Recently a friend with JBL L100s wanted me to make a PC board for crossover designed by Dennis Murphy:
http://www.diyaudio.com/forums/multi-way/182612-jbl-l100-restoration-upgrade.html
So I did a BOM and discovered prices for a completed crossover vary all over the place depending upon the grade of the parts used e.g. electrolytic vs polypropylene film caps, inductors, etc.
To make matters even more cloudy, China crossovers sold on eBay seem very promising, especially the attractive layouts and prices:
Speaker Crossover | eBay
3 Way Speaker Crossover | eBay
Can anyone share their experiences using China crossovers purchased on eBay?
http://www.diyaudio.com/forums/multi-way/182612-jbl-l100-restoration-upgrade.html
So I did a BOM and discovered prices for a completed crossover vary all over the place depending upon the grade of the parts used e.g. electrolytic vs polypropylene film caps, inductors, etc.
To make matters even more cloudy, China crossovers sold on eBay seem very promising, especially the attractive layouts and prices:
Speaker Crossover | eBay
3 Way Speaker Crossover | eBay
Can anyone share their experiences using China crossovers purchased on eBay?
Sorry Deltalight, but loudspeaker crossovers should be dedicated, that is, individual SPL en Z characteristics of the woofer and tweeter (and mids, if applicable) should be taken in taken into consideration in filter design.
Generic crossover are totally worthless.
Kind regards,
Eelco
Generic crossover are totally worthless.
Kind regards,
Eelco
Hi,
Off the shelf x/o's are cheap because they are mass
produced, but they are also very wrong in most cases.
They can be used for cheap parts if you know what you
are doing, but basically used for poor PA's and not hifi.
You can usually work out the parts values on the boards
from the spec and using very basic (wrong) x/o calculators.
The DM x/o is not simple and is not cheap. The original
JBL x/o is ultra simple and ultra cheap, and very poor.
New crossover design for L-100A
If your friend wants the DM x/o build it.
rgds, sreten.
Off the shelf x/o's are cheap because they are mass
produced, but they are also very wrong in most cases.
They can be used for cheap parts if you know what you
are doing, but basically used for poor PA's and not hifi.
You can usually work out the parts values on the boards
from the spec and using very basic (wrong) x/o calculators.
The DM x/o is not simple and is not cheap. The original
JBL x/o is ultra simple and ultra cheap, and very poor.
New crossover design for L-100A
If your friend wants the DM x/o build it.
rgds, sreten.
I never thought much of the off the shelf crossover. But your Ebay link changed my mind. I saw this 3-way, 2nd order crossover at $45 a pair.
2pcs Kasun as 33c 3 Way 3 Unit Hi Fi Speaker Frequency Divider Crossover Filters | eBay
It seems to be an exception that the seller (World Sky Electronics) posts the full schematics with detail component valves, response curves etc. Even the board and component look pretty decent. You cannot buy the parts at this cost in the US. Considering the fact that the JBL L-100 has practivally no crossover to speak of, this one could have been an improvement. For $45 a pair, you can afford to try it without much to lose.
No, I have had no experience with this seller or other off the shelf units from the Chinese sellers. I will be very interested in what you can find out.
There are some chinese sellers that really make and sell good stuff.
I've bought speaker foam/rubber from a couple, and LED's from another couple, and have really been impressed. They make good stuff and spec it right and deliver above what they promise.
I wont discard it just cos its chinese, they have been making electronic parts for decades. Even the high end caps and inductors come from china of late.
Cool.
Srinath.
I've bought speaker foam/rubber from a couple, and LED's from another couple, and have really been impressed. They make good stuff and spec it right and deliver above what they promise.
I wont discard it just cos its chinese, they have been making electronic parts for decades. Even the high end caps and inductors come from china of late.
Cool.
Srinath.
Why do you think that with this so called "crossover" a JBL L100 will have a better linearity and better phase integration than original simple first order crossover that JBL L100 already has? A crossover is not just a frequency divider. None of the speakers are linear, none of the speakers has a flat impedance and none of the speakers have the same phase response and none of the speakers have the same sensitivity. I would never change any of crossover components if I would not have a measurement microphone and not knowing what any of this component does, and not being confident what I do, even if this speaker has a simple first order crossover, but which is made by professionals. And I would never give an advises about speaker crossovers, not having understanding how a speaker crossover works.
