68uF Solens
DM,
I really think that using only 68uF in both positions of the bass filter may not be sufficient.
Use 68uF in the electrically parallel to woofer position and 75uF in the centre leg of the filter T position,
if you do not want to use all 75uF caps or parallel 36uF pairs to 72uF.
If you haven't soldered in those 68uF caps yet, I recommend you send two back and exchange for two 75uF caps -
one for each crosover.
DM,
I really think that using only 68uF in both positions of the bass filter may not be sufficient.
Use 68uF in the electrically parallel to woofer position and 75uF in the centre leg of the filter T position,
if you do not want to use all 75uF caps or parallel 36uF pairs to 72uF.
If you haven't soldered in those 68uF caps yet, I recommend you send two back and exchange for two 75uF caps -
one for each crosover.
and then the L-pad again
Hello Stuart,
well, every New Year is getting a bit more "preposterous" for most of us as humans continue in the various ways that we do !
After you install the poly caps you will likely hear that the L-pads need to be adjusted again.
Given the different midrange balances of different recordings you likely will not find a single setting that sounds optimum for every recording.
I recommend that you not try to balance the midrange with reference to Top 40 type Pop recordings or substantially commercialised easy listening MOR recordings,
but better is to use naturally recorded material including acoustic instruments, whether Folk musics or Classical, and with vocals that have not had artificial production effects added to them.
Then listen to your favorite recordings of whatever type.
You may find two somewhat different settings, and if so then write down the resistances for both of them.
Being L-pads, there are two different electrical aspects that are being adjusted, and thus you may hear a trade-off of one type of audible effect versus another type.
Post reports of whatever you hear in both the upper and lower midrange after you have done comprehensive listening.
Comment on whatever you think may be reasonably further achieved.
If you haven't seen already, then do look at sba's posts of the drivers' impedance plots - on Page 36 in #354 and #355, and my point to you in #357.
The L-pads are changing those varying with frequency lower midrange impedances -{whichever is closest to the impedance of your driver samples}- in relation to what the crossover filter sees.
I will post more about this after more feedback from the interested persons.
Hello Stuart,
well, every New Year is getting a bit more "preposterous" for most of us as humans continue in the various ways that we do !
After you install the poly caps you will likely hear that the L-pads need to be adjusted again.
Given the different midrange balances of different recordings you likely will not find a single setting that sounds optimum for every recording.
I recommend that you not try to balance the midrange with reference to Top 40 type Pop recordings or substantially commercialised easy listening MOR recordings,
but better is to use naturally recorded material including acoustic instruments, whether Folk musics or Classical, and with vocals that have not had artificial production effects added to them.
Then listen to your favorite recordings of whatever type.
You may find two somewhat different settings, and if so then write down the resistances for both of them.
Being L-pads, there are two different electrical aspects that are being adjusted, and thus you may hear a trade-off of one type of audible effect versus another type.
Post reports of whatever you hear in both the upper and lower midrange after you have done comprehensive listening.
Comment on whatever you think may be reasonably further achieved.
If you haven't seen already, then do look at sba's posts of the drivers' impedance plots - on Page 36 in #354 and #355, and my point to you in #357.
The L-pads are changing those varying with frequency lower midrange impedances -{whichever is closest to the impedance of your driver samples}- in relation to what the crossover filter sees.
I will post more about this after more feedback from the interested persons.
Last edited:
66's done
Could not post with a quote.
C3&4 are a single clarity 3.9 . C 1&2 are a single clarity 6.0 with a 0.5 R between the cap and the spkr. C5 is a clarity 3.9 with a 3.3 R in series. C7 is a 25 clarity with a 1.8R in series. C6 is a Solen 68 with a 1.5R in series. C8 is a 75 Solen with a 1.0R in series. My old age hearing and sight doesnt hear too much difference.
One MD 500 is not up too snuff (IMHO) eaven after installing a NOS coil/diaghram. Had to add extensions to the leads for C8 so as to clear the inductors.. Now, the board extends so far into the cabinet, that the 2 inch foam is tight to the back of the woofers. Will this affect the way they operate/sound? Probalbly some pressure on all the big solen caps as well. I was just happy they all worked, although now one woofer has a hiss at certain frequencies. (sounds like a record scratch). thought it might be a wire connection fault due to vibration but cant confirm.
thanks for all the advice on what to buy & where it goes. But seems the more I try to *fix*, the more it breaks. Except for the weak mid, the hiss on the woofer, all is functioning. Speaker system B is good.
Could not post with a quote.
C3&4 are a single clarity 3.9 . C 1&2 are a single clarity 6.0 with a 0.5 R between the cap and the spkr. C5 is a clarity 3.9 with a 3.3 R in series. C7 is a 25 clarity with a 1.8R in series. C6 is a Solen 68 with a 1.5R in series. C8 is a 75 Solen with a 1.0R in series. My old age hearing and sight doesnt hear too much difference.
