Thanks very much for your response.
BTW, I'm really new to diy.
Searching on Seas T25CF001 shows it is 6ohm, 91db, so I mentioned D25AG-35-06.
Is using alternative tweeters with this similar parameters (same norminal impedance and same sensitivity)enough? Or is there any parameter to look for on spec sheet?
Hello dear comrades! Tell me please if there are measurements of the frequency response after modifying the crossover at post #68 from Kimon? I have Jamo Concert 8, I'm thinking about replacing the crossover, which one is better to choose? According to the scheme that System7 provided in post # 62, there are measurements on graph. After these modifications, does the sensitivity or impedance of acoustics change?
I have not made any measurements after crossover modification (I lack both instruments and skills ), nor System7 did. I relied entirely on Boxsim's predictions and, I have to say, I think that they are very close to reality.
Anyway, you may Judge for yourself. You can load the W17E (woofer) and T25 ( tweeter) files (provided by Dissi) to the Boxsim and check the results for each crossover schematic. Have fun!
(It is true that impedance falls to a minimum of 3 ohm, according to Boxsim, with my schematic).
Anyway, you may Judge for yourself. You can load the W17E (woofer) and T25 ( tweeter) files (provided by Dissi) to the Boxsim and check the results for each crossover schematic. Have fun!
(It is true that impedance falls to a minimum of 3 ohm, according to Boxsim, with my schematic).
Hi all and thanks for this nice thread about this legendary's Concert 8 speakers.
I'm new to this forum and i have the opportunity to buy a pair but i like to inform me about possibles tweaks.
@kimon , your DIY crossover tweak make a substantial difference than the original but with High-End and same values components ?
Did you have made the test or directly tweak the crossovers ?
Can you give the right components you have buy to build your crossovers and how ?
Thanks for your reply and sorry for my english (i'm french)
Jérôme.
I'm new to this forum and i have the opportunity to buy a pair but i like to inform me about possibles tweaks.
@kimon , your DIY crossover tweak make a substantial difference than the original but with High-End and same values components ?
Did you have made the test or directly tweak the crossovers ?
Can you give the right components you have buy to build your crossovers and how ?
Thanks for your reply and sorry for my english (i'm french)
Jérôme.
Salut, Jerome. I just noticed your post, but it's late here and I am sleepy. I'll try to answer tomorrow.
Well, I used the existed pcb and re-used most of the parts of the old crossover. MKT capacitors are ok when in shunt ( in parallel with the speaker i.e. they are soldered between + and - ). Only in the high-pass I used a polypropylene tin foil cap. The value of each component is written on the shcematic (post #68). The 4.7 mH coil is a Visaton with a Part Number 3808. To build the 42 μF cap I soldered several smaller caps in parallel (from my spare box). Check the dimensions of each part before you order it, just to be sure it will fit in place.
Thanks for your reply and all the spec of all components.
Tomorrow will be the day to buy it...
Listen, i will drive more than 2000kms to buy not only Concert 8 but the limited edition 30th anniversary !
I will be back home on sunday but very late.
Pics to follow
PS : i know that this special Concert 8 version has a new filters than the original and maybe speakers too but i'm not sure and not really necessary to change the components but i think it will be a good reason to compare
Hello guys! I decided to make crossovers for my Concert 8 according to the System7 scheme. The characteristics of commercially available coils are slightly different. By the values of resistors and capacitors, everything seems to be OK?I'm not sure that works better, but it's your project. I got a hole in the midrange there, and a 0.25mH with a resistance of 1.3 must be rare as hen's teeth. Really, "if it's not broken, don't fix it" is the engineer's motto! Fixing the notch was the main event. The idea is to get the rolloff as straight a line as possible.
Original:
Mine:
You should post your frequency response if you want someone to check it.
Couple of Boxsim settings which matter. Boxsim needs to know the (minimal phase) frd measurement was made in "the box which is simmed". Acoustic centres (SEO) I guessed at 50mm for the bass and 17mm for tweeter. I used medium settings of 126 data points. I usually import over similar Visaton drivers to keep some factors similar. The AL170 and the SC10N here.
I did find my original sim was not very accurate due to some poor guesses. But I'm getting the same as Dissi now. And I think the phase is a bit butterworth, ie not precisely aligned.
Jantzen Air Core Coil 1,5mH AWG17 0,52Ohm, 000-1300
Jantzen Air Core Coil 0,25mH AWG18 0,25Ohm, 000-1904
Jantzen Air Core Coil 0,22mH AWG18 0,205Ohm, 000-1278
Resistor MOX Mundorf 10W 1.0 Ohm Metal Oxide
Resistor MOX Mundorf 5W 2.2 Ohm Metal Oxide
Resistor MOX Mundorf 5W 4.7 Ohm Metal Oxide
Resistor MOX Mundorf 5W 12 Ohm Metal Oxide
Capacitor MKP Mundorf MCap 250 VDC 2.2 uF
Capacitor MKP Mundorf MCap 250 VDC 4.7 uF
Capacitor MKP Mundorf MCap 250 VDC 6.8 uF
Capacitor MKP Mundorf MCap 250 VDC 10 uF
Hi guys,
As promised, I would like to present to you the very rare (1000 copies only) Concert 8 Limited Edition 30th Anniversary.
The sound is incredibly clear and the bass impressive for the size.
