I have a LARGE pair of two way speakers, which i rebuilt when the original cabinets went south. They originally had passive radiators.
I made the new cabinets huge stand mounted two ways, instead of floor standing. But i can cut holes in the sides for new passive radiators.
Issue is, they have a 10" woofer/midbass ... and came with a tuned 10" passive from the manufacturer.
I have always went larger than the driver, with a pasaive radiator choice.
So should i go back with what the same sized factory replacement is, or use a 12 or even 15 inch passive of my choice?
I made the new cabinets huge stand mounted two ways, instead of floor standing. But i can cut holes in the sides for new passive radiators.
Issue is, they have a 10" woofer/midbass ... and came with a tuned 10" passive from the manufacturer.
I have always went larger than the driver, with a pasaive radiator choice.
So should i go back with what the same sized factory replacement is, or use a 12 or even 15 inch passive of my choice?
More important is how much the old passives weighed. Did they have mass attached to the diaphragm? That tunes the resonance of the passive.
Im not positive if they published the cone weight of the non adjustable passive they provided. It may have simply been made to weight spec, since it is not adjustable.
Then again, Im not sure if ESS has any real engineers. No joking. They rate their completed speakers sensitivity using the amt's rated sensitivity, to make their specs more impressive. When i asked about the woofer's sensitivity after baffle step loss, they replied with "huh"?
Then again, Im not sure if ESS has any real engineers. No joking. They rate their completed speakers sensitivity using the amt's rated sensitivity, to make their specs more impressive. When i asked about the woofer's sensitivity after baffle step loss, they replied with "huh"?
ESS sells new passives in 10 and 12 inch. Did they have any wisdom to impart on the passive size and weight?
The 10" FOAM radiator they recommend for this driver, weighs 54g ... the 12" foam weighs 79g. The 10" nicer radiator with basket weighs 154g.
Wish I could find an adjustable passive that starts at 50g unweighted
Wish I could find an adjustable passive that starts at 50g unweighted
Hi Flaxxer
You should try to simulate the system before anything.
What you have as a 10" ESS in a closed box of size?
Maybe you can find the T/S parameters on the web or someone have a similar driver and could make a measurement e.g. with DATS.
... is it this one: https://www.hifisound.de/Do-it-your...SS-Woofer-10-Zoll-25-cm-ALU-Basket-4-OHM.html ?
Then use WinISD for simulating the system, first without a passive and then with.
You could also just make it a ported design? Or at least to start with.
Ported and passive radiator performance is very similar. The big advantage of a passive is when used in small cab subwoofers, where a port would need to be very long for a low tuning and with a large enough diameter or cross section to minimize coughing.
But if you cap is relatively large and the tuning freq is not very low, then a port can be a very good and easy alternative.
I would think an alternative to an ESS passive could be one of the Dayton ones (e.g. 2xDS270-PR), as you are not doing a sub (which would require something with a much heavier diaphragm)
You should try to simulate the system before anything.
What you have as a 10" ESS in a closed box of size?
Maybe you can find the T/S parameters on the web or someone have a similar driver and could make a measurement e.g. with DATS.
... is it this one: https://www.hifisound.de/Do-it-your...SS-Woofer-10-Zoll-25-cm-ALU-Basket-4-OHM.html ?
Then use WinISD for simulating the system, first without a passive and then with.
You could also just make it a ported design? Or at least to start with.
Ported and passive radiator performance is very similar. The big advantage of a passive is when used in small cab subwoofers, where a port would need to be very long for a low tuning and with a large enough diameter or cross section to minimize coughing.
But if you cap is relatively large and the tuning freq is not very low, then a port can be a very good and easy alternative.
I would think an alternative to an ESS passive could be one of the Dayton ones (e.g. 2xDS270-PR), as you are not doing a sub (which would require something with a much heavier diaphragm)
Another advantage of applying a PR in a 2-way is the absence of port resonance output. Anyway, most use a larger PR than the driver itself, the volume displacement of a reflex system at tuning is equal to 3 to 6dB higher sound output than that of a comparable closed box. And big excursions come with big nonlinearities in suspension.
You have the same high excursions with a passive as with a reflex system. These two systems are very similar in all respect, and very different from a closed box.
Just apply a high pass filter at the tuning resonance to limit the excursion. The high excursion occurs below tuning freq. Otherwise the excursion is same or less than for a closed box system.
ESS 10" in 50 l (not sure it's the right 10" or wether the parameters are correct ... just the one I had in WinISD, and just for example)
Green = reflex, Pink = passive, Blue = closed. Input 35V
Just apply a high pass filter at the tuning resonance to limit the excursion. The high excursion occurs below tuning freq. Otherwise the excursion is same or less than for a closed box system.
ESS 10" in 50 l (not sure it's the right 10" or wether the parameters are correct ... just the one I had in WinISD, and just for example)
Green = reflex, Pink = passive, Blue = closed. Input 35V
Attachments
SOP is to go at least one size larger, but then tune the mass.
