HI!
SO I have googled like mad and really am having trouble finding a good MTM or TMM crossover for some Vifa P17's I have. I would like to turn them into LCR for the theatre room and would love to find a good design for them or even if anyone can help with a crossover design! I have found loads of dead links so hopefully someone has some x-over schematics and box designs on their hard drives?
Here's the fun part, Tweeter choice is open. On hand I have d25's and d26's as well as HIVI ribbons(RT1.3) and even some non shielded XT25's I can use. I do NOT need to use these and will consider other options including compression drivers, small widerange drivers or other tweeters! I can build the boxes no problem and size is not constricted at all as they will be behind an acoustically transparent screen. Power is from a large audyssey equipped Denon HT receiver so they must be passive please(no active FAST type designs etc using a wideband)
Will be 90% used for movies as it is a dedicated room but obviously sound quality is important. Mainly want the MTM for the SPL benefits so a variable BSC circuit would help as they will be close to a wall.
I have also chosen an MTM to try and keep vertical dispersion a bit narrow as the roof and floor are both hard surfaces(no carpet) but the walls will be treated at first reflection points etc.
Bass is provided by a Dayton 15" Ultimax in a huge sealed enclosure so they only 'need' to go down to maybe 60hz. I can change the subs to 4 vifa M26WR or up to 4 JBL 2226(all drivers in my cupboards) if I need the crossover to be a little higher.
Any suggestions of good designs out there?
SO I have googled like mad and really am having trouble finding a good MTM or TMM crossover for some Vifa P17's I have. I would like to turn them into LCR for the theatre room and would love to find a good design for them or even if anyone can help with a crossover design! I have found loads of dead links so hopefully someone has some x-over schematics and box designs on their hard drives?
Here's the fun part, Tweeter choice is open. On hand I have d25's and d26's as well as HIVI ribbons(RT1.3) and even some non shielded XT25's I can use. I do NOT need to use these and will consider other options including compression drivers, small widerange drivers or other tweeters! I can build the boxes no problem and size is not constricted at all as they will be behind an acoustically transparent screen. Power is from a large audyssey equipped Denon HT receiver so they must be passive please(no active FAST type designs etc using a wideband)
Will be 90% used for movies as it is a dedicated room but obviously sound quality is important. Mainly want the MTM for the SPL benefits so a variable BSC circuit would help as they will be close to a wall.
I have also chosen an MTM to try and keep vertical dispersion a bit narrow as the roof and floor are both hard surfaces(no carpet) but the walls will be treated at first reflection points etc.
Bass is provided by a Dayton 15" Ultimax in a huge sealed enclosure so they only 'need' to go down to maybe 60hz. I can change the subs to 4 vifa M26WR or up to 4 JBL 2226(all drivers in my cupboards) if I need the crossover to be a little higher.
Any suggestions of good designs out there?
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I actually have a pair of JV60's (which is where most of the drivers are from ) and another pair made into bookshelves.
The JV60 noticeably beams at around 2.5-3k horizontally before the tweeter is at full swing around 3.5k. They ARE pretty good and have done an ok job so far. Just want to improve them a bit.
The lower woofer is also low-passed quite low making it a 2.5 way for baffle step correction. This isn't really helping with their backs close to the wall as I don't really need much if any BSC. I'd rather a couple of db more in sensitivity if anything.
I would also like to gain the better vertical control of the d'appolito arrangement and a lower crossover point would be great if possible.
How did LSK have theirs set up? Anyone have a schematic of the crossover they used?
) and another pair made into bookshelves.The JV60 noticeably beams at around 2.5-3k horizontally before the tweeter is at full swing around 3.5k. They ARE pretty good and have done an ok job so far. Just want to improve them a bit.
The lower woofer is also low-passed quite low making it a 2.5 way for baffle step correction. This isn't really helping with their backs close to the wall as I don't really need much if any BSC. I'd rather a couple of db more in sensitivity if anything.
I would also like to gain the better vertical control of the d'appolito arrangement and a lower crossover point would be great if possible.
How did LSK have theirs set up? Anyone have a schematic of the crossover they used?
JV60 is definitely D25AG aluminium 1"
I only have 4 M26WR's so at best could make MTMW or something but would be limited to 88db sens of the M26. Should be able to manage a solid 90-92 with 2 P17's in parallel and little to no BSC? I figure 3 MTM's and 4 M26's as subs would make a nice all Vifa system(I love old school Vifa by the way )
D25's will do 2.5K as I've found projects that have used them successfully this low but crossover details are non existent!