One MD 500 is not up too snuff (IMHO) eaven after installing a NOS coil/diaghram. Had to add extensions to the leads for C8 so as to clear the inductors.. Now, the board extends so far into the cabinet, that the 2 inch foam is tight to the back of the woofers. Will this affect the way they operate/sound? Probalbly some pressure on all the big solen caps as well. I was just happy they all worked, although now one woofer has a hiss at certain frequencies. (sounds like a record scratch). thought it might be a wire connection fault due to vibration but cant confirm.thanks for all the advice on what to buy & where it goes. But seems the more I try to *fix*, the more it breaks. Except for the weak mid, the hiss on the woofer, all is functioning. Speaker system B is good.
hearing and listening
Hello DM,
its good to see tha you have got your caps and resistors correctly placed.
Don't convince yourself that "old age hearing and sight doesn't hear too much difference" - you might be surprised what some older listeners do hear despite audiologists' tests on them which show some high frequencies reduction, because Listening is different to merely Hearing !
Put the Theory out of your mind, and play some of your favorite recordings, and over a period of time you may be surprised at what you come to realize you are hearing.
For some listeners, thinking about sound differences too much only confuses the issue because their particular technical understandings get in the way of other types of perception.
Right brain versus Left brain - its true - it happens to me !
I'll post about the audible faults in your woofer and MD500 next time, as I have to go now, BUT in the mean-time play your 66s a lower volume so as to not do any damage !
Look back earlier in this Thread for the posts by tonedef2, and another member who published photographs of the internals of his MD500, and read what both state about MD500 deterioration.
Hello DM,
its good to see tha you have got your caps and resistors correctly placed.
Don't convince yourself that "old age hearing and sight doesn't hear too much difference" - you might be surprised what some older listeners do hear despite audiologists' tests on them which show some high frequencies reduction, because Listening is different to merely Hearing !
Put the Theory out of your mind, and play some of your favorite recordings, and over a period of time you may be surprised at what you come to realize you are hearing.
For some listeners, thinking about sound differences too much only confuses the issue because their particular technical understandings get in the way of other types of perception.
Right brain versus Left brain - its true - it happens to me !
I'll post about the audible faults in your woofer and MD500 next time, as I have to go now, BUT in the mean-time play your 66s a lower volume so as to not do any damage !
Look back earlier in this Thread for the posts by tonedef2, and another member who published photographs of the internals of his MD500, and read what both state about MD500 deterioration.
several points to consider
DM, and anyone else interested, I have numbered some points in the Quote Box which I will address below it.
[/B]
(1) - this is good because we are not trying to change the basic sound of what was a good design originally.
We are trying to restore the original sound, and only add a bit of clarity that was not possible with the old electrolytic caps.
I think you have likely got the ESR simulated very close to the original, thus now you have a modern Celestion 66.
Continue listening as I described in my last post above - that is, don't think about the sound whilst listening, but simply listen to the music, and not to the sound of the loudspeakers.
(2) - look back through the thread till you find tonedef2, then open his contact details' file and email to him.
He may still have some one or two of those NOS MD500s for sale,
or, he may agree to restore your MD500 to good working condition for a reasonable fee.
He has the understanding of how it works, and the manual skills necessary to do the job.
(3) - how tight ?
If pressed very tight, then cut away some of the foam so that it only touches the driver and crossover.
It can be left to compress a little with small pressure to the driver and crossover, but NOT with strong pressure, because the chassis of older drivers was not made to support pressure - pressure on it may cause another part of it to move the voice-coil's chamber slightly OR even to cause the internal of the magnet assembly to touch the voice-coil,
OR, if there is a small crack starting in the Spider or the Surround or the Cone, any forced displacement of such area may be the cause of the scratch sound you are hearing.
(4) - cut away a small part of the foam so that it only touches the caps lightly.
Excess pressure may cause the soldered joints to crack, particually if the speaker is played loudly as there will be then a lot of fast-shock vibrations inside the cabinet.
(5) - inspect all the visible surfaces of the woofer's cone, and its outer surround, and the dust-cap joining circle to the cone.
Use a magnifying glass, and look for tiny cracks or tiny holes.
Do not push on any cracks in the outer edge surround, because when that surround substance deteriorates it becomes fragile and may break worse.
You can push lightly on the dust cap as it is strong material, but watch closely there to see if it then moves away from the cone's surface.
Post here whatever you find.
I have forgotten how the wire leads are connected to the voice-coils of those drivers, but some Celestion drivers have the wires connected to 2 points on the back of the cone, and then wire from those is routed to the voice-coil.
Look closely at the back of the cone, and inspect any connecting areas with a magnifying glass.
Do not pull hard on any wires, because if the old adhesive has deteriorated part of the cone may tear there.
(6) - describe this "weak mid" sound ... is it only low output volume, or is the tone very different to that of the other MD500 ?
