subjectively there was no vast improvement with the old series Eminence B102 with a "phase" rod - I can't remember if the graph below's "before" condition was with the flat dustcap or as pictured with the cap removed. The cavity should be filled - a wood dowel with no taper would probably be ok if not too long past the former
even tho there was a nasty peak, that peak was missed as it added some "life" to my fake druid
Eminence's new B102 doesn't go very high nor does it have the midrange output of the old version - but is useful for some speakers
stock old vs new B102
even tho there was a nasty peak, that peak was missed as it added some "life" to my fake druid
Eminence's new B102 doesn't go very high nor does it have the midrange output of the old version - but is useful for some speakers
stock old vs new B102
An externally hosted image should be here but it was not working when we last tested it.
That's an interesting twist. I am going to try an open tube also. It might be either very bad or very good. It isn't talked about. It seemed to work when still a little clingfilm on the tube ( that's the tube I had to hand ).
My speakers are stupidly simple. They have evolved a bit. This was only to get an idea. The idea works rather nicely. I hoped to have an OB Dynaco A25. The tweeter is mostly a super tweeter. I am now unwilling to go active as this seems to work!!!! A low mass baffle was better. It was impossible to clamp to. I can see a way and might return to it.
The choke is a mains device. It even has a musical note if pushed too hard. The 12 Lta was crossed via 100 uF. Adding 470 uF was a big deal. The baffle 2 x 4 foot in 50/50 ply MDF ( 1/2 inch , 1 inch total ). The Quad seems to cope with the load of 8 R plus 5R7 reactive.
Even in this crude state the speakers give my Magneplanars a run for their money. Dispersion is better !
The bass is a 15 inch replacement speaker for a Chinese plastic box PA device. Rather nicely made with Qts of 1.2. It costs $50 and the 12 LTa > $100 in the UK. I suspect not unlike the Alpha 15 people say will work. The overlap I use between 15 inch and 12 LTa seems about right. Both speakers seem to be made to a similar recipe. The magnets seem almost identical.
Although using much of the EQ a Quad 33 can offer it is workable. The caps come directly off of the Quad output transitors. 3u3 will be tried next to the tweeters. I have some chokes at a friends house. They also need to be tried. I moded the Quad 33 to suit the Denon DL110 pick up ( about 800 uV I think ) , that was much better than hoped for. As the 15 inch is close to the floor I might remove the choke. It is just possible I will win more than I loose. It looks doubtful, who knows.
This might be my next move.
Jane Asher Wooden Rolling Pin - Preparation Equipment - Jane Asher's Kitchen
Jane Asher Wooden Rolling Pin - Preparation Equipment - Jane Asher's Kitchen
hi Nigel - that's a cool baffle - are you thinking of using the handles of that rolling pin for phase plugs? - a Goldwood 18" GW1858 should work - the little Monacor tweeter is available at MCM Monacor Tweeter 1/2" Mini 8 Ohm | DT-74/8 (DT748) | Monacor
I choose the Monacor as it looked on paper to need very little work and is cheap. The idea being they can be used for other things later. Although very small they seem very OK. I will not be in a rush to change them. They suit 5 K two pole, very unusual for a cheap device to be against the norm ( 2 K ) . As it is I am at 10 K one pole. I guess it could go to 7 K one pole. The 10 K idea came from the old Spendor BC1 and it's old AKG /STC/ITT/Cole 4001G surper tweeter. Spendor used it to get the full BBC licence ( > 15 kHz for 625 line 15625 line buzz ). I am told > 7 kHz is ideal. As the 12 Lta has a little output at 7 kHz as would the tweeter they should blend as is to give a good 7 kHz output. In phase so as not to cause cancellation at the crossover point. It sounds as if it is correct. Not at all harsh. The 12 Lta has it's quack as anyone would imagine. 70% of the time it is OK. The speakers is a 4 way design, however that is not really correct. The 12 LTA doing 80 % of the work. I suspect the crossover frequencies do as little harm as is possible. The wizzer both good and bad. The good is no components to get it to crossover. It passes my Caruso test. That is where all the music is made or ruined.
