If you still ever hear a slight harsh/brash top-end sound,
you can simply put a 10 ohm resistor across the tweeters terminals.
This will give a subtle amount of 'taming'.
you can simply put a 10 ohm resistor across the tweeters terminals.
This will give a subtle amount of 'taming'.
Thanks ellnic ...... I will definitely do the bass push test when all the drivers are back in ....... seems a very simple and convenient way of testing for leaks. Still working on the second cabinet rebuild / mod so will be a little while before I get stuck into the Crossover. ...... will post a few pictures of the cabinets so far ..... every edge braced with 90 degree quad secured with nails and flexible silicon adhesives ..... then a layer of ply on all surfaces damped with silicon and then covered with acoustic felting ..... and then all covered in sound dampening foam .....and lastly real wool stuffing ...... hmmmm- nothing left to chance ! All time consuming but it keeps me off the streets !
Thanks Mister Audio ....... with a new tweeter installed I may have to do some adjustment, so very grateful for your recommendation.
Thank you chrisng and ellnic ........ the task has now got considerably easier with the above diagram ........ but for now, back to the cabinets.
Here are some pics of cabinet bracing and the drivers. What always amazes me is the "brand new " look of Goodmans drivers when the cabinet is opened for the first time in over 50 years. As you can see, the woofers and mids are very heavily constructed....... I have included a picture of the original tweeter and my replacement ScanSpeak Discovery D2608/9130 ( I am hoping for a good match as both drivers are around 90 to 91 db, both 8 Ohms, with the Scanspeak very flat between 3000 and 20,000 hz ). I will be mounting the new tweeter on the front as I will get a more secure hold - I didn't trust those tiny bolts into the chipboard baffle.
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@Mister Audio great tip on the resistor thanks 🙂
@chrisng thanks! 🙂
@mf4ever looking good. Those mids are pristine. Usually the adhesive holding the PVC surround starts to drift in over time causing rippling. I had to heat gun mine and pull it back to its correct position. Those alnico mids are superb drivers with a lot of range and feeling. In the 2 way mezzo (I think it was the mezzo) they just use that and the bass driver.
Nice work on the baffle, too. I haven’t done much to my Ks yet except the crossover, I’ll be interested to know what this all sounds like when it comes together.
This is highly subjective, but with one of the K2 pairs I have, I went down the route of gutting all wadding and removing the crossover then just using caps on the mids and tweets and mechanically doping the drivers with plastidip spray. It works surprisingly well.
@chrisng thanks! 🙂
@mf4ever looking good. Those mids are pristine. Usually the adhesive holding the PVC surround starts to drift in over time causing rippling. I had to heat gun mine and pull it back to its correct position. Those alnico mids are superb drivers with a lot of range and feeling. In the 2 way mezzo (I think it was the mezzo) they just use that and the bass driver.
Nice work on the baffle, too. I haven’t done much to my Ks yet except the crossover, I’ll be interested to know what this all sounds like when it comes together.
This is highly subjective, but with one of the K2 pairs I have, I went down the route of gutting all wadding and removing the crossover then just using caps on the mids and tweets and mechanically doping the drivers with plastidip spray. It works surprisingly well.
@mf4ever one thing I will say (you may have already thought of this) is that if you do front mount that scanspeak, you may need to add mounting strips of wood for the grille to sit on like the K2. Or if you are recovering them, cut the hole in the grille a bit bigger so that the front plate can protrude without touching it. Depends how you want the grille to look. Another option would be to ever so slightly drill out the scanspeak holes to facilitate slightly larger bolts if you don’t want the existing ones and return to rear mounting.
Hi ellnic.... Below is a picture of my Goodmans ........ totally original including the stands BUT since I am never going to sell them I feel I am not constrained by authenticity ....... so I'm thinking of refitting new grills with some crazily wild 1960s print ........ our house has every room in different wildly bright colours so the speakers will fit in just nice. ( some Goodmans fans may think this is desecration and I do understand that view as I have been a colonial cedar furniture restorer for over 40 years and absolutely insist that everything is totally original ....... but Audio should be fun )
I never had the guts to strip everything out and just dope the cones and have minimum caps ....... Dr Bunsen Honeydew in an extensive thread on HiFi Subjectivist went into great detail as to the process .......... he concluded that the results were amazing ...... but at the moment I am not that confident so I will stick to a rebuilt crossover with no L-pads ....... but who knows in the future.