DM, and anyone else interested, I have numbered some points in the Quote Box which I will address below it.
[/B]
(1) - this is good because we are not trying to change the basic sound of what was a good design originally.
We are trying to restore the original sound, and only add a bit of clarity that was not possible with the old electrolytic caps.
I think you have likely got the ESR simulated very close to the original, thus now you have a modern Celestion 66.
Continue listening as I described in my last post above - that is, don't think about the sound whilst listening, but simply listen to the music, and not to the sound of the loudspeakers.
(2) - look back through the thread till you find tonedef2, then open his contact details' file and email to him.
He may still have some one or two of those NOS MD500s for sale,
or, he may agree to restore your MD500 to good working condition for a reasonable fee.
He has the understanding of how it works, and the manual skills necessary to do the job.
(3) - how tight ?
If pressed very tight, then cut away some of the foam so that it only touches the driver and crossover.
It can be left to compress a little with small pressure to the driver and crossover, but NOT with strong pressure, because the chassis of older drivers was not made to support pressure - pressure on it may cause another part of it to move the voice-coil's chamber slightly OR even to cause the internal of the magnet assembly to touch the voice-coil,
OR, if there is a small crack starting in the Spider or the Surround or the Cone, any forced displacement of such area may be the cause of the scratch sound you are hearing.
(4) - cut away a small part of the foam so that it only touches the caps lightly.
Excess pressure may cause the soldered joints to crack, particually if the speaker is played loudly as there will be then a lot of fast-shock vibrations inside the cabinet.
(5) - inspect all the visible surfaces of the woofer's cone, and its outer surround, and the dust-cap joining circle to the cone.
Use a magnifying glass, and look for tiny cracks or tiny holes.
Do not push on any cracks in the outer edge surround, because when that surround substance deteriorates it becomes fragile and may break worse.
You can push lightly on the dust cap as it is strong material, but watch closely there to see if it then moves away from the cone's surface.
Post here whatever you find.
I have forgotten how the wire leads are connected to the voice-coils of those drivers, but some Celestion drivers have the wires connected to 2 points on the back of the cone, and then wire from those is routed to the voice-coil.
Look closely at the back of the cone, and inspect any connecting areas with a magnifying glass.
Do not pull hard on any wires, because if the old adhesive has deteriorated part of the cone may tear there.
(6) - describe this "weak mid" sound ... is it only low output volume, or is the tone very different to that of the other MD500 ?
Last edited:
Alan: I cut away about half the thickness of the foam. It had slight indentations from whatever pieces it had pressure on. Inspected the woofer Could not see any tears, holes etc. Leads all look good. Did have a loose terminal post entering the spkr, fixing this did not eliminate the hiss. the weak mid seems to be low out. vol compared to the other. (not tone). But for sure, I do hear clarity now. guess I'll just keep looking for a mid and a bass . havent got in touch with def2 yet.
Translation ?
Hi Doug,
I am wondering if we may have a problem with translating from your first language ?
In Alberta there is French{Francaise} and German{Deutsch} and others.
I am not sure of the sound you describe as "hiss".
In English language, "hiss" sound is the vocal sound made by a snake or serpent,
and is also the sound one hears when an old amplifier's volume is turned up when there is no signal present,
and is also the sound one hears when a Radio is in between stations and not tuned to any signal,
and that sound is like White Noise {bruit blanc}.
But also you wrote "sounds like a record scratch" ... is this sound also like a very short duration of tearing or ripping of paper ?
Francaise --> English:- "siffler" = "hiss", but "siffler" = "whistle" also !
Francaise --> English:- "gratter" = "scratch" & "scrape" & "rub".
Deutsch - I do not know, but I may have a Dictionary somewhere ...
Post words for the sound in your first language.
I think I can guess what the problem may be, but I want to be sure, because there are two possibilities.
For now, do not play the speaker too loud ... so as to not to cause damage till we solve this problem.
Hi Doug,
I am wondering if we may have a problem with translating from your first language ?
In Alberta there is French{Francaise} and German{Deutsch} and others.
I am not sure of the sound you describe as "hiss".
In English language, "hiss" sound is the vocal sound made by a snake or serpent,
and is also the sound one hears when an old amplifier's volume is turned up when there is no signal present,
and is also the sound one hears when a Radio is in between stations and not tuned to any signal,
and that sound is like White Noise {bruit blanc}.
But also you wrote "sounds like a record scratch" ... is this sound also like a very short duration of tearing or ripping of paper ?
Francaise --> English:- "siffler" = "hiss", but "siffler" = "whistle" also !
Francaise --> English:- "gratter" = "scratch" & "scrape" & "rub".
Deutsch - I do not know, but I may have a Dictionary somewhere ...
Post words for the sound in your first language.
I think I can guess what the problem may be, but I want to be sure, because there are two possibilities.
