I have built a pair of Singular cabinets with 18mm MDF, I heard a friend's singulars with AER Mk1 drivers and was instantly hooked.
I just HAD to have some but could not afford the superb (and incredibly efficient) AER drivers.
I wish to tinker and tweak to see how good I can get these relatively cheap drivers to perform.
I still haven't painted/finished the cabinets yet.
The back chambers are stuffed with a shredded polyester pillow from our guest room (the shops were closed, ok?)
Layers from the other guest room pillow were carefully peeled off and trimmed to make a 3cm thick layer to fit in the bottom of the U bend.
So here is a thread to share my experiences and for people to contribute ideas. Hopefully people can learn from my experiences.
So far I have added some blu-tac secured with wool to try to damp the frame/magnet connection. (see picture)
There are various comments here and there I've made on related strings, I'll attempt to distill them here.
So far I installed the drivers to the cabinets about 4 days ago and gave them an 8 hour run at "watching TV" volume, a couple of CDs at "I'm listening to music" volume and a fair thrashing for half a Metallica CD at "let's see what they can take" volume this afternoon, (until my better half had a headache from it).
They are certainly sounding a lot better than when I first listened to them. (or I'm getting used to them) I have dropped the applied signal volume by about 12-14 dB since I started to maintain a normal listneing volume. my old Speakers are Tannoy M15 at 85 dB/w/m. These are a 2 way 8 inch bass reflex speaker. The worst sounding of the new and old speakers will be used for the rear surround channels.
Pit Hinder had some comments I cut and paste here and add my comments in <like this>:
Tweaking the drivers...YES! But taking a knife to them to add a phase plug amounts to open heart surgery. Try reversible measures first, you'll be astonished by what affordable drivers can do. <OzMikeH: if it helps a little bit I am not afraid to do it>
#1 The .98c trick. (Thanks GM for reminding us). Wrap a thread of wool around the whizzer, down where it meets the main cone. <I will try this, what size? thick and fluffy? what about a pipecleaner or too heavy?>
#2 Felt, or as innerconflict, the Nonphony from Caliphony, has proven to be good, simple household sponge. Use double sided adhesive tape to fix it to the inside of the basket legs. <I do not trust the double sided adhesive, I will try this tied on with string with some silicone sealant underneath>
#3 Caulking on the outside of the basket legs and (very effective) on the front of the magnet and in the gap between magnet and basket. <I have applied blu-tac so far, I was nervous about irreversible changes at first and blu tac can be removed, then I disassemble to finish/paint I will use caulk>
I just HAD to have some but could not afford the superb (and incredibly efficient) AER drivers.
I wish to tinker and tweak to see how good I can get these relatively cheap drivers to perform.
I still haven't painted/finished the cabinets yet.
The back chambers are stuffed with a shredded polyester pillow from our guest room (the shops were closed, ok?)
Layers from the other guest room pillow were carefully peeled off and trimmed to make a 3cm thick layer to fit in the bottom of the U bend.
So here is a thread to share my experiences and for people to contribute ideas. Hopefully people can learn from my experiences.
So far I have added some blu-tac secured with wool to try to damp the frame/magnet connection. (see picture)
There are various comments here and there I've made on related strings, I'll attempt to distill them here.
So far I installed the drivers to the cabinets about 4 days ago and gave them an 8 hour run at "watching TV" volume, a couple of CDs at "I'm listening to music" volume and a fair thrashing for half a Metallica CD at "let's see what they can take" volume this afternoon, (until my better half had a headache from it).
They are certainly sounding a lot better than when I first listened to them. (or I'm getting used to them) I have dropped the applied signal volume by about 12-14 dB since I started to maintain a normal listneing volume. my old Speakers are Tannoy M15 at 85 dB/w/m. These are a 2 way 8 inch bass reflex speaker. The worst sounding of the new and old speakers will be used for the rear surround channels.