I'm not an accomplished crossover designer so whatever I come up with will no doubt be fairly flawed. I also have no means of measuring speaker drivers etc
A good TMW design using the above would be cool for LCR also if there's a good design(I can't find one anywhere). If it's a nice design I could live with the lower sensitivity as I could run the xover very low and the Dayton 15 would just do very low bass.
For surrounds I will just keep some Jamo Bipoles I have(surround 200) which do a good job and look presentable so I'd like to use up these drivers for LCR
I only have 4 M26WR's so at best could make MTMW or something but would be limited to 88db sens of the M26. Should be able to manage a solid 90-92 with 2 P17's in parallel and little to no BSC? I figure 3 MTM's and 4 M26's as subs would make a nice all Vifa system(I love old school Vifa by the way
)D25's will do 2.5K as I've found projects that have used them successfully this low but crossover details are non existent!
I'm not an accomplished crossover designer so whatever I come up with will no doubt be fairly flawed. I also have no means of measuring speaker drivers etc
A good TMW design using the above would be cool for LCR also if there's a good design(I can't find one anywhere). If it's a nice design I could live with the lower sensitivity as I could run the xover very low and the Dayton 15 would just do very low bass.
For surrounds I will just keep some Jamo Bipoles I have(surround 200) which do a good job and look presentable so I'd like to use up these drivers for LCR
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It's easier than you think. You can convert a straight two way to an MTM by wiring the basses in series, and doubling inductance and resistance on the bass filter, and halving capacitance. Double the box volume and ports too. Simple as that!
The polycone Vifa P17 and D25AG are one of those famous old combinations that works with little effort.
Our own John Kreskovsky designed a complex filter for it years ago. The build link is broken AFAIK, but I saved the details. Marshall Leach did a simpler one: Vifa 2-Way Loudspeaker System
The polycone Vifa P17 and D25AG are one of those famous old combinations that works with little effort.
Our own John Kreskovsky designed a complex filter for it years ago. The build link is broken AFAIK, but I saved the details. Marshall Leach did a simpler one: Vifa 2-Way Loudspeaker System
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I'll be interested to see what you do with the M26's if you use them (though I only have two). Mine are in 70L crappy boxes with tuning I wouldn't go for now that I know a bit more Still waiting for me to get off my butt and order parts to complete my active crossovers so I can run them with my MTM's
There are a lot of "rules" with MTM's but they are generally if you want the original D'appolito style. I just made sure my mids were as close to the tweeter as I could get (helped by my driver combo being time aligned without much trickery) and went with a 4th order accoustic slope, in my case at 2.8Khz.
Theres a lot of mystery around getting an MTM crossover right but at the end of the day unless you are trying to reduce the narrowness of the vertical response, if you keep the CTC distance down it should be pretty much like designing another non MTM crossover.
But this is a bit of a digression as you are looking for an existing design...
Tony.
Still waiting for me to get off my butt and order parts to complete my active crossovers so I can run them with my MTM's There are a lot of "rules" with MTM's but they are generally if you want the original D'appolito style. I just made sure my mids were as close to the tweeter as I could get (helped by my driver combo being time aligned without much trickery) and went with a 4th order accoustic slope, in my case at 2.8Khz.
Theres a lot of mystery around getting an MTM crossover right but at the end of the day unless you are trying to reduce the narrowness of the vertical response, if you keep the CTC distance down it should be pretty much like designing another non MTM crossover.
But this is a bit of a digression as you are looking for an existing design...
Tony.
Thanks for the above info
The marshall leach crossover is pretty simple, and as mentioned I could add another bass driver. I think in this case, running them in parallel to maximise amp power and then halving the lowpass inductor as well as dropping a few db off the l-pad to bring the tweeter up a bit to suit(maybe ditching the L-pad all together as it is only 3db) I could prototype a crossover and try it on one of my existing JV60 speakers as it's already in the 'shape' of a d'appolito.
Hopefully that should give good sensitivity and it looks as though there's no real BSC in the design which suits me perfectly(the crossover relies on the natural P17 rolloff). Worth a try for the small outlay for one x-over at least
I have searched for the John K crossover for ages! Thanks for posting that up too I believe it's a much lower x-over point which may work as an MTM a little better due to driver spacing etc. Although it looks a little harder to get the level of the tweeter to be right as it's not a 'simple' l-pad.
