Hi Alan
I have the new crossovers as suggested in #741etc installed and have had the frequency response checked. There is a rise of 4dB from 500Hz to 800Hz and the it falls from 1.2kHz by 7dB (to -4dB) at 3.5kHz and then rises by 2dB from 4kHz to 8kHz and then rises again by another 2dB from 12kHz to 18kHz.
Removing the 2.2mH inductor in the mid section reduced the rise from 500Hz to 800Hz to 2dB but the response continued to fall from around 1.5kHz through to the same dip to -4dB at 3.5kHz. (In some ways similar to Wayne Swan's curve in #755)
Could you suggest some solution to this to flatten the curve by lowering the low mids and bring up the upper mids?
Thanks
Jim
I have the new crossovers as suggested in #741etc installed and have had the frequency response checked. There is a rise of 4dB from 500Hz to 800Hz and the it falls from 1.2kHz by 7dB (to -4dB) at 3.5kHz and then rises by 2dB from 4kHz to 8kHz and then rises again by another 2dB from 12kHz to 18kHz.
Removing the 2.2mH inductor in the mid section reduced the rise from 500Hz to 800Hz to 2dB but the response continued to fall from around 1.5kHz through to the same dip to -4dB at 3.5kHz. (In some ways similar to Wayne Swan's curve in #755)
Could you suggest some solution to this to flatten the curve by lowering the low mids and bring up the upper mids?
Thanks
Jim
Farfield & impedance after removing 82R from RH spkr
Continuing on from my last post (#799).
I took some farfield and impedance measurements of the 66’s both before and after I removed the 82 ohm resistor from across the midrange on the right hand speaker with the MD500.
As mentioned in my previous post the R speaker appeared louder than the L speaker with the 82R in the R speaker mids circuit and removing the 82R appeared to improve the overall balance between L&R speakers. However, I can’t really see why I observed this as the farfield results shown here don’t seem to provide a reason for it. Could it be because the farfields were taken with the speakers in the middle of a different room and well away from any furniture and the listening tests were done with the speakers in their normal room position? Could it be because the farfield results below 500Hz are more closely matched after the 82R was removed? Have I missed something? Alan where are you?
The first picture shows the before and after results for the right hand speaker for farfield and impedance.
The second picture compares the farfield results for both L and R speakers before the 82R was removed (top trace) and the farfield results for the L and R speakers after the 82R was removed from the R speaker (bottom trace).
Continuing on from my last post (#799).
I took some farfield and impedance measurements of the 66’s both before and after I removed the 82 ohm resistor from across the midrange on the right hand speaker with the MD500.
As mentioned in my previous post the R speaker appeared louder than the L speaker with the 82R in the R speaker mids circuit and removing the 82R appeared to improve the overall balance between L&R speakers. However, I can’t really see why I observed this as the farfield results shown here don’t seem to provide a reason for it. Could it be because the farfields were taken with the speakers in the middle of a different room and well away from any furniture and the listening tests were done with the speakers in their normal room position? Could it be because the farfield results below 500Hz are more closely matched after the 82R was removed? Have I missed something? Alan where are you?
The first picture shows the before and after results for the right hand speaker for farfield and impedance.
The second picture compares the farfield results for both L and R speakers before the 82R was removed (top trace) and the farfield results for the L and R speakers after the 82R was removed from the R speaker (bottom trace).
Hi Alan
I have posted the crossover layout and the frequency response, both with and without the 2.2mH coil in the mid section which shows a flatter response without the coil. I hope that this indicates the issues as currently laid out. Can you suggest a change to flatten the response (less lower mid and more upper mid).
Thanks
Jim
I have posted the crossover layout and the frequency response, both with and without the 2.2mH coil in the mid section which shows a flatter response without the coil. I hope that this indicates the issues as currently laid out. Can you suggest a change to flatten the response (less lower mid and more upper mid).
Thanks
Jim
Attachments
interim reply
Hi Jim,
reconnect the 2.2mH inductors in the mid-sections of your crossovers or the mid-domes will be damaged as result of their suspensions being overdriven at frequencies they were not designed to handle !
First Order electrical High-Pass -{the 24uF cap}- cannot protect mid-dome drivers from over-excursion.
I think there is a mistake in your microphone/SPL measurements.
Does what you HEAR from the speakers when playing music correlate with your SPL measurements ?
I will comment on possibilities when I have time available.
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Hi DennyG,
trust your hearing and not farfield SPL Plots !
I will explain this when I have time available.
In the interim, do nearfield SPL plots -{with sound absorptive under the cabinet lip - thicknesses of rolled up woollen socks will suffice}-
and Impedance plots for BOTH your HF2000s and Post here if you are able.
At least one of the HF2000s may need a resistor trick, or something, to balance its output with the other, and I suspect that one is a little low in Impedance.