For now, do not play the speaker too loud ... so as to not to cause damage till we solve this problem.
Last edited:
Hi Alan - I'm still waiting to hear from Falcon Acoustics re 70uF poly caps. I haven't responded earlier as I'm finding this forum can be a nightmare to try and log on or use quotes.
Meantime, I've got the L-pads at a setting which seems pretty good to me on both simple recordings and more 'processed' stuff. The main criticism I have now is still that little hump in the upper bass/lower mid. I expect I'll have other gripes if this hump can be partly resolved. Perhaps each improvement unmasks smaller and smaller problems.
The L-pads were set purely by listening but coincidentally the wiper is exactly half way round its travel. Disconnected from the crossover, Pin 1 to 2 gives 19 ohms and Pin 2 to 3 gives 6 ohms.
This setting gives me what I think is a good balance between the drivers. I do wonder how an in room frequency response graph would look compared to the original design. The designer is probably shaking his head in despair.
Meantime, I've got the L-pads at a setting which seems pretty good to me on both simple recordings and more 'processed' stuff. The main criticism I have now is still that little hump in the upper bass/lower mid. I expect I'll have other gripes if this hump can be partly resolved. Perhaps each improvement unmasks smaller and smaller problems.
The L-pads were set purely by listening but coincidentally the wiper is exactly half way round its travel. Disconnected from the crossover, Pin 1 to 2 gives 19 ohms and Pin 2 to 3 gives 6 ohms.
This setting gives me what I think is a good balance between the drivers. I do wonder how an in room frequency response graph would look compared to the original design. The designer is probably shaking his head in despair.
Hello Stuart,
perhaps the Falcon staff are on holidays, or perhaps they don't want to do the measuring.
My experience -{with other companies}- is whether or not a non-technical knowledge staff-person will measure something depends very much whether they understand what the questioner is asking, and/or whether they think there will be a sale involved to make their time spent worth it.
Also, some technical people don't consider a less than +/- 5% difference in capacitance to be audibly significant for a loudspeaker crossover,
-{though they would consider it significant for making a tuned filter for R.F. application}.
Getting an answer also depends very much on how the question is asked,
thus why I PM'd you a Draft for the question,
and, they have to understand from the email that you do seriously want to buy.
Try a follow-up email on Monday, and phrase it strategically !
{but don't write as if annoyed at receiving no reply}.
If no reply soon, post again and I'll list the French seller of 36uF - to use as a parallel pair to sum to 72uF in each position.
*********************************************************
L-pad:-
6 ohm is very large for the series leg !
Either you don't like hearing much midrange, or there is another problem with the drivers ...
If no other problem with the drivers, then as you have attenuated the mid-drivers so much you will substantially hear that upper-bass/low-mids' resonance from the woofer.
Given the non-linear wrt SPL way the human ear/brain works, the frequency spectrum sounds different at different volume levels,
thus do the fine-tuning at a realistic listening level that is not the quietest level that has to be sometimes used, nor the loudest sometimes' use level,
because you will find the difference between L-pads' settings for those extremes will be large.
For your previous electrical location of the L-pads you posted only 1 ohm for the series leg.
The electrical location now will give a different compromise resistance, though it shouldn't be as high as 6 ohms ... however you are entitled to your preferences !
Try again as above, but you may as well not decide finally till after you hear with the poly caps fitted.
*********************************************************
I don't know enough about computer systems to know why you are encountering problems with ease of use of this site, but it may be a regional access/transmission problem ... do you have similar problems with any other web-sites ?
perhaps the Falcon staff are on holidays, or perhaps they don't want to do the measuring.
My experience -{with other companies}- is whether or not a non-technical knowledge staff-person will measure something depends very much whether they understand what the questioner is asking, and/or whether they think there will be a sale involved to make their time spent worth it.
Also, some technical people don't consider a less than +/- 5% difference in capacitance to be audibly significant for a loudspeaker crossover,
-{though they would consider it significant for making a tuned filter for R.F. application}.
Getting an answer also depends very much on how the question is asked,
thus why I PM'd you a Draft for the question,
and, they have to understand from the email that you do seriously want to buy.
Try a follow-up email on Monday, and phrase it strategically !
{but don't write as if annoyed at receiving no reply}.
If no reply soon, post again and I'll list the French seller of 36uF - to use as a parallel pair to sum to 72uF in each position.
*********************************************************
L-pad:-
6 ohm is very large for the series leg !
Either you don't like hearing much midrange, or there is another problem with the drivers ...
If no other problem with the drivers, then as you have attenuated the mid-drivers so much you will substantially hear that upper-bass/low-mids' resonance from the woofer.
Given the non-linear wrt SPL way the human ear/brain works, the frequency spectrum sounds different at different volume levels,
thus do the fine-tuning at a realistic listening level that is not the quietest level that has to be sometimes used, nor the loudest sometimes' use level,
because you will find the difference between L-pads' settings for those extremes will be large.