Pit Hinder had some comments I cut and paste here and add my comments in <like this>:
Tweaking the drivers...YES! But taking a knife to them to add a phase plug amounts to open heart surgery. Try reversible measures first, you'll be astonished by what affordable drivers can do. <OzMikeH: if it helps a little bit I am not afraid to do it>
#1 The .98c trick. (Thanks GM for reminding us). Wrap a thread of wool around the whizzer, down where it meets the main cone. <I will try this, what size? thick and fluffy? what about a pipecleaner or too heavy?>
#2 Felt, or as innerconflict, the Nonphony from Caliphony, has proven to be good, simple household sponge. Use double sided adhesive tape to fix it to the inside of the basket legs. <I do not trust the double sided adhesive, I will try this tied on with string with some silicone sealant underneath>
#3 Caulking on the outside of the basket legs and (very effective) on the front of the magnet and in the gap between magnet and basket. <I have applied blu-tac so far, I was nervous about irreversible changes at first and blu tac can be removed, then I disassemble to finish/paint I will use caulk>
Attachments
I've given them a good listen and decided I need a super tweeter. The high end isnt there in the flesh and not on the datasheet for the driver either.
I'm thinking of a shaped high pass filter on the tweeter starting at about 12-13kHz where the Fe207E starts rolling off.
I want fair off axis (30 degrees) response and nice flat freq response from 10k right through to 20k.
I've only looked at fostex driver so far.
They need to be same or beter efficiency than the main speakers, (95dB/w/m) which rules out the fostex ribbon tweeter, this also has a weird looking off axis performance.
It's come down to the T90A (a little cylinder thing) or a FT96H (panel mount) spec sheets here:
http://www.fostexinternational.com/docs/speaker_comp/Horn-Tweeters.shtml
The cheaper FT96H actually looks better performance-wise other than the slightly lumpy response.
Has anyone used either of these?
Doesn anyone have any other recommendations?
I'm thinking of a shaped high pass filter on the tweeter starting at about 12-13kHz where the Fe207E starts rolling off.
I want fair off axis (30 degrees) response and nice flat freq response from 10k right through to 20k.
I've only looked at fostex driver so far.
They need to be same or beter efficiency than the main speakers, (95dB/w/m) which rules out the fostex ribbon tweeter, this also has a weird looking off axis performance.
It's come down to the T90A (a little cylinder thing) or a FT96H (panel mount) spec sheets here:
http://www.fostexinternational.com/docs/speaker_comp/Horn-Tweeters.shtml
The cheaper FT96H actually looks better performance-wise other than the slightly lumpy response.
Has anyone used either of these?
Doesn anyone have any other recommendations?
I have a FE167E and thinking of adding a tweeter to it, the dispersion or off axis performance is not very good above 6-8khz, by adding a good tweeter would improve situation greatly. the same with FE207E.
go and do a serach on this forum on "adding a tweeter to full range" you will find an extensive discussion".
go and do a serach on this forum on "adding a tweeter to full range" you will find an extensive discussion".
thanks Ttan98.
Having read the thread..
1: wide dispersion on a helper tweeter for a fullrange is not necessarily a good thing. I should look for similar dispersion of the FR driver and tweeter within the crossover freq. range. Since I am fitting phase plugs to widen the HF on my FE207E the factory information is useless to me. I'll just have to estimate what will match and see how it sounds.
2: Ribbon tweeters can be integrated but only with great care. It is easy to get it wrong.
3: I might not want a tweeter after I fit the phase plugs.
4: Filtering the extreme highs and lows off the fullrange driver can help it's mid-range performance.
5: Time coherence is critical for good imaging. I need to figure out what phase offset the high pass capacitor for the tweeter will cause and whether it will be audible. Physical position of the tweeter is minor compared to the effect of the filter components. I need to do some more reading on the phase effect of crossover parts.
I may need to consider some fudge on the Fullrange driver to give it the same phase offset as the tweeter.
My main aims are good imaging and extended response.
Having read the thread..
1: wide dispersion on a helper tweeter for a fullrange is not necessarily a good thing. I should look for similar dispersion of the FR driver and tweeter within the crossover freq. range. Since I am fitting phase plugs to widen the HF on my FE207E the factory information is useless to me. I'll just have to estimate what will match and see how it sounds.
2: Ribbon tweeters can be integrated but only with great care. It is easy to get it wrong.
3: I might not want a tweeter after I fit the phase plugs.
4: Filtering the extreme highs and lows off the fullrange driver can help it's mid-range performance.
