It can be useful to measure the old one, then the new one. Do this straight away without moving the mic or anything else. Once you have this comparative information you can simulate the two simultaneously and adjust the crossover, the level padding and account for any tilt or resonances.
Please bear with me with this one 😬!
My Jamo 7.6 speakers which I have had the pleasure of owning since new and are now 22 year plus old in near mint condition.
These being same as Jamo D570 and similar to others inc 7.7 and D590.
Crossovers look identical to D570 and D590 but slightly diff to other Jamo models with the twin bass units in.
I have sympathetically upgraded the crossover capacitors with like for like uf mainly Clarity Caps ESA and also R1 inline tweeter resistor with Mundorf MREC10-2.2: 2R2 Mundorf M-Resist 10W Classic Resistor (2.2R). These were done approx 2 years ago and all good.
However over time and with the age of these speakers now this week I decided to change the tweeter units (as I think ferro fluid has dried out in these over time) to Scanspeak D2905/950000 Tweeter - Classic Range × 2 (being recommended ). These were a perfect fit as you can see above in my previous post.
These sound very nice compared to the original however they are 6 ohm tweets and I wasn't sure what the original ones were (but original Jamo 38819 tested 6.2 ohms Dc) as not stamped on tweet.
The sound at present is confusing me slightly as I am wondering if the new tweets @ 6ohm have changed or moved my crossover point as it seems I now have lots more Bass and mids also sound different (can't really explain).
Would appreciate a little guidance if possible. I am able to change capacitor values and or resistors in my crossover but I don't have any test equipment other than a capacitor tester and small handheld ohm resistance tester.
My thought are maybe I should change resistor value ( currently 2.2 ohms )and or capacitor uf on tweeter side as replacement tweets now 6 Ohms but I'm not sure and your thoughts would be very much appreciated .Find attached schematic of my crossover.
thank you all look forward to your thoughts.
Regards Adi
My Jamo 7.6 speakers which I have had the pleasure of owning since new and are now 22 year plus old in near mint condition.
These being same as Jamo D570 and similar to others inc 7.7 and D590.
Crossovers look identical to D570 and D590 but slightly diff to other Jamo models with the twin bass units in.
I have sympathetically upgraded the crossover capacitors with like for like uf mainly Clarity Caps ESA and also R1 inline tweeter resistor with Mundorf MREC10-2.2: 2R2 Mundorf M-Resist 10W Classic Resistor (2.2R). These were done approx 2 years ago and all good.
However over time and with the age of these speakers now this week I decided to change the tweeter units (as I think ferro fluid has dried out in these over time) to Scanspeak D2905/950000 Tweeter - Classic Range × 2 (being recommended ). These were a perfect fit as you can see above in my previous post.
These sound very nice compared to the original however they are 6 ohm tweets and I wasn't sure what the original ones were (but original Jamo 38819 tested 6.2 ohms Dc) as not stamped on tweet.
The sound at present is confusing me slightly as I am wondering if the new tweets @ 6ohm have changed or moved my crossover point as it seems I now have lots more Bass and mids also sound different (can't really explain).
Would appreciate a little guidance if possible. I am able to change capacitor values and or resistors in my crossover but I don't have any test equipment other than a capacitor tester and small handheld ohm resistance tester.
My thought are maybe I should change resistor value ( currently 2.2 ohms )and or capacitor uf on tweeter side as replacement tweets now 6 Ohms but I'm not sure and your thoughts would be very much appreciated .Find attached schematic of my crossover.
thank you all look forward to your thoughts.
Regards Adi
Attachments
Thank you Allen for your thoughts. Will give it a go tomorrow . My only concern is will removing the 2.2 ohm resistor @ R1 on the tweeter affect the overall resistance of the speakers and drop , as I believe these Jamos can drop at certain frequencies to around 2 ohms overall . Many thanks.
Good morning AllenB .
I have removed the 2.2ohm resisters and replaced with cable. Much much better but way too bright. I’m a bit stuck now with choice of replacement resister as it obviously needs something in there 😵💫 any thought on value would be much appreciated .. any thoughts on poss a 1 ohm or should I go lower or higher .apologise for being a pain.
I have removed the 2.2ohm resisters and replaced with cable. Much much better but way too bright. I’m a bit stuck now with choice of replacement resister as it obviously needs something in there 😵💫 any thought on value would be much appreciated .. any thoughts on poss a 1 ohm or should I go lower or higher .apologise for being a pain.
What I usually (would) do is not remove the 2.2, just put the cable across it. Then, I'd try other resistors across it. Try another 2.2 = 1.1 total.. if not, try again larger or smaller.
It's OK that you've removed it now. I can't suggest a value, you have to do that. Maybe 1 ohm, 0.5 ohm..?
It's OK that you've removed it now. I can't suggest a value, you have to do that. Maybe 1 ohm, 0.5 ohm..?
Hi all.
Just thought I,d give a quick update to the replacement tweets to Scanspeak D2905/950000 Tweeter in my Jamo 7.6 . After a week or so the tweet has opened up nicely, very airy nice soft but clear sound now I have settled on a pair of 1.5ohm mills MRA12 resistors for the tweets. This could however be dropped IMO to somewhere in the region of 1 to 1.2 ohms if you prefer more tweet detail, however I prefer personally at 1.5ohms.
Many thanks to AllenB for your help.
Just thought I,d give a quick update to the replacement tweets to Scanspeak D2905/950000 Tweeter in my Jamo 7.6 . After a week or so the tweet has opened up nicely, very airy nice soft but clear sound now I have settled on a pair of 1.5ohm mills MRA12 resistors for the tweets. This could however be dropped IMO to somewhere in the region of 1 to 1.2 ohms if you prefer more tweet detail, however I prefer personally at 1.5ohms.