For your previous electrical location of the L-pads you posted only 1 ohm for the series leg.
The electrical location now will give a different compromise resistance, though it shouldn't be as high as 6 ohms ... however you are entitled to your preferences !
Try again as above, but you may as well not decide finally till after you hear with the poly caps fitted.
*********************************************************
I don't know enough about computer systems to know why you are encountering problems with ease of use of this site, but it may be a regional access/transmission problem ... do you have similar problems with any other web-sites ?
language
thanks Alan. just finished (again) trying to decipher the sound. first, I have no other language than *Anglais*. Upon reflection, a record scratch may have more of a *tic* than a *sss*. My woofer may be more inclined to sound like the tearing of paper (as you asked). It can last for quite some time, & then disappear for a while. Seems to be freq.&/or volume dependent.
It can it occur with rock, folk, classical, - any kind of sound . Several nights ago, I thought the whole speaker was going to jump out of the cabinet, but I hit the mute real fast, which rectified the problem instantly.
there are 2 66 woofers on the *bay* watch right now close to home, for some cash, think I should maybe be watching them for a replacement?
thanks Alan. just finished (again) trying to decipher the sound. first, I have no other language than *Anglais*. Upon reflection, a record scratch may have more of a *tic* than a *sss*. My woofer may be more inclined to sound like the tearing of paper (as you asked). It can last for quite some time, & then disappear for a while. Seems to be freq.&/or volume dependent.
It can it occur with rock, folk, classical, - any kind of sound . Several nights ago, I thought the whole speaker was going to jump out of the cabinet, but I hit the mute real fast, which rectified the problem instantly.
there are 2 66 woofers on the *bay* watch right now close to home, for some cash, think I should maybe be watching them for a replacement?
66 woofers - faults and replacements
Hi DM,
first, if the woofers you are considering are the two offered by "phatstereo" of Burnaby BC, do NOT buy them, because they are NOT 66, or 44, woofers.
They are the later type used in Celestion's 442 and 662 loudspeakers.
If you try to use those you will have to design a new crossover because they have a higher impedance voice-coil, and will have a different frequency response in the crossover region as result of their coated cones.
Note their Part Number:- T.2937.
Celestion 44 and 66 specification woofers originally had the Part Number:- T.1600,
and the only suitable replacement woofer had the Part Number:- T.2619.
{each seems to be different only in its centre of cone, dust cap.}
Before you buy any woofers, ask the seller to inform you the T.**** number.
This number is printed on the back-chassis of all Celestion drivers.
*************************************************
About the fault-sound, if you have not already, then try now:-
(1) - swap the loudspeakers over - connect the faulty one to the other channel of your amplifier, and the non-faulty one to the amp channel which has been driving the faulty one.
Listen to sound carefully ... any difference ?
(2) - I doubt the fault is in the crossover, but to check that swap the woofers around - put the fault-sound woofer in the other 66 cabinet, and connect the non-fault woofer to the suspect crossover.
(3) - before you do the above, try also:-
lay the faulty driver's cabinet on its back with the woofer facing upwards, or, take the woofer out of cabinet and sit it facing upwards.
Form the fingers and thumb of one of your hands into the shape of a circle and place the the tips of fingers and thumb on the top surface of the woofer cone at equal distances around the dust cap.
Very gently press down and listen very carefully - do you hear a scratching or scraping sound ?
Press only in the direction that the cone moves when playing music.
Do not press slightly sideways, because that will cause the voice-coil to rub against the inside of the magnet surface.
Press down only about 1/4" -{6mm}- and then release hand pressure, and listen again.
Press down and release several times if you do not hear a sound the first time.
This must be done very gently with old Hi-Fi woofers, because if parts are deteriorating, breakage can easily occur.
{when this test is done with modern Hi-Fi woofers, and Public Address system woofers, and electric guitar speakers, it can be done more firmly because those drivers are all more robust}.
If you do hear a scratch or scrape sound, then do not continue pumping the cone in/out, especially if the sound is fairly loud, because the fault will get worse.
(4) - measure the DC resistance of the faulty woofer and the non-faulty woofer.
You will have to disconnect each woofer from its crossover to get accurate measurements.
Both should measure same or very close to same.
Post the ohms for each here.
(5) - try the same Press in/Release test on the ABR/passive radiator.
This unit is more robust, thus you can press with it remaining upright in-caninet.
I doubt that will be the source of the noise, but try it to be sure.
************************************************
Are you absolutely sure that fault sound is coming from the woofer, and not from the mid-dome ?
Hi DM,
first, if the woofers you are considering are the two offered by "phatstereo" of Burnaby BC, do NOT buy them, because they are NOT 66, or 44, woofers.
They are the later type used in Celestion's 442 and 662 loudspeakers.
If you try to use those you will have to design a new crossover because they have a higher impedance voice-coil, and will have a different frequency response in the crossover region as result of their coated cones.