5: Time coherence is critical for good imaging. I need to figure out what phase offset the high pass capacitor for the tweeter will cause and whether it will be audible. Physical position of the tweeter is minor compared to the effect of the filter components. I need to do some more reading on the phase effect of crossover parts.
I may need to consider some fudge on the Fullrange driver to give it the same phase offset as the tweeter.
My main aims are good imaging and extended response.
OzMikeH said:
Take the plunge and put in the phase plugs. You will not regret it. It is easy to do with a steady hand and a sharp exacto knife. After you cut it close with the exacto grab some 180 grit sand paper and smooth it down to a finished edge. Also, make sure you have one of those battery operated keyboard vacuums handy to suck out any debris. It's not that hard.
Phase plugs are in the mail...
Thanks for the tip with the sandpaper.
I'll also put a brick under the back of the cabinet while I am doing it, then run them for a while that way to shake any bits out.
Planet10 has suggested the much cheaper Fostex FT17. this is a third and a quarter of the price of the other two tweeters I was considering.
thomaseliot is using this combination, Last I heard with a single 1uF capacitor.
http://www.diyaudio.com/forums/showthread.php?postid=1056970#post1056970
The power handling of the FT17 is only "30W music power" so I might end up blowing it up anyway. Especially with a simple crossover, the LF will be too much for it.
Planet10 said:
"I actually have FT17s i'm planning on using with with my 207s --- i'm going to start out at 7-8k 1st order series XO -- maybe 2nd order on the tweeter. Experiments i did awhile back with tweeters XOed quite high is that you can get away with a lot."
Thanks for the tip with the sandpaper.
I'll also put a brick under the back of the cabinet while I am doing it, then run them for a while that way to shake any bits out.
Planet10 has suggested the much cheaper Fostex FT17. this is a third and a quarter of the price of the other two tweeters I was considering.
thomaseliot is using this combination, Last I heard with a single 1uF capacitor.
http://www.diyaudio.com/forums/showthread.php?postid=1056970#post1056970
The power handling of the FT17 is only "30W music power" so I might end up blowing it up anyway. Especially with a simple crossover, the LF will be too much for it.
Planet10 said:
"I actually have FT17s i'm planning on using with with my 207s --- i'm going to start out at 7-8k 1st order series XO -- maybe 2nd order on the tweeter. Experiments i did awhile back with tweeters XOed quite high is that you can get away with a lot."
OzMikeH said:
I'm using FE206Es and their top end might be a little hotter. I would hold off on the tweeters until I give the phase plugs a good listen. I also toe in my speakers slightly and that may make a difference. There is a suggested setup on the FE207E datasheet for running the 207 with the FT17H utilizing a cap anf a t-pad. Just be aware that it will reduce your impedance to 4 ohms if you use the tweeter.
I think I'll need the tweeter anyway.
the FE207E runs out of puff at about 12kHz, from what i understand phase plugs will help disperse what's already there better, they will not extend frequency response by 8kHz.
I need that top end filled up, otherwise I may as well be listening to cassettes.
So I will be installing a tweeter, the only questions are where, what type and at what crossover frequency.
The frequency can only be determined after I install the phase plugs.
I want to put it underneath the main driver, it is closer to ear height for my seating and has a much higher WAF than something sticking out the top.
Please let me know if this is a horribly wrong thing to do.
I Am skinning over the MDF with some thin plywood, I can then run a quarter round router bit along all edges to take it down to leave a thin line of MDF then stain it all a dark cherry. I was trying to figure out how to hide the edges then I thought I should just make them a feature.
the FE207E runs out of puff at about 12kHz, from what i understand phase plugs will help disperse what's already there better, they will not extend frequency response by 8kHz.
I need that top end filled up, otherwise I may as well be listening to cassettes.
So I will be installing a tweeter, the only questions are where, what type and at what crossover frequency.
The frequency can only be determined after I install the phase plugs.
I want to put it underneath the main driver, it is closer to ear height for my seating and has a much higher WAF than something sticking out the top.
Please let me know if this is a horribly wrong thing to do.
I Am skinning over the MDF with some thin plywood, I can then run a quarter round router bit along all edges to take it down to leave a thin line of MDF then stain it all a dark cherry. I was trying to figure out how to hide the edges then I thought I should just make them a feature.
