i know that I'm not even near calculating the xover parts needed but i heard for the caps that film/foils are the better choice and air core inductors too. is there any brand that you guys would recommend, i was thinking Jantzen Audio for the inductors, i heard they were quite good.
Don't even think about aircore at the values needed for crossing a woofer down at 300Hz tho. Can your amplifier handle a 4R load easily?
The huge cost of large inductors is one of the reasons for me swapping to Bi-amping, as you can get used Behringer XO units very reasonable and modern solid state amplifiers are dirt cheap in comparison to copper costs. I use Jantzen as locally they are reasonably cost effective. I have no idea about costs in the UK tho for big inductors but here's a link to local Jantzen costs so you can do a comparison
https://speakerbug.com.au/index.php?route=product/category&path=18_45&page=2
The huge cost of large inductors is one of the reasons for me swapping to Bi-amping, as you can get used Behringer XO units very reasonable and modern solid state amplifiers are dirt cheap in comparison to copper costs. I use Jantzen as locally they are reasonably cost effective. I have no idea about costs in the UK tho for big inductors but here's a link to local Jantzen costs so you can do a comparison
https://speakerbug.com.au/index.php?route=product/category&path=18_45&page=2
can you explain what you mean be a 4r load. (are you talking about 4 ohm load?)
I'm not to worried about costs of inductors once its done im not going to mess with it.
I'm not to worried about costs of inductors once its done im not going to mess with it.
re:'i could set the woofer xover lower' - easiest place to crossover mid-woofer is at the baffle step frequency (115/ width in metres).
Re: Inductors - most cost effective for low frequencies are Jantzen Ferrite core, go for the largest wire gauge you can afford
Re: Inductors - most cost effective for low frequencies are Jantzen Ferrite core, go for the largest wire gauge you can afford
i cant get ferrite core jantzen where i am so its air core or iron core from jantzen. but its fine as i wont know what the values will be till i get the DAT to test the woofer then i will worry about cost
"R" is often used as the shorthand for Ohms.
What Pete said but remember that sometimes a wide baffle also sound better.
Personally I wouldn't worry about waiting until the DATS arrives to play with possible crossovers. Just use the old data from a 300mm Vifa woofer found on line and a even use any of the on-line XO programs to get an idea of what might work.
The online programs won't be accurate but will get you in the ball park. Then everything will be dependent on baffle size and all the other factors
What Pete said but remember that sometimes a wide baffle also sound better.
Personally I wouldn't worry about waiting until the DATS arrives to play with possible crossovers. Just use the old data from a 300mm Vifa woofer found on line and a even use any of the on-line XO programs to get an idea of what might work.
The online programs won't be accurate but will get you in the ball park. Then everything will be dependent on baffle size and all the other factors
I'm still in the process of designing what i want the box to look like and messing with volume but cos of the woofer the box will most likely be about 13 maybe 14in wide
and for the amp ya i think my amp can handle a 4 ohm load i don't think the speakers would hit that low impendence?
its puts out about 80watts RMS at 8ohm i think it does 140watts RMS at 4ohm. its quite old now but still puts out a punch i think its about 30 years old now.
and for the amp ya i think my amp can handle a 4 ohm load i don't think the speakers would hit that low impendence?
its puts out about 80watts RMS at 8ohm i think it does 140watts RMS at 4ohm. its quite old now but still puts out a punch i think its about 30 years old now.
I ask because if your amp is stable at low impedance loads you have the option to make the speakers 3.5 Way and cross one woofer lower to really boost the deep bass. You would cross the upper woofer electrical second at the baffle step and use a simple first order on the lower woofer somewhere around 80Hz.
30 Years is newish compared to my Kenwood that just died, it was 1976 or thereabouts.
My own 12" woofers sit in boxes ~650mm inches wide but the tops are separate and in boxes only 520 wide, skinny boxes are for WAF purposes sometimes, and I have no complaints about imaging. Doing so may possibly mean you might need a slightly more efficient [ louder] midrange than a 4inch tho, the Peerless 6" is a possibility then.