Sorry ...... can't get the photo on ..... will try later
I never had the guts to strip everything out and just dope the cones and have minimum caps ....... Dr Bunsen Honeydew in an extensive thread on HiFi Subjectivist went into great detail as to the process .......... he concluded that the results were amazing ...... but at the moment I am not that confident so I will stick to a rebuilt crossover with no L-pads ....... but who knows in the future.
Sorry ...... can't get the photo on ..... will try later
It’s actually Doc’s threads on HFS that got me doing those mods. I have a thread over on HFS but I couldn’t use this username as the forum wouldn’t let me (too short I think) so my username is lysergic-skies. I’ve only done the mod on one set of speakers so far, but it does work well. I found the process to be much more forgiving than you’d think. Although before everything sets and cures fully (a few days) it does appear you’ve gone too far, then everything just comes back to life. I experimented with mixing and matching the drivers from the Ks and K2s but ended up with stock drivers for my K2 doped pair and just have a 4.7uF cap on the tweeter, 42uF on the mid and left the bass alone (it’s already doped and full range). The tweet and mid just have plastidip. I’ve recently experimented with the phase. I currently have the tweet and bass in phase with the mid out of phase. I’m going to try the tweeter out of phase too, which would be the same as original crossover. I dare say I’ll be adjusting and tinkering with cap values on the mid for some time to come. I totally understand why you don’t want to risk it at this point with yours. The only reason I did is because I ended up with 5 pairs of speakers - you do think “am I doing the right thing?” as you snip all the wires and spray the cones! Start with the rebuilt crossover and see how you feel about them.
Yeah I get what you mean about purists. But there are enough of these in pristine condition for it not to be a major deal. If they were one of a kind and belonged in a museum I would totally get it. Do what you want so they look good in your home. Some awesome psychedelic 60s print would suit them well! Pics when you’re done! ;-)
Yeah I get what you mean about purists. But there are enough of these in pristine condition for it not to be a major deal. If they were one of a kind and belonged in a museum I would totally get it. Do what you want so they look good in your home. Some awesome psychedelic 60s print would suit them well! Pics when you’re done! ;-)
For those who are interested, this is what the inside of the cab of one of the doc mods looks like:
Please excuse the over exposure, but the photo was dark.
You can see the 4.7uF poly cap for the tweeter on the right and on the left is a temporary electrolytic coupled with a poly totalling about 40uF. (This set of speakers is my 2nd set of K2s which I am experimenting on). The pristine pair have polys on both sides. I just didn’t have enough polys for the 2nd set so dropped an electrolytic in there with a poly to help the highs.
You may also notice…. The port! Yes I added a port. I found some of these of Canuck Audio Mart with ports added. Now before you scream NO! I hear ya… this was the whole point of not ruining the pristine pair. This pair were a wreck and I’ve slowly fixed them up, doc modded them, and I thought I would have a play.
So what is the result of the port? Well obviously, as expected, the bass isn’t as tight. However, it’s a lot better than I expected. The ports were donors from something off freecycle (can’t remember what). ID is small, about 35mm. Original port length was about 80mm but has been extended to about 180mm with a loo roll tube and pink duck tape ;-) these ones have a sacrificed old pillow in each to aid chuff reduction. To be really honest, I think they sound pretty damn good.
No really, I’m actually quite impressed. Whether or not the drivers will set fire to themselves and launch my house into space is another question, but there’s definitely a lot more depth and I fancy they image a bit better (not a strong point of these due to age, obviously). One thing I did have to due is attenuate the mid and highs to get the balance right. The jury is still out on this one. I am experimenting. Whereas the pristine ones without the ports have no attenuation.
Disclaimer: I’m not saying K2 owners should do this. I think they sound good, someone else with a more trained ears will probably say they sound like crap.