The rolling pin offers 2 options. Cylinder or nose. The big surprize from my simple phase plug test was it can make a difference and seemed not too critical. It was the right type of change in that it is subtle. I will try suspending it. If it misses the dust cap by 1/8 inch it should still work from my earlier test. I use metric at work. How nice to use inches again. The French tell me it means thumbs. That seems about right if feet are feet. They did use inches and some old people still can. The still call 500 gms one pound.
I have been thinking of building these for maybe 30 years now. As crude as they are at least I have taken my first two steps, the 15 inch recently fitted. I was wrong about most of it. I wasn't wrong to try. All I will say to anyone is keep it simple and if it sounds wrong look at the mechanical side first. Filtering retains the problem albeit reduced in output. If one filters to enhance that is OK. Power handeling or to reduce exsessive output for example.
The rolling pin offers 2 options. Cylinder or nose. The big surprize from my simple phase plug test was it can make a difference and seemed not too critical. It was the right type of change in that it is subtle. I will try suspending it. If it misses the dust cap by 1/8 inch it should still work from my earlier test. I use metric at work. How nice to use inches again. The French tell me it means thumbs. That seems about right if feet are feet. They did use inches and some old people still can. The still call 500 gms one pound.
I have been thinking of building these for maybe 30 years now. As crude as they are at least I have taken my first two steps, the 15 inch recently fitted. I was wrong about most of it. I wasn't wrong to try. All I will say to anyone is keep it simple and if it sounds wrong look at the mechanical side first. Filtering retains the problem albeit reduced in output. If one filters to enhance that is OK. Power handeling or to reduce exsessive output for example.
I tried a little idea that had some value. I took a couple of sponges used for washing up the dishes and held them in place with the parcel tape ( 3 x 2x 4 inches ). It just about worked. I even adjusted it to hold them firm in the wizzers, this works better than I guessed. It makes a difference. However the colouration I hear seems the cone material more than standing waves. Baffle is part of it also. Looking on graphs of 12 LTa without wizzer it looks very similar. This ignores one thing. The wizzer must be a phase plug in it's own right and may be doing a very good job. Having put a 500 uH choke in the way the sound is still mostly the same except boring. Now that is no surprize. 200 uH might have worked.
I will remove the dust cap . I will get brave and coat the wizzer with PVA wood glue. This should mimic a 200 uH choke and reduce colouration if my hunch is right? Systems pulled out of resonance sometimes become faster. That would be nice.
I also put a sheet of kitchen towel across the wizzer. This did a little. A nylon stocking perhaps?
I will remove the dust cap . I will get brave and coat the wizzer with PVA wood glue. This should mimic a 200 uH choke and reduce colouration if my hunch is right? Systems pulled out of resonance sometimes become faster. That would be nice.
I also put a sheet of kitchen towel across the wizzer. This did a little. A nylon stocking perhaps?
1-4khz is probably the issue.
It is hot even 30 degrees off axis.
Probably due to funneling of the cone and cross section.
Whizzer helps dispersion an octave above cone, maybe up to 2.4khz.
Have you seen the plots recorded over at speakerplans.com ?
Try playing with a 10 band eq.
It is hot even 30 degrees off axis.
Probably due to funneling of the cone and cross section.
Whizzer helps dispersion an octave above cone, maybe up to 2.4khz.
Have you seen the plots recorded over at speakerplans.com ?
Try playing with a 10 band eq.
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To go with my twin 12-250 I built this sub using a Fane Sovereign 15-600LF.
An externally hosted image should be here but it was not working when we last tested it.
I got brave and did a halfway house modification. Tapping the centre of the 12 Lta driver with my finger it has a nasty sound. It is made from hard paper more like a yoghurt pot style of plastic. As the next step would be to cut it out why not some PVA glue? None to the wizzer. The type is standard non waterproof Evostick brand in the blue bottle. From the word go a nicer sound ( One coat then two lighter coats, a little water to help it spread ). More open and natural sound with noticable depth. I suspect the glue is damping rather than solidity. I think this confirms it is not air trapped behind the cap ( it has a vent anyway ). It is the cap. I suspect it will be better to remove it. For now I am very happy with the mod. What I haven't lost is the energy of the sound.