OzMikeH said:I think I'll need the tweeter anyway.
the FE207E runs out of puff at about 12kHz, from what i understand phase plugs will help disperse what's already there better, they will not extend frequency response by 8kHz.
I need that top end filled up, otherwise I may as well be listening to cassettes.
So I will be installing a tweeter, the only questions are where, what type and at what crossover frequency.
The frequency can only be determined after I install the phase plugs.
I want to put it underneath the main driver, it is closer to ear height for my seating and has a much higher WAF than something sticking out the top.
Please let me know if this is a horribly wrong thing to do.
I Am skinning over the MDF with some thin plywood, I can then run a quarter round router bit along all edges to take it down to leave a thin line of MDF then stain it all a dark cherry. I was trying to figure out how to hide the edges then I thought I should just make them a feature.
You obviously are free to do what you choose but the FE207E does not "run out of puff" at 12K. Check the spec sheet and ask some people who own them. They are essentially a shielded version of the FE206E with a little higher QTS. I have not found my FE206Es to fall off in the highs at 12KHz and I seriously doubt that Fostex would be selling many of them if they did since they state that the frequency response is "Fo to 20KHz". Just an opinion but you may want to listen to them by themselves in a suitable enclosure before you start diddling with crossover points and tweeters. Just a suggestion.
OzMikeH said:
Maybe there is more difference between the 206 and the 207 than I thought. The only one that has to like your speakers is you. I was only hoping to save you some time and money. I would still do the phase plugs. Let us know how it turns out. BTW are you using a SS or tube amp to drive them?
I was hoping to save me some money too.
I am away from home at the moment and my Phase plugs are there waiting for me.
I am using a SS amp. A Harman Kardon AV receiver,
50W when used in 2 channel mode.
Allegedly good to 100kHz, with high current capability, not that it matters with such a benign load as a single driver. The speakers are always the worst part of any reasonable system so I started with them.
On a listening test on my friend's singulars with AER drivers I was very surprised I could still hear right up to 20kHz, I am a radio communications technician, so I often tune radio receiver front ends by ear. I have listened to a very nice tube amp that could be run in triode and pentode mode with variable negative feedback. I liked it better with lots of negative feedback in pentode mode. So If I build an Amp it will probably be a low noise SS one. My sensitivity to high frequencies has me wary of T amps, I turn the television off once I have started the PSX cd player because the 16kHz noise is distracting.
I must say that I am peased with the bass and midrange, it's just the high end that needs something. AER Mk1 drivers would be the technically better fix but they will cost 10 time the price of the Fostex ones. They are very nearly worth the price to me.
My current thinking is to build a 12dB/octave Linkwitz riley style crossover at 10kHz using metallized polypropylene capacitors. I have just ordered some Fostex FT17H. I wanted the steeper crossover to attempt to reduce nulls from both drivers producing the same frequency, I'll tame the 98.5dB /w tweeter down by 3dB with a resistor network arranged to maintain the 8 ohm impedance. I haven't ordered the crossover components yet, I will see what changes with the phase plugs. I can play with this easily, the crossovers will be extrnal, Fortunately I used 4 core cable and neutrik connectors.
I was going to put inside the basket with some 1/4 inch thick foam triangles near the centre, something as wide as the basket "spoke" tapering to a point about 2/3 of the way out from the centre. Will this help or will it increase the effective mass of the cone? (I am sticking it to the basket, not the cone) With an Xmax of 1.5mm i should be safe.
I want to glue some wooden wedges on the back of the basket "arms" back to the magnet cover to really stiffen it up and reduce turbulence over the sharp edge. I'll take pictures.
I am away from home at the moment and my Phase plugs are there waiting for me.
I am using a SS amp. A Harman Kardon AV receiver,
50W when used in 2 channel mode.
Allegedly good to 100kHz, with high current capability, not that it matters with such a benign load as a single driver. The speakers are always the worst part of any reasonable system so I started with them.
On a listening test on my friend's singulars with AER drivers I was very surprised I could still hear right up to 20kHz, I am a radio communications technician, so I often tune radio receiver front ends by ear. I have listened to a very nice tube amp that could be run in triode and pentode mode with variable negative feedback. I liked it better with lots of negative feedback in pentode mode. So If I build an Amp it will probably be a low noise SS one. My sensitivity to high frequencies has me wary of T amps, I turn the television off once I have started the PSX cd player because the 16kHz noise is distracting.