@wintermute I have done a few sims of the M26 and it seems fairly good for most applications as long as you don't mind a largish box. Was considering building 4 reflex boxes and moving them around the theatre as required for optimum bass coverage. I have total freedom of placement behind the front screen as they are hidden(can even mount it up high if I wanted) or multiples in stacks etc. I will probably have at least one in the back corner/alcove. The Dayton I have is a monster and can make the room 'shudder' no problem but as it's one driver, there are certainly nulls around the room. Had even considered the 4 10's for 'upper' sub duty(40-80hz) and the Dayton below 40(it goes well below 20hz sealed)
The marshall leach crossover is pretty simple, and as mentioned I could add another bass driver. I think in this case, running them in parallel to maximise amp power and then halving the lowpass inductor as well as dropping a few db off the l-pad to bring the tweeter up a bit to suit(maybe ditching the L-pad all together as it is only 3db) I could prototype a crossover and try it on one of my existing JV60 speakers as it's already in the 'shape' of a d'appolito.
Hopefully that should give good sensitivity and it looks as though there's no real BSC in the design which suits me perfectly(the crossover relies on the natural P17 rolloff). Worth a try for the small outlay for one x-over at least
I have searched for the John K crossover for ages! Thanks for posting that up too
I believe it's a much lower x-over point which may work as an MTM a little better due to driver spacing etc. Although it looks a little harder to get the level of the tweeter to be right as it's not a 'simple' l-pad.@wintermute I have done a few sims of the M26 and it seems fairly good for most applications as long as you don't mind a largish box. Was considering building 4 reflex boxes and moving them around the theatre as required for optimum bass coverage. I have total freedom of placement behind the front screen as they are hidden(can even mount it up high if I wanted) or multiples in stacks etc. I will probably have at least one in the back corner/alcove. The Dayton I have is a monster and can make the room 'shudder' no problem but as it's one driver, there are certainly nulls around the room. Had even considered the 4 10's for 'upper' sub duty(40-80hz) and the Dayton below 40(it goes well below 20hz sealed)
I'll probably downsize mine a little when I get around to making new cabinets. The plan for mine is strictly stereo (acting as stands for the MTM's) and crossing to the MTM's as high as 300Hz. The current boxes (which are very poor) are 70L tuned I think to 30Hz. I'll probably go for somewhere between 50 and 60L tuned a bit higher. If space (and WAF) wasn't an issue I might have gone for something closer to 90L.
Using between 40 and 80 Hz with the Dayton below 40 sounds like a decent option, you could probably push the M26s down to 30Hz, or alternatively make them in smaller boxes only having to do 40Hz and you will get better transient response and a rolloff that will intergrate well with the dayton.... 55L and 33Hz tuning might not be bad for that application!
Tony.
Using between 40 and 80 Hz with the Dayton below 40 sounds like a decent option, you could probably push the M26s down to 30Hz, or alternatively make them in smaller boxes only having to do 40Hz and you will get better transient response and a rolloff that will intergrate well with the dayton.... 55L and 33Hz tuning might not be bad for that application!
Tony.
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I have the Ultimax 15. Its an extremely nice driver and currently sits in just over 5 cubes sealed. I have it built in a tall and shallow enclosure behind the screen which is placed about 2/3 along the wall. Its not too bad there for low stuff but 60hz or so theres noticable holes. It could stay where it is if I integrated other subs and split bass freqencies
I have no complaints about sound or extension at all. Sometimes you feel movement but can't hear a thing! I have a big alcove in the back which would make a perfect spot for a huge LLT enclosure
With a bit of simming, 50L and 38hz actually gives more output and better excursion control if used with a 24db/oct linkwitz riley network(active obviously) Tuning lower reduces output between 40 and 50hz while adding a few mm of excursion(drops power handling to below 100 watts each). At 50l 38hz you can run more or less rated 160wrms constantly and more on 'program' material as the vifa has a short term rating of 500w for peaks. I don't think there's much to gain from trying to get to 30hz with the m26's unless I want big boxes/low power handling.
The Dayton in 10cuft tuned to 16hz as a monster low frequency box will not reach xmax with 500wrms until 15hz or lower which is pretty good and they are known for taking a bit more before distortion really sets in. -10db WITHOUT room gain is 11hz (-3 is 16hz)with a 40hz 24db lowpass which should be enough haha. Does 110db at 20hz at 500w! It's a super clean driver so combined with 4 m26's for upper bass should be a nice system!
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