Yes, that's true. The P13WH is useless in the bass section. It is also difficult to be used as a midrange in 3-way system. But Transmission Line is still possible. I like PL14 (not as sweet as P13 but best overall). I think it was my favorite Vifa driver. Small but can sound as big as 10" driver.
There is Linkwitz Transform circuit. The IC-based circuit might be an issue, but for a "cheap" system, where "good" bass is expected from small driver, the bass sound will never sound natural anyway so I think active crossover will have less cons and more pros.
The active circuit allows for small enclosure. And for nearfield listening, cheap small power IC amplifiers can be used. I like TDA2009 because it's quality spread is small as compared to other ICs from TDA and LM. With other ICs you need more "luck" to get a good quality one (at least fall in "typical" performance criteria).
How about the gurus get together and write: "The Idiots Guide to DIY Loudspeakers."
For example:
The drivers used in the Audax HT kit are on sale at PE. For a 2-way:
AP170Z0 - $22.04
TM025F1 - $11.04
With x-over parts, you should be able to come in around $100.
Just my 0.02-newbie-cents about the subject.
+1 great alternatives to the vifa seas drivers quoted. i actually built the audax HT centre channel minus AP200ZO and HP bits of crossover, and the AP130ZO plus TW025F1 make a pretty good introduction to real hifi, at a good price. I still have mine, and im still surprised by just how good they can sound. Ideal for a 1st build.
Apologies, late to the party AGAIN! pity were using the same ol recycled drivers in another vifa bookshelf...they arent nearly as cheap and easily sourced outside NA. Nevermind
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I have been very satisfied with my Vifa combo and recently went bipole (one set front - one set rear) in a metronome. I would like to try the series crossover but am unsure what needs to be changed. The simple but costly solution would be to treat each pair discretely and parallel the pair.
Can someone tel me how to change the values contained in post #179 by rabbitz for a 4 ohm pair?
Can someone tel me how to change the values contained in post #179 by rabbitz for a 4 ohm pair?
The best starting xo for a bipolar is the last one from post #179 as it doesn't have BSC.
Changing the inductor and cap values as suggested would in theory be a starting point but the value of R has an effect on both the tweeter and woofer unlike a parallel xo. You could try it but I wouldn't be confident as I can't model it or have never tried it but if you like playing with designs, then play away. Start without R and add R starting at 1R (then increase) to each tweeter as required but this could be a long process.
The safest would be using a separate xo for each tweeter/woofer and then parallel but there is no guarantee of the sound as the xo was designed and tweaked for a monopole only. The impedance would drop as low as 3R5 (so would the above) which could be a problem for some amps. I've added the impedance graph for a single as designed xo for reference.
There is an existing bipolar design, the TLb, using only 1 cap in the xo.
The TLb -- Introduction
Changing the inductor and cap values as suggested would in theory be a starting point but the value of R has an effect on both the tweeter and woofer unlike a parallel xo. You could try it but I wouldn't be confident as I can't model it or have never tried it but if you like playing with designs, then play away. Start without R and add R starting at 1R (then increase) to each tweeter as required but this could be a long process.
The safest would be using a separate xo for each tweeter/woofer and then parallel but there is no guarantee of the sound as the xo was designed and tweaked for a monopole only. The impedance would drop as low as 3R5 (so would the above) which could be a problem for some amps. I've added the impedance graph for a single as designed xo for reference.
There is an existing bipolar design, the TLb, using only 1 cap in the xo.
The TLb -- Introduction
Attachments
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Thanks to both of you.
I had built and used the Tlb way back and thoroughly enjoyed it. In terms of sound stage and overall smoothness surprisingly I think it is better than the Metronome but WAF intruded!
I have continued to used the capacitor option only but hoped that there was something better.
Your replies have given me a starting point.
rabbitz, perhaps I could ask you to comment on which set up would be preferred if using a single set up on an OB?
I had built and used the Tlb way back and thoroughly enjoyed it. In terms of sound stage and overall smoothness surprisingly I think it is better than the Metronome but WAF intruded!
I have continued to used the capacitor option only but hoped that there was something better.
Your replies have given me a starting point.
rabbitz, perhaps I could ask you to comment on which set up would be preferred if using a single set up on an OB?
Hi bjohng
None would work on an OB due to the roll off below Fe and slope up to Fp. You would end up with no bass and a large loss in the mids. OBs really need very wide baffles and a 3-way design with a large woofer in a vented or sealed design even though OB woofers can work but are generally specialised large drivers. These require a lot of crossover work as have to allow for for the behaviour to Fe, upward slope to Fp and increase above Fp in addition to driver behaviour.
To understand a bit on OB, look at this page and it's design links as gives you an idea of losses and slopes when using OB. Do some calcs with your baffle width and you'll see what I mean.
The Subwoofer DIY Page v1.1 - Dipole Bass Systems
This is the type of behaviour and ignore the frequency as that's baffle width dependant.