I must say that I am peased with the bass and midrange, it's just the high end that needs something. AER Mk1 drivers would be the technically better fix but they will cost 10 time the price of the Fostex ones. They are very nearly worth the price to me.
My current thinking is to build a 12dB/octave Linkwitz riley style crossover at 10kHz using metallized polypropylene capacitors. I have just ordered some Fostex FT17H. I wanted the steeper crossover to attempt to reduce nulls from both drivers producing the same frequency, I'll tame the 98.5dB /w tweeter down by 3dB with a resistor network arranged to maintain the 8 ohm impedance. I haven't ordered the crossover components yet, I will see what changes with the phase plugs. I can play with this easily, the crossovers will be extrnal, Fortunately I used 4 core cable and neutrik connectors.
I was going to put inside the basket with some 1/4 inch thick foam triangles near the centre, something as wide as the basket "spoke" tapering to a point about 2/3 of the way out from the centre. Will this help or will it increase the effective mass of the cone? (I am sticking it to the basket, not the cone) With an Xmax of 1.5mm i should be safe.
I want to glue some wooden wedges on the back of the basket "arms" back to the magnet cover to really stiffen it up and reduce turbulence over the sharp edge. I'll take pictures.
Interesting damping material
I have stumbled across some very dense damping material, the only problem is keeping it in place during loud passages.
It moves around so much I am worried about damage to the rear of the driver.
Any suggestions?
But seriously now, I think I need to make something to keep him out, any serious suggestions?
I have stumbled across some very dense damping material, the only problem is keeping it in place during loud passages.
It moves around so much I am worried about damage to the rear of the driver.
Any suggestions?
But seriously now, I think I need to make something to keep him out, any serious suggestions?
Attachments
A fair question -having a cat enter your speaker cabinet could get expensive, and also damage the cat if it happens to be sleeping in there & you fire up Bruce Dickinson's latest solo album.
I'd try a stiff wire grill across the opening. It shouldn't ring significantly, and a touch of that is a sight better than a pair of ruined drivers or a deafened cat.
I'd try a stiff wire grill across the opening. It shouldn't ring significantly, and a touch of that is a sight better than a pair of ruined drivers or a deafened cat.
Guesstimating FE207E acoustic centre at 10kHz
How would I go about estimating the acoustic centre of the FE207E at 10kHz?
I'm guessing it might be something to do with a plane through the whizzer where it's diameter is a certain portion of a wavelength of 10k?
While I'm at it I need to do the same for the FT17H.
My test equipment consists of a PC for test tones and easily fooled ears. I can borrow a sound level meter (with A or C weighting scales) but it is a real hassle to get it.
The cabinets will be clad with ply, so I can chose the ply thickness to match my required offset between the two drivers.
Is it a horrible thing to mount the tweeters under the fullrangers? It's closest to ear height on these cabinets. I am also considering mounting them slightly off centre toward the outside - this appears to reduce the edge diffraction effects because the edges are now different distances. This leads me to believe there is an optimum offset distance so the edges null each other too.
I've bitten the bullet and ordered the crossover components and an inductance meter. I'll unwind some pre-made inductors until I get the right value. I may as well soak them afterward in some cheap varnish too.
For the 10k frequency the capacitances work out at 1uF and 0.5uF so I have ordered eight 1uf metallised polypropylene caps. I can match a pair and a double pair and use the last two for the playstation DAC output.
Oh yeah, Planet10's phase plugs helped a lot, My wife thinks "they look much better than the beady little eyes did" too. the speakers are a lot more listenable and seen more "even" in the high end. I have no idea why Fostex doesn't do this in the first place, it wouldn't cost much more for a plastic bullet instead of that little mesh stuck in the dust cap.
A tip when cutting the dust caps out on the Fostex 206 and 207. cut around the little mesh in a circle, approx 9/16 of an inch diameter. Cutting through the mesh results in lots of little bits of the mesh going everywhere.
How would I go about estimating the acoustic centre of the FE207E at 10kHz?
