Hello all, i need some help from expert people about croossover design.
I have some normal hifi speakers model jbl l830. They are monitors/bookshelf.
Since i m in lockdown at home because i m positive to covid and i have some sb acoustics drivers around for serveral months (plan to build a good speaker) i start to look at jbl croossover and to my understanding i tried to swap the original jbl tweeter for my sb acoustics satori tw29rn-b-4. I got a mdf base for the sbacoustics tweeter and put it on top.It sounds ok and i like the sound but i see jbl tweeter are only 3.3 ohm.
I attached the jbl schematic. I appreciate if someone with experience could look at it and see if the satori is working ok with that type of croossover or if is needed to change some values. I have some resistors laying around and also some caps and coils. I m using the orginal croossover but with better parts, better caps and a better coil in woofer.
Thks[emoji846]
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I have some normal hifi speakers model jbl l830. They are monitors/bookshelf.
Since i m in lockdown at home because i m positive to covid and i have some sb acoustics drivers around for serveral months (plan to build a good speaker) i start to look at jbl croossover and to my understanding i tried to swap the original jbl tweeter for my sb acoustics satori tw29rn-b-4. I got a mdf base for the sbacoustics tweeter and put it on top.It sounds ok and i like the sound but i see jbl tweeter are only 3.3 ohm.
I attached the jbl schematic. I appreciate if someone with experience could look at it and see if the satori is working ok with that type of croossover or if is needed to change some values. I have some resistors laying around and also some caps and coils. I m using the orginal croossover but with better parts, better caps and a better coil in woofer.
Thks[emoji846]
View attachment 918329
View attachment 918330View attachment 918331
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Not clear to me if the SB replaces the HF tweeter or the UHF supertweeter.
You should run a sim to see how it works.
Software | Visaton
Import a similar project into the projekte folder and set it up the JBL way:
3 Wege – Boxsim Projektdatenbank
This might be quite close:
Lotte – Boxsim Projektdatenbank
I don't think your current impedance will be bad with those resistors bumping it up. But generally you make tweeter capacitors bigger and shunt coils smaller with 4 ohm tweeters. Say 5,6uF and 0.15 mH on the tweeter.
It's also quite common to put, say a 2.7R resistor in series with a low impedance tweeter after the filter to make it behave like a higher impedance one. The DC resistance measurement can help here. Usually 6 ohms with an 8 ohm nominal driver.
You should run a sim to see how it works.
Software | Visaton
Import a similar project into the projekte folder and set it up the JBL way:
3 Wege – Boxsim Projektdatenbank
This might be quite close:
Lotte – Boxsim Projektdatenbank
I don't think your current impedance will be bad with those resistors bumping it up. But generally you make tweeter capacitors bigger and shunt coils smaller with 4 ohm tweeters. Say 5,6uF and 0.15 mH on the tweeter.
It's also quite common to put, say a 2.7R resistor in series with a low impedance tweeter after the filter to make it behave like a higher impedance one. The DC resistance measurement can help here. Usually 6 ohms with an 8 ohm nominal driver.
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Mucking about with an inappropriate crossover won't get you very far;
take the trouble to learn what's actually required:
Passive Crossover Network Design
take the trouble to learn what's actually required:
Passive Crossover Network Design
Life is too short to achieve Mastery in the Ancient Art of Crossovery for most people. We want to get there FAST! 😎
I ran your JBL up the flagpole in a very loose way to see what it does.
First observation is waveguide tweeters are very different animals from dome tweeters:
H1499-06 27TBCD/GB-DXT
H1147-06 27TBC/G
It was all bad news for a simple tweeter swap. 🙁
Nothing will blow up swapping tweeters, but the sound goes all over the place. The supertweeter circuit is dreadful too. Clearly they gave the new young graduate a cheap project to cut his teeth on. That 0.4mH in the supertweeter circuit is plain wrong. Should be much smaller. 😀
I would save that SB Satori tweeter for a better prospect. Few projects here: SB Acoustics & Satori Brand Archives - Madisound Speaker PDF Library
You might have fun building an 8" plus 1" speaker with this woofer:
8″ SB20PFCR30-8 / Paper – Sbacoustics
Crossover won't be hard.
I ran your JBL up the flagpole in a very loose way to see what it does.