I discovered this idea perhaps more than 30 years ago when repairing a 1940's radio. It was a birthday surprise for a lady callled Jan, she had a identical one that got smashed. The PVA repair to a badly ripped cone using Rizla papers. It also had a big sound after the repair with no trade offs. I recently did the same for my bathroom radio ( and damping ). The smallest speaker in the largest box I have ever seen. It has moments now when it sounds very OK. The whole radio cost $15. It was awful before the mods. 20 mins work to do. As it ages it gets better. I did not paint the surround or centre on the < 1.5 inch cone. Idea being, too much is too much.
Back to Jans radio. It looked the same but wasn't as the one she had. There was a larger output valve. A war time adaption. My brother increased the bass, it had been reduced to stop the cabinet vibrating. We added BAF damping to help it deal with that. The sound was the very best I ever remember for this style of small radio. Size of a medium sized car battery from a smaller car. AM can sound very good when using high grade circuits.
I discovered this idea perhaps more than 30 years ago when repairing a 1940's radio. It was a birthday surprise for a lady callled Jan, she had a identical one that got smashed. The PVA repair to a badly ripped cone using Rizla papers. It also had a big sound after the repair with no trade offs. I recently did the same for my bathroom radio ( and damping ). The smallest speaker in the largest box I have ever seen. It has moments now when it sounds very OK. The whole radio cost $15. It was awful before the mods. 20 mins work to do. As it ages it gets better. I did not paint the surround or centre on the < 1.5 inch cone. Idea being, too much is too much.
Back to Jans radio. It looked the same but wasn't as the one she had. There was a larger output valve. A war time adaption. My brother increased the bass, it had been reduced to stop the cabinet vibrating. We added BAF damping to help it deal with that. The sound was the very best I ever remember for this style of small radio. Size of a medium sized car battery from a smaller car. AM can sound very good when using high grade circuits.
yup, my guy got wood (birch ply 3/4" 11-13 layers), and the place cut everything.
I'm putting the fane in a 12" deep x 19" tall x 29" wide box that'll slide under the "couch table" that my tv sits on.
I'm hoping a bunch of new better opamps will make my active crossover tolerable, so then I can cross to my ppsl at 100hz.
If not, guess I run the spkr under tv wide open, and fight on getting the sub to vanish.
I'm tired of watching stuff (like Better Call Saul) and the voices are 3' to the right of the tv.
Down the road (if I don't keep rearranging) I'll get some left/rights built, maybe a single cap crossed as tweets (that I will burn up, lol), then the surround preamp.
But for now, I'm excited.
I'm putting the fane in a 12" deep x 19" tall x 29" wide box that'll slide under the "couch table" that my tv sits on.
I'm hoping a bunch of new better opamps will make my active crossover tolerable, so then I can cross to my ppsl at 100hz.
If not, guess I run the spkr under tv wide open, and fight on getting the sub to vanish.
I'm tired of watching stuff (like Better Call Saul) and the voices are 3' to the right of the tv.
Down the road (if I don't keep rearranging) I'll get some left/rights built, maybe a single cap crossed as tweets (that I will burn up, lol), then the surround preamp.
But for now, I'm excited.
https://www.youtube.com/watch?v=0z5z5lwiS08
I revised my crossover if I dare call it that using 1100 uF to the 12 Lta. All it does is reduce the need for bass EQ. On balance a good idea. Sadly it didn't give me the extra warmth I would like. The first change to the 12 Lta did. 3 inch phase plug next. Might try a fabric covered jar. The screw on lid helps. If the jar is about 1.5 inch I can try more or less fabric. A Pesto jar perhaps?
PVA glue looks great. Lifts the looks a bit over matt paper.
I revised my crossover if I dare call it that using 1100 uF to the 12 Lta. All it does is reduce the need for bass EQ. On balance a good idea. Sadly it didn't give me the extra warmth I would like. The first change to the 12 Lta did. 3 inch phase plug next. Might try a fabric covered jar. The screw on lid helps. If the jar is about 1.5 inch I can try more or less fabric. A Pesto jar perhaps?