Glad to finally own them after all these years of waiting.
The installation is provisional, I will design custom feets for them this week.
More info to follow.
For infos, my amplifier is a Marantz PM7000 old version from 1999 with FX-Audio FX-01 DAC on PC with Foobar 2000 and FLAC & WAV files.
But i want to upgrade the amplifier with a new Leak Stereo 130 that include all entries i need and loose also some cables !
A good choice or not, that is the question but the many tests on youtube are convincing especially with the speakers used.
Some pics of this pure beauties
As promised, I would like to present to you the very rare (1000 copies only) Concert 8 Limited Edition 30th Anniversary.
The sound is incredibly clear and the bass impressive for the size.
Glad to finally own them after all these years of waiting.
The installation is provisional, I will design custom feets for them this week.
More info to follow.
For infos, my amplifier is a Marantz PM7000 old version from 1999 with FX-Audio FX-01 DAC on PC with Foobar 2000 and FLAC & WAV files.
But i want to upgrade the amplifier with a new Leak Stereo 130 that include all entries i need and loose also some cables !
A good choice or not, that is the question but the many tests on youtube are convincing especially with the speakers used.
Some pics of this pure beauties
Congratulations!Hi guys,
As promised, I would like to present to you the very rare (1000 copies only) Concert 8 Limited Edition 30th Anniversary.
The sound is incredibly clear and the bass impressive for the size.
Glad to finally own them after all these years of waiting.
The installation is provisional, I will design custom feets for them this week.
More info to follow.
For infos, my amplifier is a Marantz PM7000 old version from 1999 with FX-Audio FX-01 DAC on PC with Foobar 2000 and FLAC & WAV files.
But i want to upgrade the amplifier with a new Leak Stereo 130 that include all entries i need and loose also some cables !
A good choice or not, that is the question but the many tests on youtube are convincing especially with the speakers used.
Some pics of this pure beauties
View attachment 1027822
View attachment 1027826
View attachment 1027830
View attachment 1027833
kimon, I think I have come to some conclusions here.
This speaker is quite similar to the SEAS Thor:
Which is a BW3 MTM design by Joe D'Appolito which is sometimes criticised for light bass, IIRC.
This might just be a bass voicing problem, dependent on room size and placement. The SEAS Thor could be easily adjusted, IMO.
We have discovered the Jamo has a badly designed notch. That is fixed easily enough with two new components, 2.2R and 6.8uF. The voicing is adjusted for more bass with a 1.5mH coil for more slope and a 4.7R resistor to take tweeter down. 1R and 4,7uF doesn't do much, so we'll leave them. Finally, the T25 tweeter is bright at the top, so I like Joe's 12R/2.2uF zobel.
It all comes together as below. If you fix the notch and add the zobel, the voicing change can, of course, be tested on the biwireable connections externally with an additional 0.5mH and a 2.7R. The dotted line is your original as best we can sim it. Not too radical a change, really, and easily implemented I reckon..
I've just lashed up a mod to one speaker along the lines you've suggested, The only difference being that I found the effect of C1 R1 to be so minimal they have been omitted. With the values shown, I made an in-room measurement using averaged third-octive analysis and a pink noise source. Mic was on tweeter axis @ 800mm. There ara a couple of room modes to ignore (floor-ceiling) at 80 & 250Hz, but otherwise looks promising. The bass drive curve was taken with the loudspeaker in-situe in the cabinet.I found a third order tweeter was not so nice with fourth order bass. But don't let me stop you.
I use 8 ohms nominal as a conventional label. They are usually 6 ohms DC resistance and the sim knows this.
The dotted line in the original sim might show what the filter is doing in the original Jamo Concert 8:
Not pretty, is it? I would call that a flawed speaker.
The second redesign I came up with is carefully modelled based on Dave's frd. It's actually regular 4th order stuff, with an added 4kHz notch for the breakup and a 1.3kHz notch for the typical surround resonance. I'm not too sure about exact tweeter level, but it's adjustable anyway.
If it works, I think it'll sound good. I could have got the tweeter flatter, but it messed up the lovely impedance, and it will be fine off axis, IMO. But hey, it's all the hobby. And a hobby is, by definition, an interesting waste of time!
You can always get Boxsim from Visaton. I have a vague idea what I am doing when I import frd and zma files, but there's nothing like doing it yourself.
Attachments
For my 20 year old pair of Jamo Concert D 830 which I have in secondary system,
I am going to replace capacitors and resistors.
I am simply going to replace with same values is caps and resistors.
For replacement I got Solen SA (4.7 uf) , Mundorf M Supreme ( 6.8 and 10 uf) caps and Mills resistors.
I am going to replace capacitors and resistors.
I am simply going to replace with same values is caps and resistors.
For replacement I got Solen SA (4.7 uf) , Mundorf M Supreme ( 6.8 and 10 uf) caps and Mills resistors.
I believe a yellow capacitor marked as 106K 100V on the supplied crossover of Concert would mean value of 10.6 uf 100V. I am planning to replace this one with Mundorf M Supreme 10 uf 600V with Tolerance +/- 2 % , as I happen to have this one with me in spare . My question is : will be safe to install a 10.0 uf (+/- 2% ) value cap in place of 10.6 uf value cap? will it likely affect the out put noticeably or significantly?