First observation is waveguide tweeters are very different animals from dome tweeters:
H1499-06 27TBCD/GB-DXT
H1147-06 27TBC/G
It was all bad news for a simple tweeter swap. 🙁
Nothing will blow up swapping tweeters, but the sound goes all over the place. The supertweeter circuit is dreadful too. Clearly they gave the new young graduate a cheap project to cut his teeth on. That 0.4mH in the supertweeter circuit is plain wrong. Should be much smaller. 😀
I would save that SB Satori tweeter for a better prospect. Few projects here: SB Acoustics & Satori Brand Archives - Madisound Speaker PDF Library
You might have fun building an 8" plus 1" speaker with this woofer:
8″ SB20PFCR30-8 / Paper – Sbacoustics
Crossover won't be hard.
Attachments
That is a very wrong way to achieve anything meaningful. Forget the swapping tweeters in a crossover designed for another tweeter.
Look for DIY loudspeaker projects with exactly the same tweeter, for example:
SBA MW19P-8 Studio Monitor - Jantzen-audio.com
SBA 941 - 3-Way Classic - Jantzen-audio.com
You are plain wrong.
The supertweeter circuit is OK, the 0.4 mH inductor is spot-on.
The same tweeter/supertweeter combination from L830 also is used in larger models L880 and L890.
L880 measured frequency response (from Stereophile):
JBL Studio L880 loudspeaker Measurements | Stereophile.com
L880 measured frequency response (from SoundStage):
SoundStage! Measurements - JBL L890 Loudspeakers (6/2006)
Excellent tweeter-supertweeter integration. Elevated highs, though.
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Thanks for the help.
I will build a new speaker from scratch.
I have the drivers for the last 2 projects 2 way and 3 way but the crossovers are expensive and they sell them as a kit.
I think i will start as a two way.
I will build a new speaker from scratch.
I have the drivers for the last 2 projects 2 way and 3 way but the crossovers are expensive and they sell them as a kit.
I think i will start as a two way.
on your schematic i see you put 8 ohm drivers.. is that ok?
i think the are 4 ohm..or i´m wrong?
that projects look good but the crossover a expensive and i would like to have something cheaper.
the tweeter on the 2 ways is the 8ohm version.
for example i found this kit
Satorique - Lautsprecher - Satorique1 - Ringdome + Beryllium
but they only sell it with the drivers included.
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There was no way I could know that your JBL is 4 ohm drivers. You didn't tell me!
Nevertheless, my comments about the supertweeter circuit stand. A rotten design. 😀
The ratio of capacitance to inductance determines the impedance of the circuit.
Here dipping unnecessarily low at 8kHz. A schoolboy error that even Sonce should have picked up. 😱
What happens next is you get thrown a lot of suggestions. But without a crossover idea you are lost. 😕
What I moght do in your situation is build an MTM.
Should be affordable. And certainly very nice. Adapting this sort of crossover is easy enough. You could proabably use any SB 5" drivers you fancy if well behaved. I will help you, if you are interested.
Nevertheless, my comments about the supertweeter circuit stand. A rotten design. 😀
The ratio of capacitance to inductance determines the impedance of the circuit.
Here dipping unnecessarily low at 8kHz. A schoolboy error that even Sonce should have picked up. 😱
What happens next is you get thrown a lot of suggestions. But without a crossover idea you are lost. 😕
What I moght do in your situation is build an MTM.
Should be affordable. And certainly very nice. Adapting this sort of crossover is easy enough. You could proabably use any SB 5" drivers you fancy if well behaved. I will help you, if you are interested.
Attachments
Hello thanks for the help.I allready disconnect the sb acoustics tweeter. I don t understand much of the things you said about capacitance and indutance. But i know the very basic concepts of passive croossover 1 order and second order more or less.
I like your MtM sugestion but when i look to croossover a see so many parts..
Is possible to build MtM with less parts?? and lower value parts?
What drivers should i pick up?
I already download the visaton sim but i dont know where to start.
If you help me i will build a nice speaker.
Also i have this MW19P-8 woofer. But i can buy 5 inch woofers and build MTM if they are good and afordable, the same apllies to the tweeter.
I think there is a reasonably good loudspeaker lurking in there!
SB Acoustics Satori MW19P-8 Midwoofer
Your woofer has a bit of nasty breakup lurking at 5-6 kHz. We ought to crossover much lower than that.
Therefore I am thinking 2kHz positive polarity.
What we are trying to do is apply some mathematics:
Main issue for you is the box, which looks like reflex 20-30L. Can you build it or buy something second-hand which is adaptable? 😀
We might get away with something fairly simple, albeit adapted to 4 ohm tweeter with bigger capacitor and smaller coil :
But you don't know till you try it.
SB Acoustics Satori MW19P-8 Midwoofer
Your woofer has a bit of nasty breakup lurking at 5-6 kHz. We ought to crossover much lower than that.