P.S. I think you may have inadvertantly posted an error in your #799:
Midrange Circuit
Sonicap 24uF in series with 1.8R MRA5
Sonicap 4uF inseries with 2.7R MRA5
82R MRA12 in parallel with midrange MD500
Is it not 82R in parallel with midrange MF ?
*** *** *** ***
Hi Simon,
I think it is not a time period before one clears the Moderation, but after a specific number of Posts ... however I have forgotten.
Send a message to the moderators and ask, or simply post in some other Threads about things you are interested in and see what happens.
*** *** *** ***
Hi Doug,
if you are still reading here, Post and tell us what has become of your 66s, or you might be a candidate for a visit by a 666 !
*** *** *** ***
I have to go now, and no, it didn't get me ... yet !!
Hi Jim,
reconnect the 2.2mH inductors in the mid-sections of your crossovers or the mid-domes will be damaged as result of their suspensions being overdriven at frequencies they were not designed to handle !
First Order electrical High-Pass -{the 24uF cap}- cannot protect mid-dome drivers from over-excursion.
I think there is a mistake in your microphone/SPL measurements.
Does what you HEAR from the speakers when playing music correlate with your SPL measurements ?
I will comment on possibilities when I have time available.
*** *** *** ***
Hi DennyG,
trust your hearing and not farfield SPL Plots !
I will explain this when I have time available.
In the interim, do nearfield SPL plots -{with sound absorptive under the cabinet lip - thicknesses of rolled up woollen socks will suffice}-
and Impedance plots for BOTH your HF2000s and Post here if you are able.
At least one of the HF2000s may need a resistor trick, or something, to balance its output with the other, and I suspect that one is a little low in Impedance.
P.S. I think you may have inadvertantly posted an error in your #799:
Midrange Circuit
Sonicap 24uF in series with 1.8R MRA5
Sonicap 4uF inseries with 2.7R MRA5
82R MRA12 in parallel with midrange MD500
Is it not 82R in parallel with midrange MF ?
*** *** *** ***
Hi Simon,
I think it is not a time period before one clears the Moderation, but after a specific number of Posts ... however I have forgotten.
Send a message to the moderators and ask, or simply post in some other Threads about things you are interested in and see what happens.
*** *** *** ***
Hi Doug,
if you are still reading here, Post and tell us what has become of your 66s, or you might be a candidate for a visit by a 666 !
*** *** *** ***
I have to go now, and no, it didn't get me ... yet !!
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You are correct Alan. The MD500 has no // 82R. The corrected latest mods are:
Bass circuit (Solen caps were manufactured in about 1989)
Solen 68uF in series with 1.5R MRA5 (parallel to woofer)
(Solen 68uf // Solen 6uF) in series with 1.0R MRA5 (in other position)
Midrange Circuit
Sonicap 24uF in series with 1.8R MRA5
Sonicap 4uF inseries with 2.7R MRA5
82R MRA12 in parallel with midrange MF500 (not the MD500 as indicated in post #799)
Tweeter Circuit
Sonicap 4uf
Sonicap 6.2uF
HF2000 NearField and impedance
Hi Alan,
Here are the HF2000 Nearfield results with the drivers located on the 66 baffle. When I did these tests (during the Sonicap upgrade) I didn’t repeat them as I normally do so am unsure of the repeatability. Repeatability is normally pretty good but look at the second picture.
The next picture shows HF2000 Nearfield results with all drivers on the baffle and all drivers connected to the crossover and operating during the tests. I repeated the test for the R driver immediately after the initial test on that driver and the repeatability was not as good as I normally expect with my test setup. I can’t explain the 1 to 2 db difference for the R spkr for the two test runs.
Next picture shows the impedance of the HF2000 drivers. The DCR of the L spkr was 4.3 ohm and the R spkr was 5.2 ohm.
Hi Alan,
Here are the HF2000 Nearfield results with the drivers located on the 66 baffle. When I did these tests (during the Sonicap upgrade) I didn’t repeat them as I normally do so am unsure of the repeatability. Repeatability is normally pretty good but look at the second picture.
The next picture shows HF2000 Nearfield results with all drivers on the baffle and all drivers connected to the crossover and operating during the tests. I repeated the test for the R driver immediately after the initial test on that driver and the repeatability was not as good as I normally expect with my test setup. I can’t explain the 1 to 2 db difference for the R spkr for the two test runs.
Next picture shows the impedance of the HF2000 drivers. The DCR of the L spkr was 4.3 ohm and the R spkr was 5.2 ohm.
Hi Doug,
if you are still reading here, Post and tell us what has become of your 66s, or you might be a candidate for a visit by a 666 !
