being able to hear what any of these woofers sound like. Or, how they will match up with the Vifa tweeter. I have been able to in the past match drivers together fairly well but I was always able to hear them first. This isn't the case here. So, with the deepest respect of the people who do this more than I here, I an asking for their advice on what to get. If there should be (I'm sure there is) other choices out there that will fit into the budget and match well with the Vifa tweet, by all means, pass it along, I am not at all locked into the ones I have mentioned.
Thanks once more for any and all answers in helping me make a choice here.
Ken
Hi,
First off the crossover is always an issue or its oversimplified and
wrong. The Vifa looks very good value but no measurements.
If you cannot take measurements using unmeasured drivers is
a lottery and you will not get it right unless you are very lucky.
Despite what the suck it and listen brigade say .....
If you go that route the Vifa looks by far your best bet.
(Though with all those holes it ain't going to look too pretty)
The Goldwood / Dayton midrange quality is not up to much IMO
and some SF drivers have large (crossover controllable) peaks
before their treble roll-off.
The alternative is not to base the design around an old tweeter,
(refoaming the bass drivers of the originals seems your best bet).
Then you can use published designs but none will approach your current budget.
I would search around all the forums for someone who has
(or is planning) buying the vifa drivers and intends to take
some frequency response plots.
Or try this :
http://www.acoustic-reality.com/ar-sxo2.htm
/sreten.
http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://www.geocities.com/woove99/Spkrbldg/DesigningXO.htm
http://www.zaphaudio.com/
http://www.rjbaudio.com/projects.html
http://www.geocities.com/woove99/Spkrbldg/
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://htguide.com/forum/forumdisplay.php4?f=39
http://www.humblehomemadehifi.com/
First off the crossover is always an issue or its oversimplified and
wrong. The Vifa looks very good value but no measurements.
If you cannot take measurements using unmeasured drivers is
a lottery and you will not get it right unless you are very lucky.
Despite what the suck it and listen brigade say .....
If you go that route the Vifa looks by far your best bet.
(Though with all those holes it ain't going to look too pretty)
The Goldwood / Dayton midrange quality is not up to much IMO
and some SF drivers have large (crossover controllable) peaks
before their treble roll-off.
The alternative is not to base the design around an old tweeter,
(refoaming the bass drivers of the originals seems your best bet).
Then you can use published designs but none will approach your current budget.
I would search around all the forums for someone who has
(or is planning) buying the vifa drivers and intends to take
some frequency response plots.
Or try this :
http://www.acoustic-reality.com/ar-sxo2.htm
/sreten.http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://www.geocities.com/woove99/Spkrbldg/DesigningXO.htm
http://www.zaphaudio.com/
http://www.rjbaudio.com/projects.html
http://www.geocities.com/woove99/Spkrbldg/
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://htguide.com/forum/forumdisplay.php4?f=39
http://www.humblehomemadehifi.com/
I planned on using the HPF part of the original HK crossover. HK says this is a 2.2khz Asymmetrical 4th order Butterworth. I would guess that I would need a woofer that stays together till about 2khz. The BI-Amp thing was kinda a last minute thought.
I went to Zaph Audio's web site and found the 6.5"-7" comparison chart here after posting the OP. It would appear that the Dayton DA175-8 7"
Zaph's chart
or the (budget permitting) Dayton RS180S-8 7"
Zaph's chart
Would be better routes to go. If for no other reason than, like sreten said, there are graphs for each and you can see what they will do. I still want to run both of the Dayton woofers names above through the WinISD program and see what kind,size enclosure will work. 1+ cu. ft. will be getting larger than I have space for.
I went to Zaph Audio's web site and found the 6.5"-7" comparison chart here after posting the OP. It would appear that the Dayton DA175-8 7"
Zaph's chart
or the (budget permitting) Dayton RS180S-8 7"
Zaph's chart
Would be better routes to go. If for no other reason than, like sreten said, there are graphs for each and you can see what they will do. I still want to run both of the Dayton woofers names above through the WinISD program and see what kind,size enclosure will work. 1+ cu. ft. will be getting larger than I have space for.
I used WinISD on these 4 woofers. The Vifa, Dayton DA175, and Dayton RS180 both 4 and 8 ohm. Here's what I came up with
All are in a 1cu. ft. box. As you would expect, all would like a larger enclosure and would improve in varying degrees. I adjusted the tuning freq. on each to get the best curve from each.
I wish I could find a response chart on the Vifa. That would really help alot. I also considered replacing the surround on the original woofers but the cost would be similar to replacement.