Note their Part Number:- T.2937.
Celestion 44 and 66 specification woofers originally had the Part Number:- T.1600,
and the only suitable replacement woofer had the Part Number:- T.2619.
{each seems to be different only in its centre of cone, dust cap.}
Before you buy any woofers, ask the seller to inform you the T.**** number.
This number is printed on the back-chassis of all Celestion drivers.
*************************************************
About the fault-sound, if you have not already, then try now:-
(1) - swap the loudspeakers over - connect the faulty one to the other channel of your amplifier, and the non-faulty one to the amp channel which has been driving the faulty one.
Listen to sound carefully ... any difference ?
(2) - I doubt the fault is in the crossover, but to check that swap the woofers around - put the fault-sound woofer in the other 66 cabinet, and connect the non-fault woofer to the suspect crossover.
(3) - before you do the above, try also:-
lay the faulty driver's cabinet on its back with the woofer facing upwards, or, take the woofer out of cabinet and sit it facing upwards.
Form the fingers and thumb of one of your hands into the shape of a circle and place the the tips of fingers and thumb on the top surface of the woofer cone at equal distances around the dust cap.
Very gently press down and listen very carefully - do you hear a scratching or scraping sound ?
Press only in the direction that the cone moves when playing music.
Do not press slightly sideways, because that will cause the voice-coil to rub against the inside of the magnet surface.
Press down only about 1/4" -{6mm}- and then release hand pressure, and listen again.
Press down and release several times if you do not hear a sound the first time.
This must be done very gently with old Hi-Fi woofers, because if parts are deteriorating, breakage can easily occur.
{when this test is done with modern Hi-Fi woofers, and Public Address system woofers, and electric guitar speakers, it can be done more firmly because those drivers are all more robust}.
If you do hear a scratch or scrape sound, then do not continue pumping the cone in/out, especially if the sound is fairly loud, because the fault will get worse.
(4) - measure the DC resistance of the faulty woofer and the non-faulty woofer.
You will have to disconnect each woofer from its crossover to get accurate measurements.
Both should measure same or very close to same.
Post the ohms for each here.
(5) - try the same Press in/Release test on the ABR/passive radiator.
This unit is more robust, thus you can press with it remaining upright in-caninet.
I doubt that will be the source of the noise, but try it to be sure.
************************************************
Are you absolutely sure that fault sound is coming from the woofer, and not from the mid-dome ?
Last edited:
L-Pads again
Hi Alan - Falcon are changing premises and owners at the moment. They did say they can measure some 70uF poly caps for me so I'll just have to be patient until they're sorted.
As for the L-pads, my partner and I checked again to see which settings we prefer. Much more than half way (6 ohms on pins 2-3) and the sound begins to get muffled. Much less than half way and the mid can get a little aggressive with powerful voices such as Sinead O'Connor. To our ears, the 6 ohm setting seems to give a very agreeable balance between all 3 drivers on all the music I've listened to. The balance between mid and treble seems comparable to my Dynaudios, but without the sibilance and mid range hardness. I think the only thing the Dynaudios do better is to put human voices and acoustic instruments further into the room. Sometimes they just hang in space but even so, I still couldn't live with them permanently. All my other speakers sound too dominant in the mid, so maybe its my other gear or a room effect.
I just spent the last 3 hours listeng to a wide variety of music - K.D. Lang at a moderate level, Bob Marley and Gomez at a satisfying level and ACDC and Pink Floyd at a level which makes the meniscus on my red wine vibrate. My 66's have never sounded as good as they do just now but I'll try and get a third opinion from M4RK5 who lives nearby.
Hi Alan - Falcon are changing premises and owners at the moment. They did say they can measure some 70uF poly caps for me so I'll just have to be patient until they're sorted.
As for the L-pads, my partner and I checked again to see which settings we prefer. Much more than half way (6 ohms on pins 2-3) and the sound begins to get muffled. Much less than half way and the mid can get a little aggressive with powerful voices such as Sinead O'Connor. To our ears, the 6 ohm setting seems to give a very agreeable balance between all 3 drivers on all the music I've listened to. The balance between mid and treble seems comparable to my Dynaudios, but without the sibilance and mid range hardness. I think the only thing the Dynaudios do better is to put human voices and acoustic instruments further into the room. Sometimes they just hang in space but even so, I still couldn't live with them permanently. All my other speakers sound too dominant in the mid, so maybe its my other gear or a room effect.
I just spent the last 3 hours listeng to a wide variety of music - K.D. Lang at a moderate level, Bob Marley and Gomez at a satisfying level and ACDC and Pink Floyd at a level which makes the meniscus on my red wine vibrate
. My 66's have never sounded as good as they do just now but I'll try and get a third opinion from M4RK5 who lives nearby.