PVA glue looks great. Lifts the looks a bit over matt paper.
I think that's right. The baffle step is one problem and the 12 LTa is making it worse. To my great surprise as shown here is nicely balanced. The PVA wood glue seems to have sorted out the shouting upper mid. I have slightly risked the tweeter by setting - 3 dB at 6 kHz, Monacor prefer two pole when 5 kHz. The Quad is 40 watts and only 10 watts mid band due to EQ perhaps. At half volume it is above concert level, this means the tweeter will never see 0.5 watt ? The treble EQ is from 7 kHz and about + 6dB 20 kHz. This sounds very neutral and perhaps more so than the Quad ESL 63's that can sound dull. Bass is rather good and clearly shows when recorded quality is more accurate. Opera to 70's rock work very well as do things like the 8 bit Beatles ( almost detailed ! ). Caruso works and that was the starting point. 1930's 78's are very wonderful, so much detail and bass detail at that.
Capacitor coupling greatly helps high power use. No chance of DC . The damping factor of my set up will be poor. This seems to help and mimics current drive a bit. I use very thin cables ( 7 x 0.2 ) as a choice. Solid core also.
The strange thing is it's only the last changes that made it pull into focus.
BTW. I have gone out of my way to use junk box parts. All of the electrolytics are industrial types. The 1000 uF cost me $0.17 as a clearout. I can tell you right now some expensive output transformers cause me more doubt , a Sowter for an 845 for example. The tweeter caps are high grade but still only cost pennies. The tweeters are far better than I thought they would be.
For reasons I can not work out the marriage of the tweeter to the lightly modified 12 Lta has worked ( I use 3 very small acoustic rubber wizzer dampers also ). No longer a hollow sound nor colouration. I have met this before. I didn't expect the cure to be this easy. I image the polar responce is a lot to do wilth it. This is what I wanted. A baffle Dynaco A25 where brake frequency is 7 kHz rather than in the more sensetive 2 kHz region. The Dynaco also seems unlikely to work until tried. Although old fashioned sound A25 can really give music once the brain filter kicks in. That is it's faults fade away. Some speakers get worse the more you know them. To me usually plastic cones or metal ones do this.
Poulenc's Champetre was stunning. Renata Tebaldi also. The March Past of the Kitchen Utensils as I remeber it on Bafle speaker 50 years ago.
Capacitor coupling greatly helps high power use. No chance of DC . The damping factor of my set up will be poor. This seems to help and mimics current drive a bit. I use very thin cables ( 7 x 0.2 ) as a choice. Solid core also.
The strange thing is it's only the last changes that made it pull into focus.
BTW. I have gone out of my way to use junk box parts. All of the electrolytics are industrial types. The 1000 uF cost me $0.17 as a clearout. I can tell you right now some expensive output transformers cause me more doubt , a Sowter for an 845 for example. The tweeter caps are high grade but still only cost pennies. The tweeters are far better than I thought they would be.
For reasons I can not work out the marriage of the tweeter to the lightly modified 12 Lta has worked ( I use 3 very small acoustic rubber wizzer dampers also ). No longer a hollow sound nor colouration. I have met this before. I didn't expect the cure to be this easy. I image the polar responce is a lot to do wilth it. This is what I wanted. A baffle Dynaco A25 where brake frequency is 7 kHz rather than in the more sensetive 2 kHz region. The Dynaco also seems unlikely to work until tried. Although old fashioned sound A25 can really give music once the brain filter kicks in. That is it's faults fade away. Some speakers get worse the more you know them. To me usually plastic cones or metal ones do this.
Poulenc's Champetre was stunning. Renata Tebaldi also. The March Past of the Kitchen Utensils as I remeber it on Bafle speaker 50 years ago.
hi Nigel - did you dilute the PVA? - was the whizzer coated inside and out? - how does Del Monaco sound on this speaker? - (do you also listen to Kozlovsky?) - how about solo classical piano? (I wish the Fane were available with a stronger motor - it plays very clear in the mids with no noticeable artifacts in my Karlsons) some years ago I ran 12LTA with a cheap 21" woofer on 24x48" baffle
I hope Fane users can see many things here for them. I used I guess 10 % water with PVA. Three coats, the last two thinner. That is easy as the second and third coats go on thinner. It was to the outside only and only the dome. Looks rather good.