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All are in a 1cu. ft. box. As you would expect, all would like a larger enclosure and would improve in varying degrees. I adjusted the tuning freq. on each to get the best curve from each.
I wish I could find a response chart on the Vifa. That would really help alot. I also considered replacing the surround on the original woofers but the cost would be similar to replacement.
Here's what they had at the mfg website. Both discontinued, but datasheets available.
http://www.tymphany.com/files/products/pdf/P17WJ-00-08.pdf
http://www.tymphany.com/p17sj-00-08
Peace,
Dave
http://www.tymphany.com/files/products/pdf/P17WJ-00-08.pdf
http://www.tymphany.com/p17sj-00-08
Peace,
Dave
You're quite welcome. Glad to help. Another thing to note, in regards to replacing the foam surrounds on your current woofers. If the cones, spiders and voicecoils are ok, you can find replacement foam surround kits in ebay pretty reasonably. I bought some a couple years ago from seller GeoAliWil for less than $20 for a pair. The kit included instructions, surrounds, glue, shims, etc. The only things you need to provide yourself are a knife, table and workbench, and good lighting.
Peace,
Dave
Peace,
Dave
Thanks again. The only place that I knew about was SpeakerRepair.com and they are wanting about $38.00 shipped for a pair. I figured I could get new woofers for just a bit more. I'm juts not sure of my ability to get the surrounds on correctly so that the voice coils don't rub. The other thing is that I know one of the 4 original woofers is blown. 2 of the originals are beyond repair (spiders are fubar) so that leaves 2. One of which may very well be the one that's blown. With the surrounds gone, it's impossible to move the cone straight up and down to hear if the coil is rubbing or not. It would be a crap shoot and not worth taking the chance on. BUT......for less that $20.00/pr. it may be worth trying.
Hello again, There are even cheaper sources for speaker surrounds, and possibly other parts, but as you said, you're not sure if you are up to it. I liked the kit I got from the ebay sellers I mentioned because it came with just about everything you need for a pair of drivers, and the instructions are very clear, with good pictures. They even offer discounts if you by larger quantities of surrounds.
If the woofers are as far gone as you say, it may just be cheaper to source new ones. The problem you run into is compatibility with the enclosure you have and the high frequency drivers, as was mentioned by others earlier.
Peace,
Dave
If the woofers are as far gone as you say, it may just be cheaper to source new ones. The problem you run into is compatibility with the enclosure you have and the high frequency drivers, as was mentioned by others earlier.
Peace,
Dave
I just took a look at what GeoAliWil has on eBay. WOW. I do have a pair of known good old school Lanzar car subwoofers that could use new surrounds. Given the price of current subs that would be equivalent in quality, those would make for a good candidate to try it out on.
I am also considering upping my budget from $25.00/ea. to $40.00-$50.00/ea. I know this will open up alot of possibilities to use with the Vifa tweets.
I am also considering upping my budget from $25.00/ea. to $40.00-$50.00/ea. I know this will open up alot of possibilities to use with the Vifa tweets.
Hey Thump Lump, I do have to admit that I'm not familiar with the particular speakers you have. Is there a way you could post pics of the damaged drivers and the speakers cabs. I'm curious to see what they look like and the condition of the woofers. Also curious to see if there are any identifying marks on the woofers.
Peace,
Dave
Peace,
Dave
Here are pics of the cabinets, tweeter and woofer. The markings on the tweeter are D25TG-55 6ohm. It is from this that I figured they are Vifa. The woofers on the other hand, I have no clue. On the back of the magnet is printed C36 3 795 B2. As you can see in the pics, I have removed and cleaned the surround from the woofers. It was while I was doing that, that I began to think it would be better just to replace them. Which is why I started this thread. The baskets are stamped steel and FWIW...the old surround was very tacky when it was coming off. Not dried out like I would have thought it would be.
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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Upon doing some more research at Zaph Audio's website, I came across the Mach 5 Audio MLI-65. This looks like it may be the best compromise between performance and what my budget allows. Although, I still like the Dayton RS180-4 or even the Dayton DA175. Thoughts?????
The tweeter is fairly decent, I've used a pair before. Resonance is at around 2000hz, but its almost non existent, in that it's very very well damped. This has the knockon effect of allowing you to cross closer to the resonance without it being as much of a headache.
I did a design where the crossover was around 2200hz, but here the response is 33dB down by 1000hz. Plus the system is never played very loud (its in the kitchen where my mum uses it), nor would I encourage it being played loud.
What this means is that I would not recommend it be paired with the dayton drivers, what with them having metal cones and generally requiring lower crossover points.