Alan: I noticed the different chasis number of *phatstereo* woofers, as well as the screw hole alignments. My woofs are 4.5 & 4.6 ohms. Could not hear any scraping/scratching with the finger tests. Switched channels for the woofs and now the previous good one has the *ssss*. Gotta be something in the xover. Definitely from the woof, not the mid. Guess I'll pull it out and go thru all connections etc.
'loper: is moderate *loud*, satisfying room pounding, and wine wiggling just at clipping?
'loper: is moderate *loud*, satisfying room pounding, and wine wiggling just at clipping?
'Moderate' is a realistic level for human voice, 'satisfying' is room filling and 'wine wiggling' is very, very loud. No clipping, just clear undistorted sound. Some systems seem to sound a bit congested as the volume goes up but I think the 66's are efficient enough to go very loud without approaching the power amps headroom limits or sounding at all strained. My Canadian Classe power amp is rated at 100w into 8 ohms, 200w into 4 ohms so I reckon 150w into 6 ohms. On my pre-amp I rarely go beyond 1/3 on the volume control, even with very loud music although it can go way past 11!
According to the reviews the power amp is a little on the polite side as far as bass is concerned. I think an amp with more bass could be quite scary...
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Celestion 66's
Hello to all those involved in this thread. It's been a lengthy read and I must confess to being overwhelmed by the technical aspects you have covered. I have no expertise to bring to the discussion, but I did want to thank you for reaffirming my faith in the Celestion 66's. I bought mine new in 1975 (for anyone interested, I paid $900 Australian). I had recently thought of selling them but when I had listened to a few other loudspeakers (up to $Aus 7000) I found that the 66's, for all their perceived faults, sounded like a true full-range speaker (and, depending on related equipment and a good recording, had touches of excellence). So I've decided to keep them and spend what I have to on their restoration. Hence my participation in this discussion. I have several questions that I hope someone will be kind enough to answer for me please. My 66's are series 1 'blackies'. More than a few years ago one of the original tweeters ceased functioning. Having no idea about anything I took the speakers to a repairer who replaced the tweeters with (what I have recently discovered to be) a no name brand. He also saw fit to bi-wire, reconfigure the Xover and update (some of) the capacitors. This is my first question: I understand, from reading this thread, that the original tweeters were not the best but replacing them would (probably) give rise to alterations to the Xover. However, given that this decision has already been taken out of my hands I'm now thinking of replacing the 'no-name's with Hickafon's (Hiquphon) OW1 or OW11. Is this a good idea? Second question: I have read previous advice contained in this thread about the 66 bass, ie. move the speakers away from walls/lift of the floor/block up the abr if it's annoying. However, I'm wondering if the Celestion woofers are worthy of being restored or are there better items now available? Third question: I've read, both here and on other internet forums, how good the MD500 midrange is. But because my 66's are the earlier series 1 they use the MF500. So, apart from the power rating, how do they rate vis a vis the MD500's? And again, like the woofer, are they a worthy item for restoration? Fourth question: Celestion sent me the original diagrams for the series 1 Xover's (also the series 11 and a pink noise test and some 66 publicity ads and reviews). Is it a good idea to have the Xovers rebuilt to original specifications but using upmarket (probably Hovland and Mundorf) capacitors and inductors and with due diligence paid to any new drivers utilised. Last Question: Any good advice to give me? eg. I've read here that it might be a good idea to lift the Xover point to the MF500 midrange from 500 hz to 600. etc.
I know this is a hazy concept but what I want to do is improve on the good points of the 66's and reduce the bad points without moving too far away from the Celestion sound.
Please note that I'm getting "professionals" to do the work.
Anyway, whatever advice you can provide will be gratefully accepted.
Reg
Hello to all those involved in this thread. It's been a lengthy read and I must confess to being overwhelmed by the technical aspects you have covered. I have no expertise to bring to the discussion, but I did want to thank you for reaffirming my faith in the Celestion 66's. I bought mine new in 1975 (for anyone interested, I paid $900 Australian). I had recently thought of selling them but when I had listened to a few other loudspeakers (up to $Aus 7000) I found that the 66's, for all their perceived faults, sounded like a true full-range speaker (and, depending on related equipment and a good recording, had touches of excellence). So I've decided to keep them and spend what I have to on their restoration. Hence my participation in this discussion. I have several questions that I hope someone will be kind enough to answer for me please. My 66's are series 1 'blackies'. More than a few years ago one of the original tweeters ceased functioning. Having no idea about anything I took the speakers to a repairer who replaced the tweeters with (what I have recently discovered to be) a no name brand. He also saw fit to bi-wire, reconfigure the Xover and update (some of) the capacitors. This is my first question: I understand, from reading this thread, that the original tweeters were not the best but replacing them would (probably) give rise to alterations to the Xover. However, given that this decision has already been taken out of my hands I'm now thinking of replacing the 'no-name's with Hickafon's (Hiquphon) OW1 or OW11. Is this a good idea? Second question: I have read previous advice contained in this thread about the 66 bass, ie. move the speakers away from walls/lift of the floor/block up the abr if it's annoying. However, I'm wondering if the Celestion woofers are worthy of being restored or are there better items now available? Third question: I've read, both here and on other internet forums, how good the MD500 midrange is. But because my 66's are the earlier series 1 they use the MF500. So, apart from the power rating, how do they rate vis a vis the MD500's? And again, like the woofer, are they a worthy item for restoration? Fourth question: Celestion sent me the original diagrams for the series 1 Xover's (also the series 11 and a pink noise test and some 66 publicity ads and reviews). Is it a good idea to have the Xovers rebuilt to original specifications but using upmarket (probably Hovland and Mundorf) capacitors and inductors and with due diligence paid to any new drivers utilised. Last Question: Any good advice to give me? eg. I've read here that it might be a good idea to lift the Xover point to the MF500 midrange from 500 hz to 600. etc.