I have to go now, and no, it didn't get me ... yet !![/QUOTE]
The 66's went to Edmonton with both the seas & Hf 2000's. The fellow put them thru the paces ! Had some Asian music that had bass he said he had never heard any other spkr get to. & some single female vocal that must be way outside my upper response. He may or may not play with the xovers, dont know. I was just hoping they wouldnt explode during the testing.
($500 Canadian).
if you are still reading here, Post and tell us what has become of your 66s, or you might be a candidate for a visit by a 666 !
I have to go now, and no, it didn't get me ... yet !![/QUOTE]
The 66's went to Edmonton with both the seas & Hf 2000's. The fellow put them thru the paces ! Had some Asian music that had bass he said he had never heard any other spkr get to. & some single female vocal that must be way outside my upper response. He may or may not play with the xovers, dont know. I was just hoping they wouldnt explode during the testing.
($500 Canadian).
Denny, check one of the Plots ... and hello Doug !
Hi Denny,
in the first and second plots you have used Red for Left and Black/Blue for Right,
BUT in the the third plot - Impedance - you have swapped colours between Left and Right - is that correct or an inadvertant mistake ?
I ask because from BOTH the SPL plots it seems that the Left tweeter would have the higher Impedance.
If such is the case, then closer to matched output can be got, but if your Impedance plot ID is correct, then I'll have to think a bit about this ...
*** *** *** ***
Hi Doug,
I hope the buyer has clearly understood which output capacitor has to be used with which tweeter, because if he uses the 10uF cap with the HF2000 the HF2000 will be damaged if he drives the speakers hard,
and the SEAS will sound a bit removed from the midrange with the 6uF cap.
Also, the 27 ohm resistor should be used only with the SEAS tweeter, and not with the HF2000 or there will not be even sound through the crossover region.
So now are you speaker-less - what are you listening through ?
- or have you retired your ears now ...
Hi Denny,
in the first and second plots you have used Red for Left and Black/Blue for Right,
BUT in the the third plot - Impedance - you have swapped colours between Left and Right - is that correct or an inadvertant mistake ?
I ask because from BOTH the SPL plots it seems that the Left tweeter would have the higher Impedance.
If such is the case, then closer to matched output can be got, but if your Impedance plot ID is correct, then I'll have to think a bit about this ...
*** *** *** ***
Hi Doug,
I hope the buyer has clearly understood which output capacitor has to be used with which tweeter, because if he uses the 10uF cap with the HF2000 the HF2000 will be damaged if he drives the speakers hard,
and the SEAS will sound a bit removed from the midrange with the 6uF cap.
Also, the 27 ohm resistor should be used only with the SEAS tweeter, and not with the HF2000 or there will not be even sound through the crossover region.
So now are you speaker-less - what are you listening through ?
- or have you retired your ears now ...
Last edited:
Impedance plot is correct!
Hi Alan,
The plots are correct. I didn't notice the colour swap, it was the way the colours were assigned by the software as each data set was added.
I've tried out a different solid state integrated amp with the 66's and it has issues driving them. Sound is not quite right. Will go back to the old Suden for now.
DG
Hi Alan,
The plots are correct. I didn't notice the colour swap, it was the way the colours were assigned by the software as each data set was added.
I've tried out a different solid state integrated amp with the 66's and it has issues driving them. Sound is not quite right. Will go back to the old Suden for now.
DG
Thanks - particularly to Alan - for all the info on this thread. I have some Ditton 66s with dead tweeters so I'm planning on replacing them with Hiquphon OW1s. I'm organising a Group Buy for UK-ers for some OW1s and the price will work out to around £150 per pair. If you're interested, please see the thread on the Pink Fish forum in the DIY section - but be quick as it will only be open for a week or so!
hi people, sorry but i am new to this. o.k i have just got myself a pair of ditton 66's. just read a bit on here about recoating the mids. what material/solution/glue/paint did you use to do this please? also i have a pair of 44'''s but the cones are abit dull/dirty. some of the pictures on ebay shoe the drivers as quite shiney. sorry one more question, i think my tweeters in the 66's are from the series two. dose any one think this will be a problem? i love the sound of them very much i just wonderd if there could be any issues with the mk2 tweeter runnig of a mk1 crossover. thanks guys glad i got on here at last.
Disaster, the left mid dome on my 662s has started to resonate with a buzz at certain frequencies D:
Tomorrow I'll swap the left for the right to confirm the issue is with the dome and not the crossover (I doubt it, just seems worth checking), then I'll dissect it, consider the damage and type of failure and consider a possible fix.
I just doubt I'll manage to find a replacement part, these domes were only ever used in 662s :/
Any advice from those who've fixed 66 mids would be much appreciated.
Tomorrow I'll swap the left for the right to confirm the issue is with the dome and not the crossover (I doubt it, just seems worth checking), then I'll dissect it, consider the damage and type of failure and consider a possible fix.