I'd be thinking 3khz 4th order for guaranteed safety.
sreten said...
And I cannot agree more. Without the ability to measure, especially when working with a short bandwidth tweeter, and most likely as close as you can to its lower limit. Success will most likely be limitted.
In my opinion what you're after is a paper/poly coned driver with an appreciable upper range, with a well controlled upper breakup.
I did a design where the crossover was around 2200hz, but here the response is 33dB down by 1000hz. Plus the system is never played very loud (its in the kitchen where my mum uses it), nor would I encourage it being played loud.
What this means is that I would not recommend it be paired with the dayton drivers, what with them having metal cones and generally requiring lower crossover points.
I'd be thinking 3khz 4th order for guaranteed safety.
sreten said...
And I cannot agree more. Without the ability to measure, especially when working with a short bandwidth tweeter, and most likely as close as you can to its lower limit. Success will most likely be limitted.
In my opinion what you're after is a paper/poly coned driver with an appreciable upper range, with a well controlled upper breakup.
Ok....Forget the Daytons. After looking what seems like hours on end at well over a dozen woofers, I think I have narrowed it down to these two. The Mach 5 MLI-65 and the Fountec FW168. Both links lead to mfg. T/S and freq. response sheets. More info can be had here at the Zaph Audio site with more complete charts and both woofers listed. Just click on the appropriate model number for the proper info. Being a relative noob to all this, each appear to work out to 4khz before they start breaking up real bad but, I'm no expert at reading these charts so you tell me. The Fountec does have an aluminum cone like the Daytons but, it appears to not break up as early as they do. Which would be the best value for the $$$ MLI-65 ($36.00) or the FW168 ($45.15) ?
The FW168 is a better driver, but requires a crossover around 2khz at the minimum to make the most out of it.
See the issue with metal cone drivers isn't the breakup (ringing) they exhibit, in this case the double peaks between 5 and 7.5khz. But how this impacts the distortion further down the line. You will notice that the 3rd and 5th order harmonics peak also, but at around 2.5 and 1.6khz.
This is why zaph recommends a 2khz 4th order or lower crossover, something that your tweeter wouldn't be too thrilled about.
Even if you were going to cross higher, the double peak breakup would require some serious work to get it out of harms way.
The MLI's distortion isn't great, but the one thing it does boast is a smooth roll off, making it far easier to work with.
See the issue with metal cone drivers isn't the breakup (ringing) they exhibit, in this case the double peaks between 5 and 7.5khz. But how this impacts the distortion further down the line. You will notice that the 3rd and 5th order harmonics peak also, but at around 2.5 and 1.6khz.
This is why zaph recommends a 2khz 4th order or lower crossover, something that your tweeter wouldn't be too thrilled about.
Even if you were going to cross higher, the double peak breakup would require some serious work to get it out of harms way.
The MLI's distortion isn't great, but the one thing it does boast is a smooth roll off, making it far easier to work with.
I'm thinking that I would use the original x-over that came with the HK Forty's. According to their specs, it a 4th order Butterworth at 2,200. From there, all I would have to do is to build one for the woofer. The other alternative is to bi-amp. The active x-over I would use there has independent x-over points, level and phase switch. I'm thinking this would be the better way to go than passive.
I also have pretty much decided on the MLI-65.
I also have pretty much decided on the MLI-65.
I suggest going with those Vifa woofers:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=299-277
And trying the existing crossover first - you might get lucky, not that it's likely, but you might...
I say that, because, if those Vifa woofers have the same response as the Vifa P17-WJ woofers then they would be the easiest to make a crossover for as they have a fairly smooth top end roll-off and not much hf breakup.
I'd buy some of them myself, but I've got so many drivers that I need to use already...
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=299-277
And trying the existing crossover first - you might get lucky, not that it's likely, but you might...
I say that, because, if those Vifa woofers have the same response as the Vifa P17-WJ woofers then they would be the easiest to make a crossover for as they have a fairly smooth top end roll-off and not much hf breakup.
I'd buy some of them myself, but I've got so many drivers that I need to use already...
I believe I am. I haven't ordered anything yet except for a few things from Digi-Key for testing purposes. Namely a Panasonic WM60AY electret mic capsule and the associated parts for the DIY measurement mic. And a 1% 10w resister for T/S measurements. Beside having a few woofers here that I have no clue as to their T/S parameters, I can use the mic for getting a FR out of the Vifas. In the end, there was something about Mach5 Audio that just turned me off. They seemed to be more car oriented and not able to provide much support if needed. Granted, the Vifa is rather unknown from a specs point of view but, at least Vifa is a reputable company.
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