I always suggest a high pass filter on any driver. Even subs. Where and how steep you need to look at the excursion plot to decide. But, to keep component sizes in check, best to do the woofer HP electronically. I set it up in EQ APO on a couple of systems,
I always suggest a high pass filter on any driver. Even subs. Where and how steep you need to look at the excursion plot to decide. But, to keep component sizes in check, best to do the woofer HP electronically. I set it up in EQ APO on a couple of systems,
To clear up some things ... I did not redesign the factory speakers. I am using the same xover, drivers, and enclosure volume. I kept the front baffle the same with with the drivers in the same place on the baffles. The only thing I did was change it from floor standing to a much deeper and humongous two way. I originally rebuilt it without the passive because I thought it would make the bass a little tighter. Knowing I could later cut holes and add passes if I chose to. Then it hit me, the passives were boosting the efficiency of the entire speaker system. So getting rid of them made my speakers now less efficient. I could always add new factory foam radiators back on, but have read everywhere this is a very bad idea. I was told he's foam pieces have no structural rigidity and flop around a lot and do not make the best bass assist.
The main thing is this; I could always rebuild it exactly like the speaker came from the factory with the factory 10-inch passed it. But we all know I should be using a larger passive than the woofer. Apparently ESS did not care or know this. My question is, do I go back with a trashy design they came up with, or do I try to improve it by using a better quality tunable passive that is larger?
The main thing is this; I could always rebuild it exactly like the speaker came from the factory with the factory 10-inch passed it. But we all know I should be using a larger passive than the woofer. Apparently ESS did not care or know this. My question is, do I go back with a trashy design they came up with, or do I try to improve it by using a better quality tunable passive that is larger?
Hi Flaxxer
I think you may give ESS a little too little credit here, saying they didn't know this or that. The original speakers where also introduced in an age where they did not have all the benefits of readily available simulation software and and abundance of knowledge right here on the net.
Again you need to simulate, otherwise you will end up doing exactly as you are writing, just taking some available passive and trying to tune it, and hoping it will be better 😉
About size og the passive vs the woofer, also depends on excursion, the displacement volume needs to be more then double that of the woofer. The ESS 10 inch I just looked at had an Xmax of only 4 mm. The Passive will likely have more then 10 mm excursion, thereby actually ensuring double displacement.
Exactly which woofers do you have?
What is the volume of the box?
With regards to the original foam passives; I would have imagined that the diaphragm is not just foam but have some more rigid core .... but I have never seen or touched one in real life. Of course it would seem that the newer ESS passives with a "real" cone and alu chassis etc, could do a better job. But one thing I'm wondering is how rigid or stiff it actually needs to be, the pressure in the box will push the membranes uniformly over the entire surface and not in a small area which is true for the woofers voice coil. Secondly, the box is rather large ... something like 50 l, and the pressure will not at all be as high as in a small high excursion sub (e.g. Sunfier True Sub).
The original ESS models are "old school" with good senility, light weight membranes, requiring big boxes, and having limited excursion.
My 2 cent
I think you may give ESS a little too little credit here, saying they didn't know this or that. The original speakers where also introduced in an age where they did not have all the benefits of readily available simulation software and and abundance of knowledge right here on the net.
Again you need to simulate, otherwise you will end up doing exactly as you are writing, just taking some available passive and trying to tune it, and hoping it will be better 😉
About size og the passive vs the woofer, also depends on excursion, the displacement volume needs to be more then double that of the woofer. The ESS 10 inch I just looked at had an Xmax of only 4 mm. The Passive will likely have more then 10 mm excursion, thereby actually ensuring double displacement.
Exactly which woofers do you have?
What is the volume of the box?
With regards to the original foam passives; I would have imagined that the diaphragm is not just foam but have some more rigid core .... but I have never seen or touched one in real life. Of course it would seem that the newer ESS passives with a "real" cone and alu chassis etc, could do a better job. But one thing I'm wondering is how rigid or stiff it actually needs to be, the pressure in the box will push the membranes uniformly over the entire surface and not in a small area which is true for the woofers voice coil. Secondly, the box is rather large ... something like 50 l, and the pressure will not at all be as high as in a small high excursion sub (e.g. Sunfier True Sub).
The original ESS models are "old school" with good senility, light weight membranes, requiring big boxes, and having limited excursion.
My 2 cent
You actually gave me good information Baldin. The reason I'm down on ESS was a 20-minute phone call to their head engineer about eight months ago. He was really confused by the most generic speaker building terms like baffle step compensation. It left me floored that they would be selling new designs and not have anyone understanding speaker design at all. But I thought I should address a few of your suggestions and questions. First of all, the foam passive is a piece of Styrofoam about three quarters of an inch thick, with a piece of cardboard for weight glue to the back side, and thin weightless black foam for appearance on the front. That's all there is to it. It very well may be just enough to be perfect for the 10. I had actually not been thinking about the small 4 millimeter Excursion. I assume this changes how big the passive has to be? I was not trying to get better sound, just buy a better product than the foam passive appears to be. I guess I may be overthinking things here. I ran into trouble finding a better made passive radiator that had a lack of weight to begin with. Finding one who's cone alone weighs 54 G is nearly impossible. Almost everything starts at closer to 150 g and up. I kept the cabinet volume the exact same size as the original cabinet. I just changed the shape of it. So it should be tuned exactly the same. The only other thing that bothers me, is they changed drivers from a paper cone woofer to a coated paper polypropylene looking thing. The specs definitely changed! Yet their engineer says None of the crossover needs to be changed at all even though the speaker specs completely changed! This blew my head up alone. So that better looking passive you were talking about on the ESS site? That is for only two speakers they make. And neither of them are the older versions like I have. All of the older versions apparently use that foam thing.
https://www.simplyspeakers.com/ess-replacement-amt-woofer-689-1012.html
These are the woofers in my old speakers. The wolfers are the new version with different specs
These are the woofers in my old speakers. The wolfers are the new version with different specs