30 Years is newish compared to my Kenwood that just died, it was 1976 or thereabouts.
My own 12" woofers sit in boxes ~650mm inches wide but the tops are separate and in boxes only 520 wide, skinny boxes are for WAF purposes sometimes, and I have no complaints about imaging. Doing so may possibly mean you might need a slightly more efficient [ louder] midrange than a 4inch tho, the Peerless 6" is a possibility then.
ah ok, i think is stable but i would prefer to keep it above 4 ohms as its old and i want to easy on it. its an arcam 290 and 290p
You have both the integrated 290 and the 290P power amp?
If so why are you not considering Bi-Amping using a cheap external XO
If so why are you not considering Bi-Amping using a cheap external XO
i will bi amp but i haven't got the room to add an external xo or anything onto the stack, i can barely get stuff out plus its not just my leaving space
and i want to learn how to make an xover its why i started this project i want to learn more
and i want to learn how to make an xover its why i started this project i want to learn more
I bought some of these off ebay too for 25quid each . I found out they were used in a kef subwoofer
I bought some of these from ebay for 25quid they were used in the kef subwoofer 30b it was a quite small sealed subwoofer hope this helps somehow
so i took the woofer out of the box i put them in and although i did test them before i put them away i did not test the full stroke of movement and one out of the 4 rub at the near the bottom and top of the stroke.
so i peeled the surround off the chassis in hope to re-centre it can i cant do it without shimin the coil but i cant get the dust cap off as its one with the cone (the plastic coating used is is on with the dust cap) if i try to cut it off its just going to go though the cone or worse rip off the plastic coating, i have done that once nightmare lol.
anyone got any suggestions on how to re-centre the voice coil with out taking off the dust cap? (its a really thick paper dust cap)
I've done it many times just not without shimin the coil.
so i peeled the surround off the chassis in hope to re-centre it can i cant do it without shimin the coil but i cant get the dust cap off as its one with the cone (the plastic coating used is is on with the dust cap) if i try to cut it off its just going to go though the cone or worse rip off the plastic coating, i have done that once nightmare lol.
anyone got any suggestions on how to re-centre the voice coil with out taking off the dust cap? (its a really thick paper dust cap)
I've done it many times just not without shimin the coil.
Hi Callum. Interesting. I too bought 4 off these 12" Vifa. I did wonder who bought some more! I have measured one in DATS. Quite low Fs, maybe 26Hz IIRC but also quite low QTS. I was hoping to use mine in a dipole/ripole/slot loaded set up. A pair per channel. At 4 ohms each the usual woofer parallel wiring will be 2ohms obviously and so only good for simple class D or otherwise serious solid state amp.
Regarding your rub, you have 6 holes on the mounting pcd so you get 5 goes at biasing the gravity effect on the VC. Can you 'balance' it out? Shall have to measure mine more closely to check for this. Assume you've used the Rub test in Dats for this .?!
Regarding your rub, you have 6 holes on the mounting pcd so you get 5 goes at biasing the gravity effect on the VC. Can you 'balance' it out? Shall have to measure mine more closely to check for this. Assume you've used the Rub test in Dats for this .?!
its much worse than i thought i took of the dust cap so slowy near perfect but once i saw under it i died on the inside. the coil was lop sided i got an image but in the process of taking the spider glue off to look whats going on under it ill update you after
these are new old stock from 2001 (thats was it says on the vifa sticker on the box it came in) so this came from factory like this uhh
uuuuhhhhh. well i will have a go fixing it and i feel like i can do it with a ruler some epoxy and some surround glue. um mabe some thing small and round to smooth out that dent that may have been when i was testing it.
ah and a small knife to get the coil of the cone
idk where the coil is meant to sit but imma guess its the length the leads are at and i think i can see a slight glue line.
i have done a redone before that did require me to take out a coil with out damaging the cone.
Its like 12:30 in the morning
wish me luck
So the voice coil former isn't level in the cone? Can't really tell from the pics? I better test my 4. I was going to say the seller has a few left but having just checked they've gone.