I know this is a hazy concept but what I want to do is improve on the good points of the 66's and reduce the bad points without moving too far away from the Celestion sound.
Please note that I'm getting "professionals" to do the work.
Anyway, whatever advice you can provide will be gratefully accepted.
Reg
Thanks TVR. I never got to hear the 44's. When I purchased the 66's it was either them or the KEF Concerto's. The (relatively) small population of Australia doesn't support a huge range of retailers carrying a huge range of stock so we get what we get. Yes, you're probably right, there has been progress made but so have the prices. For example, I understand a pair of Wilson Benesch Square 2's are around 1000 pounds in Britain. Here they're Aus$6700. Anyway, I'll persevere. Cheers. Reg
possibly the amplifier or source electronics
DM, it is very good that your woofer is OK, because a replacement is hard to find and expensive for a good quality one now,
but before you pull everything apart:-
It is possible the fault is in one of the components or a connection in the crossover,
but from the description of the sound I think it is more likely in the amplifier in one channel.
I have heard similar from amplifiers.
(1)- connect a different loudspeaker to the amplifier and listen.
Any cone driver that is not less than 4ohm specified will be OK for this test, including an old television speaker or car-audio speaker,
and it does not have to be in an enclosure - sit it facing up and connect wires from it's terminals to the amplifier, play music and listen for the fault-sound.
(2)- if you do not have a different loudspeaker, then disconnect the crossover from the cabinet input terminals, and connect the woofer directly to the cabinet input terminals.
Connect ONLY the woofer - nothing else - no crossover.
Woofers can safely receive full bandwidth audio signals, though you will not hear much of the treble.
Be ready to Mute the sound quickly if the fault-noise appears, because it may be louder when no crossover, -{though not necessarily so}.
(3)- if you hear the fault-sound, then next - swap around the signal-source's Left and Right channels' leads into the amplifier, and listen again, because it has to be determined where the fault is coming from.
I'll explain later why an amplifier fault or amplified signal source fault can sound as if only coming from a woofer.
If no fault-sound from either channel of the amplifier or from a signal source component's channel -
{CD player or Radio or RIAA Preamp after Turntable's cartridge},
then Post here and I will describe how to simply test each component in the crossover.
****************************************************************
Hello everyone else !
Sorry, I have no more available time today.
I think I will have time to address your posts tomorrow.
DM, it is very good that your woofer is OK, because a replacement is hard to find and expensive for a good quality one now,
but before you pull everything apart:-
It is possible the fault is in one of the components or a connection in the crossover,
but from the description of the sound I think it is more likely in the amplifier in one channel.
I have heard similar from amplifiers.
(1)- connect a different loudspeaker to the amplifier and listen.
Any cone driver that is not less than 4ohm specified will be OK for this test, including an old television speaker or car-audio speaker,
and it does not have to be in an enclosure - sit it facing up and connect wires from it's terminals to the amplifier, play music and listen for the fault-sound.
(2)- if you do not have a different loudspeaker, then disconnect the crossover from the cabinet input terminals, and connect the woofer directly to the cabinet input terminals.
Connect ONLY the woofer - nothing else - no crossover.
Woofers can safely receive full bandwidth audio signals, though you will not hear much of the treble.
Be ready to Mute the sound quickly if the fault-noise appears, because it may be louder when no crossover, -{though not necessarily so}.
(3)- if you hear the fault-sound, then next - swap around the signal-source's Left and Right channels' leads into the amplifier, and listen again, because it has to be determined where the fault is coming from.
I'll explain later why an amplifier fault or amplified signal source fault can sound as if only coming from a woofer.
If no fault-sound from either channel of the amplifier or from a signal source component's channel -
{CD player or Radio or RIAA Preamp after Turntable's cartridge},
then Post here and I will describe how to simply test each component in the crossover.
****************************************************************
Hello everyone else !
Sorry, I have no more available time today.
I think I will have time to address your posts tomorrow.
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- Status
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