None would work on an OB due to the roll off below Fe and slope up to Fp. You would end up with no bass and a large loss in the mids. OBs really need very wide baffles and a 3-way design with a large woofer in a vented or sealed design even though OB woofers can work but are generally specialised large drivers. These require a lot of crossover work as have to allow for for the behaviour to Fe, upward slope to Fp and increase above Fp in addition to driver behaviour.
To understand a bit on OB, look at this page and it's design links as gives you an idea of losses and slopes when using OB. Do some calcs with your baffle width and you'll see what I mean.
The Subwoofer DIY Page v1.1 - Dipole Bass Systems
This is the type of behaviour and ignore the frequency as that's baffle width dependant.
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This quote comes from a little while back. I have to agree that this thread is VERY hairy.
Seems like somewhere in here is exactly what I'm hoping to find, but I'm having a rough time finding it.
Has something become of this idea?
It is a bit discouraging that from what I read a lot of talk went to the vifa p13Wh-00-08 and what? It's gone now?
I'm glad I skipped ahead about 300 messages.
This site is no doubt very useful, but some of the threads get so long it is completely overwhelming.
Search doesn't solve everything and when the answer is buried at message 500/4500 that started in 2006 and so many products seem to go out of production.
I'm guilty here---talk about off thread...
I'm glad I skipped ahead about 300 messages.
This site is no doubt very useful, but some of the threads get so long it is completely overwhelming.
Search doesn't solve everything and when the answer is buried at message 500/4500 that started in 2006 and so many products seem to go out of production.
I'm guilty here---talk about off thread...
Rumours of the death of the P-13?/
It does seem to avoid a complete death how-ever. There was some debate over the consistency of quality control and there does seem to be the belief that Chinese drivers are quite bad.
As a starter project this one had great benefits, it sounded really good in all the iterations I heard ( mine was just a cap on the D-27-45-06 tweeter) but my box never got finished as I used mine as the basis for our bedroom 2.5 way.
John the thread itself may me moribund but the melody still remains.
Just start an email cascade aimed at Scanspeak ( at least I think it is now made under the Scanspeak label )to get the price of the new P-13 down to a reasonable level and tell us what the new model number of the D-27-45-06 tweeter is and you can start again.
It does seem to avoid a complete death how-ever. There was some debate over the consistency of quality control and there does seem to be the belief that Chinese drivers are quite bad.
As a starter project this one had great benefits, it sounded really good in all the iterations I heard ( mine was just a cap on the D-27-45-06 tweeter) but my box never got finished as I used mine as the basis for our bedroom 2.5 way.
John the thread itself may me moribund but the melody still remains.
Just start an email cascade aimed at Scanspeak ( at least I think it is now made under the Scanspeak label )to get the price of the new P-13 down to a reasonable level and tell us what the new model number of the D-27-45-06 tweeter is and you can start again.
Looks to me like partsexpress has something called a
D27TG-35-06 Vifa D27TG-35-06 1" Silk Dome Tweeter 264-1022
Is that the same animal?
I really like the look of that esquire design from S. Blaier in 96.
Any advice on the substitute for the P13 in the esquire project?
D27TG-35-06 Vifa D27TG-35-06 1" Silk Dome Tweeter 264-1022
Is that the same animal?
I really like the look of that esquire design from S. Blaier in 96.
Any advice on the substitute for the P13 in the esquire project?
This thread started over 8 years ago and the drivers used were old back then. They still can be found as the P13 is available at places such as Madisound and Speakerbits. The closest tweeter is the Scan Speak D2606-922000 which is the Vifa D27TG-35-06 that I used in my early version of the design. I have no idea how close it is to the original Vifa D27TG.
Summary of design: http://www.diyaudio.com/forums/multi-way/25590-diyaudio-reference-speaker-project-18.html#post2796418
Summary of design: http://www.diyaudio.com/forums/multi-way/25590-diyaudio-reference-speaker-project-18.html#post2796418
I've been building speakers as a hobbyist since the mid 1960's. My experience assisting Engineers in video at Tektronix and in the surround sound engineering group at Dolby Labs has given me some good insights. I've tried many different designs over the years. I recently designed and built a great tri-amped open baffle system. I've presented it on my hobby website:
http colin //www.spiritone.com/~rob_369
(I hope they don't filter this out)
with more detail than you wanted. Right now I'm building a stereo soundbar with the Polk style hologram effect to go under my 42 inch HD TV. Two 6.5 inch 830875 Peerless drivers (Nomex cone - vented spider) will be electronically forced to be flat to 30HZ (yes, I'm pushing my luck with that but low bass is to die for). The 4th order Linkwitz-Riley active crossover will switch at 110HZ to the array of Peerless (or were they Vifa) (I think the two companies may have combined) TG9FD-10-08 glass fiber cone 3 inch drivers (vented spider and pole piece) across the front (the drivers Roger Russel likes and uses in his latest line array system), and three Dayton ND20FB-4 3/4 inch dome tweeters will put the air in the room above 8kHZ (passive one pole x-over at 8kHZ) (Zaph says these tweets are incredibly flat from 4kHZ to about 25kHZ). None of these 3 drivers need any fancy notch filters to tame resonances, and they appear to be excellent designs, at very cheap dollars. $18 per tweeter, $20ish per 3 inch, and $60 per woofer, (available at either Parts Express or Madisound). There are many good drivers out there. Many bad too. Always look at the frequency response and Xmax numbers, and don't necessarily believe them, although they're probably close to accurate in most cases. These drivers are presently my favorites (I did a LOT of research) and would be an excellent choice for any system design.