I'm guessing it might be something to do with a plane through the whizzer where it's diameter is a certain portion of a wavelength of 10k?
While I'm at it I need to do the same for the FT17H.
My test equipment consists of a PC for test tones and easily fooled ears. I can borrow a sound level meter (with A or C weighting scales) but it is a real hassle to get it.
The cabinets will be clad with ply, so I can chose the ply thickness to match my required offset between the two drivers.
Is it a horrible thing to mount the tweeters under the fullrangers? It's closest to ear height on these cabinets. I am also considering mounting them slightly off centre toward the outside - this appears to reduce the edge diffraction effects because the edges are now different distances. This leads me to believe there is an optimum offset distance so the edges null each other too.
I've bitten the bullet and ordered the crossover components and an inductance meter. I'll unwind some pre-made inductors until I get the right value. I may as well soak them afterward in some cheap varnish too.
For the 10k frequency the capacitances work out at 1uF and 0.5uF so I have ordered eight 1uf metallised polypropylene caps. I can match a pair and a double pair and use the last two for the playstation DAC output.
Oh yeah, Planet10's phase plugs helped a lot, My wife thinks "they look much better than the beady little eyes did" too. the speakers are a lot more listenable and seen more "even" in the high end. I have no idea why Fostex doesn't do this in the first place, it wouldn't cost much more for a plastic bullet instead of that little mesh stuck in the dust cap.
A tip when cutting the dust caps out on the Fostex 206 and 207. cut around the little mesh in a circle, approx 9/16 of an inch diameter. Cutting through the mesh results in lots of little bits of the mesh going everywhere.
Time alignment idea went out the window after reading the "Time alignement fundamentals" thread. (search for that exact spelling if anyone wants to read it.) I like the idea in that thread of notching out the edge of the tweeter mounting flange to get it closer to the centre of the woofer. That thread was very interesting reading until the little tiff broke out.
The whole time alignment tangent came about because of the potential "suckout" issues from getting the phase out of whack due to the high pass filter for the tweeter. I'm learning new things all of the time with this project, it's great.
Tweeter position is the current thing rolling around in my head, I only get one chance to get this right, I can play all I like with the external crossovers later on.
Upward firing tweeter sounds interesting, probably sounds good all around the room but with vague imaging?
there is a relatively cheap fostex ring radiator tweeter with a remarkably broad radiation pattern which I may try in future. The Ft17 ones are dirt cheap so I don't mind demoting them to filling-the-hole-in-the-cabinet status later on.
The whole time alignment tangent came about because of the potential "suckout" issues from getting the phase out of whack due to the high pass filter for the tweeter. I'm learning new things all of the time with this project, it's great.
Tweeter position is the current thing rolling around in my head, I only get one chance to get this right, I can play all I like with the external crossovers later on.
Upward firing tweeter sounds interesting, probably sounds good all around the room but with vague imaging?
there is a relatively cheap fostex ring radiator tweeter with a remarkably broad radiation pattern which I may try in future. The Ft17 ones are dirt cheap so I don't mind demoting them to filling-the-hole-in-the-cabinet status later on.
Ok Guys, be Honest, Would I be better off with a Bruce?
I have been skimming through the Frugal horn offspring thread and saw this passing comment from Dave (Planet10) in response to offsetting the driver.
"I don't think enuff to worry about... that's what we plan for our 207/FT17 Bruce...."
It just happens that I have a 207 and FT17.
These boxes only owe me about 2 cartons of beer worth of materials anyway. Still useful as cat house. What are your thoughts Scottmoose? Reading your comments elsewhere you seem to be one of the boffins on these drivers. I know it'll be harder for the damn cat to get inside the Bruce anyway.
I have been skimming through the Frugal horn offspring thread and saw this passing comment from Dave (Planet10) in response to offsetting the driver.
"I don't think enuff to worry about... that's what we plan for our 207/FT17 Bruce...."
It just happens that I have a 207 and FT17.
These boxes only owe me about 2 cartons of beer worth of materials anyway. Still useful as cat house. What are your thoughts Scottmoose? Reading your comments elsewhere you seem to be one of the boffins on these drivers. I know it'll be harder for the damn cat to get inside the Bruce anyway.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.