Many thanks to AllenB for your help.
So glad people enjoy music/hifi/diy, and that this thread live and help people, thanks AllenB 🙂
Listening now again for 2 day´s at the modified Jamo d590, and they are sooo good!
Sounds like a 30 times more expensive speaker..And that´s.incredibly!
And again i must go and feel on other drivers if only the 8 inch Peerlees is playing because of the superb bass in the room.
best regards John
Listening now again for 2 day´s at the modified Jamo d590, and they are sooo good!
Sounds like a 30 times more expensive speaker..And that´s.incredibly!
And again i must go and feel on other drivers if only the 8 inch Peerlees is playing because of the superb bass in the room.
best regards John
Hello.
I would like to ask for help.
If I only want to replace the speakers without any internal changes, I would also only want to replace the lower subwoofer, what would be the appropriate speaker? So that I don't have to touch anything else, just a quick subwoofer replacement.And I would also like to ask how many ohms the original speakers are? And what are their exact dimensions?
I looked into this: https://www.soundimports.eu/en/sb-acoustics-sb23mfcl45-8.html
Thank you in advance for your answer
I would like to ask for help.
If I only want to replace the speakers without any internal changes, I would also only want to replace the lower subwoofer, what would be the appropriate speaker? So that I don't have to touch anything else, just a quick subwoofer replacement.And I would also like to ask how many ohms the original speakers are? And what are their exact dimensions?
I looked into this: https://www.soundimports.eu/en/sb-acoustics-sb23mfcl45-8.html
Thank you in advance for your answer
In the first post Jawen used the following;
Peerless SLS 830667 (8Ohm) for woofer
Peerless by Tymphany SLS-P830667 - 8" Subwoofer
Now you are looking at a nice SBAcoustics subwoofer and would like some help. Your good question may take a little bit of time to resolve thoroughly.
They are both nominal 8 ohm drivers. As I am not familiar with the internals of the design and how large the compartment for the bass driver is you need to figure that out or find the manufacturers specification sheet or something that details its size in litres. I do not know if the Peerless was a drop in replacement for the original, or if it needed a little work.
you will need to understand the mounting dimensions of the original driver, and ideally verify that your driver fits or will need a larger cut-out, or a new fitment plate if smaller. Additionally, the SBAcoustics driver seems to have a far larger(taller) magnet assembly, will it in fact fit into the original compartment depth wise without hitting a panel.
Once you have verified it will fit nicely, you will need to use some software to simulate does it behave in a similar manner to the original, or Peerless. I am sure people will help with a software simulation if you can provide more data.
Peerless SLS 830667 (8Ohm) for woofer
Peerless by Tymphany SLS-P830667 - 8" Subwoofer
Now you are looking at a nice SBAcoustics subwoofer and would like some help. Your good question may take a little bit of time to resolve thoroughly.
They are both nominal 8 ohm drivers. As I am not familiar with the internals of the design and how large the compartment for the bass driver is you need to figure that out or find the manufacturers specification sheet or something that details its size in litres. I do not know if the Peerless was a drop in replacement for the original, or if it needed a little work.
you will need to understand the mounting dimensions of the original driver, and ideally verify that your driver fits or will need a larger cut-out, or a new fitment plate if smaller. Additionally, the SBAcoustics driver seems to have a far larger(taller) magnet assembly, will it in fact fit into the original compartment depth wise without hitting a panel.
Once you have verified it will fit nicely, you will need to use some software to simulate does it behave in a similar manner to the original, or Peerless. I am sure people will help with a software simulation if you can provide more data.
The sb23mfcl requires a much smaller cabinet than 48L or a very long vent (> 35 cm)
Here the peerless is available
https://www.soundimports.eu/en/peerless-by-tymphany-sls-p830667.html
Alternatives that should work quite good in 48L BR (you have to check if they fits well and the dimensions of the vent)
https://www.soundimports.eu/en/sb-acoustics-sb20pfcr30-8.html
Ideal should be like this (42L @37Hz). You can reduce the volume by putting brick or similar materials inside. The same can be done for the vent.
As shadowplay62 say, the 48 liter originalvolyme is a little big for the SB woofer, around 39 liter would be ideal.
This is how it look´s inside behind the woofer, after i unmounted original eggfoam-damping.
You have a flat surface that you easy can use inside, if you need to reduce the litervolyme for the SB woofer.
Just glue some MDF pieses on the flat surface inside.
Regards John
Attachments
Thank you very much for your help. Then theoretically https://www.soundimports.eu/en/peerless-by-tymphany-sls-p830667.html This speaker would be good without any drawbacks.And then I think I'll stick with this speaker, and this speaker should just be replaced. And that way, there shouldn't be any modifications to the speaker box or crossover.
Peerlees woofer are 2-3 mm wider than Jamo original woofer, and also different shape at the basket-endings.
You must fill up the mounting-hole with small pieces of 4 mm MDF. (cut so it fits and glued)
Try to show you with 2 pics, 1 where ju have to "fill-up", and 1 showing the difference at basket-ending.
Attachments
I understand. Okay and thank you for the answer. Then this might be the solution. But I would still like you to look at this speaker : https://www.soundimports.eu/en/seas-cd22rn4x.html , simulate it in a program to see if it would be good? If not, then the previous solution remains. I would be talking about this speaker: https://www.soundimports.eu/en/seas-cd22rn4x.html I would be curious to see what parameters come out. Thanks 😉👍