I'll have this, the open baffle speakers driven with a modified Bob Carver electronic hologram circuit (so double hologram - one done electronically and one done acoustically), two woofer cabinets with 12 inch Peerless XLS woofers (electronically forced to be acoustically flat to 20HZ), and two side speakers up by the ceiling, aimed directly across at each other a few feet in front of the main listening position. I find a half circle of surround to be less fatiguing over time than a full circle of surround. Acoustic material nailed directly into the corners of the room (as shown on my Aurium Waveguide webpage) did an amazing job of killing room ringing.
I say build the best speaker you can. Do as much research as you can stand to do, and have fun with it. Linkwitz shows his active crossover circuits and EQ on his website. I scaled the values to get the crossover frequencies and EQ I wanted (verified with the SPICE circuit analysis program before building).
One of the troubles with passive crossovers is that the impedance of the drivers is rarely the nominal rating (4 or 8 ohm?). It may be 20 ohms at the frequency you want to cross the driver over at. You can be way off with that unless you know how to measure the impedance of the driver at the frequency of interest. When I'm lazy (always), I just stick a few different caps or coils on the driver and see what the calibrated mic tells me (starting with the calculated value based on the nominal rating). Then I can be more sure of what the outcome will be. There's a lot of tricks to the trade, but until you jump in and make your mistakes, you won't be able to learn to build a speaker you will be proud of every time you see or use it.
http colin //www.spiritone.com/~rob_369
(I hope they don't filter this out)
with more detail than you wanted. Right now I'm building a stereo soundbar with the Polk style hologram effect to go under my 42 inch HD TV. Two 6.5 inch 830875 Peerless drivers (Nomex cone - vented spider) will be electronically forced to be flat to 30HZ (yes, I'm pushing my luck with that but low bass is to die for). The 4th order Linkwitz-Riley active crossover will switch at 110HZ to the array of Peerless (or were they Vifa) (I think the two companies may have combined) TG9FD-10-08 glass fiber cone 3 inch drivers (vented spider and pole piece) across the front (the drivers Roger Russel likes and uses in his latest line array system), and three Dayton ND20FB-4 3/4 inch dome tweeters will put the air in the room above 8kHZ (passive one pole x-over at 8kHZ) (Zaph says these tweets are incredibly flat from 4kHZ to about 25kHZ). None of these 3 drivers need any fancy notch filters to tame resonances, and they appear to be excellent designs, at very cheap dollars. $18 per tweeter, $20ish per 3 inch, and $60 per woofer, (available at either Parts Express or Madisound). There are many good drivers out there. Many bad too. Always look at the frequency response and Xmax numbers, and don't necessarily believe them, although they're probably close to accurate in most cases. These drivers are presently my favorites (I did a LOT of research) and would be an excellent choice for any system design.
I'll have this, the open baffle speakers driven with a modified Bob Carver electronic hologram circuit (so double hologram - one done electronically and one done acoustically), two woofer cabinets with 12 inch Peerless XLS woofers (electronically forced to be acoustically flat to 20HZ), and two side speakers up by the ceiling, aimed directly across at each other a few feet in front of the main listening position. I find a half circle of surround to be less fatiguing over time than a full circle of surround. Acoustic material nailed directly into the corners of the room (as shown on my Aurium Waveguide webpage) did an amazing job of killing room ringing.
I say build the best speaker you can. Do as much research as you can stand to do, and have fun with it. Linkwitz shows his active crossover circuits and EQ on his website. I scaled the values to get the crossover frequencies and EQ I wanted (verified with the SPICE circuit analysis program before building).
One of the troubles with passive crossovers is that the impedance of the drivers is rarely the nominal rating (4 or 8 ohm?). It may be 20 ohms at the frequency you want to cross the driver over at. You can be way off with that unless you know how to measure the impedance of the driver at the frequency of interest. When I'm lazy (always), I just stick a few different caps or coils on the driver and see what the calibrated mic tells me (starting with the calculated value based on the nominal rating). Then I can be more sure of what the outcome will be. There's a lot of tricks to the trade, but until you jump in and make your mistakes, you won't be able to learn to build a speaker you will be proud of every time you see or use it.
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