As I can see this 2pcs Kasun as 33c 3 Way 3 Unit Hi Fi Speaker Frequency Divider Crossover Filters | eBay so called "crossover filter" have cheapest eletrolitic caps (not counting a pair of low qualitiy MKP), cheapest inductors and cheapest resistors one can buy. The frequency response curve in this link most probably is made using Adobe Photoshop.
"Why do you think that with this so called "crossover" a JBL L100 will have a better linearity and better phase integration than original simple first order crossover that JBL L100 already has?"
It won't.
This is not what he wants to hear, so what is the point into trying to talk some sense into him?
It won't.
This is not what he wants to hear, so what is the point into trying to talk some sense into him?
Hi,
Well it certainly isn't the measurements of that x/o.
The mid slopes are 24dB/octave, but there are are
simply not enough components in the mid section
to achieve the high slopes shown.
rgds, sreten.
I totally agree with you that "The original JBL x/o is ultra simple and ultra cheap, and very poor". It cannot even be called a "first order". JBL tricked people into believing that no crossover has "better linearity and better phase integration", which would only be true if the individual driver were perfect with the optimized roll-off points.
I am more of the British school of thinking on crossovers. The Brit believes that you need to use the crossover to tailor and compensate the driver inperfection. For mid price range speakers, I found that approach yield much better sound stages.
The Dennis Murphy crossover for the L100 could be very good. It uses 2nd order, 3rd, 3rd and 3rd order circuits. But it is going to be very expensive to build from scratch.
If you look at the Kasun AS-33C closely, you will see that the all 2nd order filters have component valves not too far from the DM crossover. I believe that it can even be possible to modify the Kasun by ear to make it to work and will potentially much better than JBL original no-crossover approach.
Better yet, if someone has the FRD/ZMA files for the JBL drivers, Jeff Bagby's PCD program can be used to do the simulation to see how well the Kasun crossover can do.
What I suggested is the spirit of the diyaudio.com. It is shame to dismiss it without even looking.
Hi,
If your building something for someone the time spent
really means you should do it it properly. The Kasun
is cheap and could suit an inveterate tinkerer with
time on his hands, but here with a proper solution
available, the cost, given I presume it going to be
built for free, is very reasonable at ~ $130, and
comparing that to the going rate for the drivers.
rgds, sreten.
The port ideally would be plugged too.
If your building something for someone the time spent
really means you should do it it properly. The Kasun
is cheap and could suit an inveterate tinkerer with
time on his hands, but here with a proper solution
available, the cost, given I presume it going to be
built for free, is very reasonable at ~ $130, and
comparing that to the going rate for the drivers.
rgds, sreten.
The port ideally would be plugged too.
I had a question about the british school ... I dont mean to mock, atleast not you or the british per se ...
And my first hand experience is limited to B&W (atleast in this topic) ...
OK So my series 1 603's ... they design a elaborate bracing and form fitted foam inside the bracing and call it the matrix ... and brilliantly, provide a vent on the front baffle ... with a passive radiator. So they have all this foam, but air doesn't go through it ??? and why passive and vent right next to each other ???
Then next one - the FCM8 awesome speaker IMHO, with 2 6's and 3 25mm tweeters has the famous matrix as well ... in a sealed cabinet. I can get a bit more spl, and no loss in any other aspect by removing the terminal plate and leaving it hanging to let in air ... however, this already has a bit more spl than the PCS8 woofer its paired to, and I'd rather it have about 3 dB under the woofer.
I must have not really understood "The matrix" ??? all I can say about the matrix is ... when I saw Lord of the rings ... and Hugo Weaving appears on the screen for the first time in the middle of that movie - I blurt out - Oh its the "Mr Anderson" guy from Matrix, and the whole theater went ... Oh yeaaaaaaaaa................. while my wife went ... "I dont care I'm watching this movie".
Cool.
Srinath.