Piano is stunning. Del Monaco is powerful with great tonality. Tosca is certainly what he can sing. De Stephano and Caruso also come to mind to compare. Kovlovsky Song of the Indian guest. Strangely Heddle Nash comes to mind. How they sung in their own mother tongue with pride, unforced. Unreal how good. Thanks for saying.
Fane was something we sold in the 1980's . Small TV types at about $3. To be honest they were a make we didn't think much of. I now realise they made what people wanted at a very low price. The Fane of now I think is Chinese and not Batley Yorkshire ?
Piano is stunning. Del Monaco is powerful with great tonality. Tosca is certainly what he can sing. De Stephano and Caruso also come to mind to compare. Kovlovsky Song of the Indian guest. Strangely Heddle Nash comes to mind. How they sung in their own mother tongue with pride, unforced. Unreal how good. Thanks for saying.
Fane was something we sold in the 1980's . Small TV types at about $3. To be honest they were a make we didn't think much of. I now realise they made what people wanted at a very low price. The Fane of now I think is Chinese and not Batley Yorkshire ?
I sat close and my APT80 tweeter probably was too high above 12lta so their was a spatial "disconnect" noticeable on percussion harmonics - perhaps a time problem too (?) so changed to Beta12cx for awhile before dismantling the baffle. That Monacor tweeter which Nigel uses sounds like it works well. Maybe Dayton's revival of the old CTS "phenolic ring" tweeter would be nice with 12lta.
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The Monacor would be like the stop gap car you buy and keep 10 years.
I shall borrow a Rotel RA 931 budget amp I fixed recently to see how it does. I have a hunch it will work fine. I based this idea on standard amps with tone controls. I fancy a Sugden A48 would be best of all. That is from Fane country. If the amp has the option 7 kHz turnover is slightly better, 10 kHz is fine. I imagine NAD 3020 would be fine. These amps have enough power and none mind 3 ohms. Sony TA5650 would be fun. Dynaco ST70 would cope. The Yamaha class A or AB amps. Marantz Model 9. The Sugden would be top of my list for value. If I get my camera talking to the computer again I must show the set up. The build is very simple. 12 Lta in the exact middle. 15 inch in the space below the 12 Lta ( 2 inch gap ). Tweeter also 2 inch gap above 12 Lta. 2 x 4 foot baffle 1 inch deep made from 1/2 inch ply and MDF. The old Hitach power amp design should be ideal. I was sent some PCB's a friend had made from my old artwork for the Hitachi, maybe that is telling me something? She is a trained Opera singer, when she is in the mood she sings Mahler for me! She has recently rebuilt her Jaguar 3.2 litre engine!
A Yorkshire lady singing the same.
https://www.youtube.com/watch?v=Md-JfajEtzM
I shall borrow a Rotel RA 931 budget amp I fixed recently to see how it does. I have a hunch it will work fine. I based this idea on standard amps with tone controls. I fancy a Sugden A48 would be best of all. That is from Fane country. If the amp has the option 7 kHz turnover is slightly better, 10 kHz is fine. I imagine NAD 3020 would be fine. These amps have enough power and none mind 3 ohms. Sony TA5650 would be fun. Dynaco ST70 would cope. The Yamaha class A or AB amps. Marantz Model 9. The Sugden would be top of my list for value. If I get my camera talking to the computer again I must show the set up. The build is very simple. 12 Lta in the exact middle. 15 inch in the space below the 12 Lta ( 2 inch gap ). Tweeter also 2 inch gap above 12 Lta. 2 x 4 foot baffle 1 inch deep made from 1/2 inch ply and MDF. The old Hitach power amp design should be ideal. I was sent some PCB's a friend had made from my old artwork for the Hitachi, maybe that is telling me something? She is a trained Opera singer, when she is in the mood she sings Mahler for me! She has recently rebuilt her Jaguar 3.2 litre engine!
A Yorkshire lady singing the same.
https://www.youtube.com/watch?v=Md-JfajEtzM