I just doubt I'll manage to find a replacement part, these domes were only ever used in 662s :/
Any advice from those who've fixed 66 mids would be much appreciated.
Just finished poking around the thing, there was a dry joint that I fixed though that wasn't the issue and the foam insert sitting in the magnet cavity seemed to be protruding more than I thought it should so I poked it back in.
Neither of these things has fixed the issue, next I'm considering swapping the domes to make sure it's not a crossover issue.
Other than that I'm at a loss, the coil looked fine, it measures 7.6ohms reliably, I couldn't spot any mechanical issues in there.
Neither of these things has fixed the issue, next I'm considering swapping the domes to make sure it's not a crossover issue.
Other than that I'm at a loss, the coil looked fine, it measures 7.6ohms reliably, I couldn't spot any mechanical issues in there.
Flickr: maud_88's Photostream
Some pictures I took.
I fixed it, turns out the problem was the dome had somehow become misaligned, the key I found to setting it right again was to make sure that the wires coming from the dome were in their slots, hold the plate down roughly in position and them move it very small amounts into one can nudge the dome in and out ever so slightly without hearing it touch the edge of the circular slot it sits in. After finding that position simply screw the thing back up as tight as possible.
Some pictures I took.
I fixed it, turns out the problem was the dome had somehow become misaligned, the key I found to setting it right again was to make sure that the wires coming from the dome were in their slots, hold the plate down roughly in position and them move it very small amounts into one can nudge the dome in and out ever so slightly without hearing it touch the edge of the circular slot it sits in. After finding that position simply screw the thing back up as tight as possible.
Good DIY !
Hi SatinMill,
that has been a very good d.i.y. sequence !
Hopefully your photos will be of use to someone in the Forum,
though the two versions of the mid-dome used in Ditton 66 are quite different to this one from the 662.
There is mention of the 662 in another thread.
Search for:
Celstion 66 & 55 crossovers - question
{yes, Celestion is spelt incorrectly in the title of that thread}
started by:
lorienblack
It includes a diagram of its crossover and a few other comments,
but nothing about the mid-dome.
*** *** *** *** ***
Hi loves speakers,
both versions' tweeters are basically the same,
but do read through this thread about the capacitors in the crossover,
because if yours are the old black colour ones they could be leaking charge
and your tweeters may get damaged as result of lower frequencies bleeding through.
If yours are the green capacitors they will probably be OK.
*** *** *** *** ***
Hello everyone else.
I apologise, I am very busy and no time even for my own d.i.y. for a while.
I hope to be back here by the end of July to continue whatever yet to ...
Hi SatinMill,
that has been a very good d.i.y. sequence !
Hopefully your photos will be of use to someone in the Forum,
though the two versions of the mid-dome used in Ditton 66 are quite different to this one from the 662.
There is mention of the 662 in another thread.
Search for:
Celstion 66 & 55 crossovers - question
{yes, Celestion is spelt incorrectly in the title of that thread}
started by:
lorienblack
It includes a diagram of its crossover and a few other comments,
but nothing about the mid-dome.
*** *** *** *** ***
Hi loves speakers,
both versions' tweeters are basically the same,
but do read through this thread about the capacitors in the crossover,
because if yours are the old black colour ones they could be leaking charge
and your tweeters may get damaged as result of lower frequencies bleeding through.
If yours are the green capacitors they will probably be OK.
*** *** *** *** ***
Hello everyone else.
I apologise, I am very busy and no time even for my own d.i.y. for a while.
I hope to be back here by the end of July to continue whatever yet to ...
Last edited:
Thanks, I'd love to dissect a MD or MF dome, maybe I'll nab a broken one on ebay to see if I can revive it, they're both 8 ohms no? So I should be able to test any repair with my 662s right?
I believe the crossover frequencies are the same, 500Hz and 5KHz, just the bass is 8 ohms rather than 4.
I'm curious just how different the domes are, the tweeters are very similar to those on the 66, the coil winding is merely slightly lower down and more spread out and they generally seem slightly better built.
This is the second successful repair I've made, a while back I re-wound the coil on a HF2001 and again I'd love to try the same repair on a HF2000 it's just difficult to find faulty examples to work on.
I have three bad ones and I would be more than willing to send them to you if you could promise to fix one for me!
If you are interested please email me @ rock106_5@hotmail.com
Thanks Nick
Hello SatinMill , I also have 2 HF2001s that are down and out and would love to get them repaired or indeed do it myself . The SEAS 0737s which have replaced them in my 332s are OK but I feel they are missing something .
If you have a thread on this repair or could let us know your sequence and any issues I'm sure there's a few here would appreciate it .
Thank you.
If you have a thread on this repair or could let us know your sequence and any issues I'm sure there's a few here would appreciate it .
Thank you.
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