Do not waste your time and money on the cheap Chinese crossovers. Either copy the original JBL or better even the Dennis Murphy version. Both you and JBL deserve better
Hi,
The foam damps internal standing waves.
PR + port seems a bizarre idea, and is not common.
It allows bass tuning, (as would two simple ports).
However by blocking the port you'll get the tightest
bass. Port open the loosest. Comes with two foam
bungs. One is for blocking, the other less dense
one gives an effect somewhere between the above.
The scheme would work with two ports.
rgds, sreten.
I am surprised that you said "original JBL" and "Dennis Murphy" in the same breath. They are worlds apart.
There is no hope for the original JBL if you read the Leesonic posted at AK and the original mod swerd posted at audio heritage.
http://www.diyaudio.com/forums/multi-way/182612-jbl-l100-restoration-upgrade-2.html
New crossover design for L-100A
Yes, go with the DM crossover if you want to have proven results.
The cheap ($42 a pair) Chinese Kasun AS-33C crossover is for the more adventueous soul with a curious mind to explore. The component values have some similiarity to the DM, but they are not the same in topology and exact components. That's the original question that deltalight asked. I selected the closest option for him.
If the Kasun does not work, you lose $42 and may savage some parts. I am very curoius whether the parts are any good. So, why not? Yes, I may try one of their 2-way sometime and will report the result if I get around to it.
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This is a bit of editorial or opinion post not exactly related to the L100 crossover.
I am by no mean imply the Kasun crossover are good quality component for the speaker builders. They are "cheap" options that give the hobbyist the affordable tools to experiment. In fact, I will not use them in the speakers I build except for testing things out. Kasun is able to keep the cost down by cutting corner in the coils. The resistance are universally high even for those inductors with ferrite core. That is an indication that they use very small gauge magnetic wire for the winding, which makes them (the inductors) unacceptable in quality. After testing them out, if you like the topology and frequency/phase response of the Kasun job, replace the inductors with better ones before closing the box.
Even with this poor quality build, I believe that a 2nd order, 3-way crossover of the right value components are going to sound much better than the JBL original approach of 2 capacitors. Those 2 capacitors are more for protection than for dividing frequencies.
Some people are turned off simply because of the "made-in-China" label. No denying that the audio goods from China are a mixed bag today. I have a Emotiva surround process (LMC-1) in my sound system that replaced the older Rotel RSP-1068. By comparison, a newer Rotel processor will cost 3 times more than a equivalent Emotiva and is unaffordable to me. Emotiva makes no bone about designing in the US and manufacturing in China to keep cost down. I also have a Tainyun Zero DAC for my home computer sound and a Topping VX-1 in my day time office.
What I am saying is that pay attention. Evaluate and judge every piece of equipment to understand their pros and cons in each case.
I am by no mean imply the Kasun crossover are good quality component for the speaker builders. They are "cheap" options that give the hobbyist the affordable tools to experiment. In fact, I will not use them in the speakers I build except for testing things out. Kasun is able to keep the cost down by cutting corner in the coils. The resistance are universally high even for those inductors with ferrite core. That is an indication that they use very small gauge magnetic wire for the winding, which makes them (the inductors) unacceptable in quality. After testing them out, if you like the topology and frequency/phase response of the Kasun job, replace the inductors with better ones before closing the box.
Even with this poor quality build, I believe that a 2nd order, 3-way crossover of the right value components are going to sound much better than the JBL original approach of 2 capacitors. Those 2 capacitors are more for protection than for dividing frequencies.
Some people are turned off simply because of the "made-in-China" label. No denying that the audio goods from China are a mixed bag today. I have a Emotiva surround process (LMC-1) in my sound system that replaced the older Rotel RSP-1068. By comparison, a newer Rotel processor will cost 3 times more than a equivalent Emotiva and is unaffordable to me. Emotiva makes no bone about designing in the US and manufacturing in China to keep cost down. I also have a Tainyun Zero DAC for my home computer sound and a Topping VX-1 in my day time office.
What I am saying is that pay attention. Evaluate and judge every piece of equipment to understand their pros and cons in each case.
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