Here’s what the fronts look like:
I’ve completely blacked the drivers and replaced the screws with black hex bolts (yes there are some places that need touching up - where I’ve been removing and replacing drivers, some of the paint has flaked off). The veneer was an absolute s*** show. I’ve done my best but I won’t showcase that ;-) mid and tweets have been doped with plastidip. I risked the bass centre cap and found it wasn’t essential that it breathed so we’ve got an all black look 😎 I am not sure if the port is too small but it’s all I had an I figured the bass is so huge it probably wouldn’t need much. I tried to mimic the position of those I found, in the hope that it worked well 😛
Let the ripping apart [or compliments ;-)] commence!
Please excuse the over exposure, but the photo was dark.
You can see the 4.7uF poly cap for the tweeter on the right and on the left is a temporary electrolytic coupled with a poly totalling about 40uF. (This set of speakers is my 2nd set of K2s which I am experimenting on). The pristine pair have polys on both sides. I just didn’t have enough polys for the 2nd set so dropped an electrolytic in there with a poly to help the highs.
You may also notice…. The port! Yes I added a port. I found some of these of Canuck Audio Mart with ports added. Now before you scream NO! I hear ya… this was the whole point of not ruining the pristine pair. This pair were a wreck and I’ve slowly fixed them up, doc modded them, and I thought I would have a play.
So what is the result of the port? Well obviously, as expected, the bass isn’t as tight. However, it’s a lot better than I expected. The ports were donors from something off freecycle (can’t remember what). ID is small, about 35mm. Original port length was about 80mm but has been extended to about 180mm with a loo roll tube and pink duck tape ;-) these ones have a sacrificed old pillow in each to aid chuff reduction. To be really honest, I think they sound pretty damn good.
No really, I’m actually quite impressed. Whether or not the drivers will set fire to themselves and launch my house into space is another question, but there’s definitely a lot more depth and I fancy they image a bit better (not a strong point of these due to age, obviously). One thing I did have to due is attenuate the mid and highs to get the balance right. The jury is still out on this one. I am experimenting. Whereas the pristine ones without the ports have no attenuation.
Disclaimer: I’m not saying K2 owners should do this. I think they sound good, someone else with a more trained ears will probably say they sound like crap.
Here’s what the fronts look like:
I’ve completely blacked the drivers and replaced the screws with black hex bolts (yes there are some places that need touching up - where I’ve been removing and replacing drivers, some of the paint has flaked off). The veneer was an absolute s*** show. I’ve done my best but I won’t showcase that ;-) mid and tweets have been doped with plastidip. I risked the bass centre cap and found it wasn’t essential that it breathed so we’ve got an all black look 😎 I am not sure if the port is too small but it’s all I had an I figured the bass is so huge it probably wouldn’t need much. I tried to mimic the position of those I found, in the hope that it worked well 😛
Let the ripping apart [or compliments ;-)] commence!
Hi ellnic ........ it's been a while but I have completed my rebuild of my Goodmans Magnum K with the L PADS REMOVED. Sadly I obviously got something wrong when I translated the cross over schematic kindly provided by you and Chrisng ( see first post in this thread ) ........ there is no sound and when I did a continuity test with the multimeter it stayed at zero.
Posted below is a picture of my cross over as well as a drawing showing what I did ......... I would be so grateful for any advice by the community here as I have spent sooooooooo. much time on this project and I feel very close to completion.
Posted below is a picture of my cross over as well as a drawing showing what I did ......... I would be so grateful for any advice by the community here as I have spent sooooooooo. much time on this project and I feel very close to completion.
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Chrisng ...... you are a lifesaver......... will do this today ....... will report on the progress....... truly much appreciated .....
CHRISNG ...... YOU WERE TOTALLY CORRECT ...............AMAZING !!!!!!!!!!!! Just finished , plugged in and they are really beautiful .......... mids and bass really smooth, the brand new tweeter will need 100hours as do the new caps ........ but could not be more happy with the results ...
Chrisng ......Started this rebuild 15 months ago so I am so thankful for your fine tuning here ........ and a big shout out to the diyaudio Community. Will put the second speaker on the bench tomorrow and begin the rebuild. Will let everybody know the final summation after both speakers finished and burned in ....... Cheers
Chrisng ......Started this rebuild 15 months ago so I am so thankful for your fine tuning here ........ and a big shout out to the diyaudio Community. Will put the second speaker on the bench tomorrow and begin the rebuild. Will let everybody know the final summation after both speakers finished and burned in ....... Cheers