Therefore I am thinking 2kHz positive polarity.
What we are trying to do is apply some mathematics:
Main issue for you is the box, which looks like reflex 20-30L. Can you build it or buy something second-hand which is adaptable? 😀
We might get away with something fairly simple, albeit adapted to 4 ohm tweeter with bigger capacitor and smaller coil :
But you don't know till you try it.
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How on Earth can it be a rotten design, when the transition between tweeter and supertweeter is perfect?! See yourself:
Even a schoolboy will not make an error you are constantly making - to use a completely different tweeters (Visaton) with the crossover designed for JBL (or other) tweeters.
My opinion is: supertweeters are a pure marketing trick and are not required with any competent tweeter.
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My learned friend, Sonce. As your experienced Engineering Supervisor, the subject under discussion is this Satori Woofer and this Satori tweeter.
SB Acoustics Satori MW19P-8 Midwoofer
TW29RN-B 4 ohm Black SATORI Tweeter by SB ACOUSTICS
How to knock that into shape? 😕
All that matters. We have given up on the JBL. Obviously unsatisfactory. 😀
SB Acoustics Satori MW19P-8 Midwoofer
TW29RN-B 4 ohm Black SATORI Tweeter by SB ACOUSTICS
How to knock that into shape? 😕
All that matters. We have given up on the JBL. Obviously unsatisfactory. 😀
No, the subject under discussion is whether JBL L830 crossover can be used (eventually with some modification) for that particular Satori tweeter:
But it can be modified only if there are measurements of Satori tweeter, which you did not have! It is very wrong to try to design crossover without measurements of exactly that Satori tweeter - it is the mistake you are continually making: trying to design crossover for other drivers, using measurements of Visaton drivers. It is wrong!
Because of that mistake, you are making another mistake, proclaiming JBL crossover faulty:
The correct answer is: No, that crossover can not be used, unless heavily modified.
But it can be modified only if there are measurements of Satori tweeter, which you did not have! It is very wrong to try to design crossover without measurements of exactly that Satori tweeter - it is the mistake you are continually making: trying to design crossover for other drivers, using measurements of Visaton drivers. It is wrong!
Because of that mistake, you are making another mistake, proclaiming JBL crossover faulty:
On the contrary, the JBL supertweeter circuit is good, as can be seen on measurements (post # 13)
Yes i can build a box, i have tools and have no problems with that.
Regarding the croossover i like the simplicity and low values, so if it could work like that i will do it. I just understand that if the tweeter was 8 ohms i will get away with lower values...
Regarding the first grafh, it says "2 way 4°order" that is a more complex filter correct? Can you explain? It is a more radical cut between the 2 drivers?
Having slept on it, I think your SB project is doable.
Mr. Troels Gravesen is being a bit secretive with detail, but he got this to work:
MW19P-8
All a bit experimental. But I incline to this sort of crossover with a bit of fiddling for a loud 4 ohm tweeter:
Ought to do something right. Bit undecided if a LC tank-notch across the bass coil might help here. Some severe breakup on the woofer.
Mr. Troels Gravesen is being a bit secretive with detail, but he got this to work:
MW19P-8
All a bit experimental. But I incline to this sort of crossover with a bit of fiddling for a loud 4 ohm tweeter:
Ought to do something right. Bit undecided if a LC tank-notch across the bass coil might help here. Some severe breakup on the woofer.
Looks like 24L and about 6"x2" or 150mm x 50mm reflex to me. 26cm wide.
MW19P-8
I don't suppose the stepped baffle is all that big a deal. Flat baffle would probably work.
I was trying to annoy Mr. Gravesen by deconstructing his crossover:
https://www.madisound.com/library/stacks/SB17NRXC35-8-and-SB29RDC-C000-4.pdf
Not an immediate issue, because the woodwork comes first. But that Madisound design seems to do the right things. SB Acoustics SB17NRXC35-8 Midwoofer
It has an LCR woofer notch, but we might simplify it. Still a bit of a beast to build. How it is.
MW19P-8
I don't suppose the stepped baffle is all that big a deal. Flat baffle would probably work.
I was trying to annoy Mr. Gravesen by deconstructing his crossover:
https://www.madisound.com/library/stacks/SB17NRXC35-8-and-SB29RDC-C000-4.pdf
Not an immediate issue, because the woodwork comes first. But that Madisound design seems to do the right things. SB Acoustics SB17NRXC35-8 Midwoofer
It has an LCR woofer notch, but we might simplify it. Still a bit of a beast to build. How it is.
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