Mod Note: This thread was split from Portable sound system gallery... in the class d forum.
In the meanwhile I tested a few other small (3" or 8cm...) fullrange drivers (instead of the 2" Visaton FR7).
Perhaps I should clear a bit on my methods and equipment. I made another couple of PVC enclosures, this material is not ideal for getting the best results. But the tests are based upon comparison between drivers, and the enclosures I used are about the same (only tweaked the stuffing a bit...). All were tested on AMP32 and AMP9 from http://www.41hz.com on SMPS supply. All drivers were optimized by PLXXO notch filters and run through 1:2/1:4 (switcheable) audio transformers to boost up the voltage a bit from my MP3, MD and CD portable players (and compensate for the loss by the filters). The signal run through both the transformer and filter
has a bit more gain and has much better bass and highs. The transformer is mainly responsible for the bass enhancement, the filter does both (and takes away that mid-high range edge that most fullrange drivers suffer from)... I made two filters, both are adjustable with a potmeter to simply go from "SHOOOOUUUT" to "BOOM~boom~PSS~pss~PSS...
but one even has switches for two different cap values and three different resistor values added All in 'mini' aluminum diamond plate chassis (as usual
Visaton FR8:
http://www.visaton.de/de/chassis_zubehoer/breitband/fr8_8.html
Good efficiency, but a lot of distortion and pretty 'canny' sound. Even with notchfilters I couldn't manage to get real good sound from it...
But for applications where soundquality is less important a pretty nice driver for what it costs... I do think the foam edge isn't going to last very long (with central heating at home those can pulverize within about six years....)
Visaton FRS8:
http://www.visaton.de/de/chassis_zubehoer/breitband/frs8_4.html
Quite a revelation compared to the FR8 in soundquality, but the efficiency is pretty low. A heavier magnet, larger voice coil and rubber edge justify the higher price. In fact I think they're better value for money. The one thing that does bother me is that it definately needs a tweeter, the highs are (especially when compared to my next candidate) just not there enough. This makes the sound a bit dull, and on top of that the higher midrange area sounds rather coarse. Overall the FRS8 sounds nicer than the FR8, the whole frequency band under 8K is very clean, flat and shows low enough distortion to listen to for long sessions (but with a tweeter...).
Next up (and the latest I tested) Monacor SPH-30X:
http://www.bmm-electronics.nl/Product.asp?Product_ID=5573
The extra you pay for this driver is payed back in equal amounts of soundquality. The bass is phenomenal (for such a small driver...), it's light (because it has a neodymium magnet) and magnetically shielded, made from very durable materials, shows very litlle distortion, handles quite a lot of power and the efficiency is GREAT! Not even speaking of the very fine high frequency resolution and the good staging that goes with that. Absolutely the winner!
A lot seems to do with the good construction of the driver, like the rubber edge is really thin and flexible which saves energy I think. The voice coil windings can be seen through openings behind the spider, this driver is very well ventilated. Also the basket is from one piece of steel all around the magnet, large and reliable connections are riveted to it 180 degrees apart with nice looking litz wires going to the voice coil. It all has a slight 'Morel' feeling to it, they also use steel baskets the same way. And last, but not unimportant to me, it looks very good IMHO (no glued wires visible around the dustcap...) An a+ in my book!
Special thanks go out for Planet10 for his great site:
http://www.t-linespeakers.org/
http://www.t-linespeakers.org/tech/filters/passiveHLxo.html
He has put theory on PLLXO filters on this site in a very understandable way. Very nice documentation for DIYers, good work man!
For the record, all this has nothing to do with HIFI! Allthough it comes verdraaid* close!
*Dutch word for which I have no translation that will pass the censoring, though it doesn't mean anything offending in my language...but I think anyone can understand from the context
In the meanwhile I tested a few other small (3" or 8cm...) fullrange drivers (instead of the 2" Visaton FR7).
Perhaps I should clear a bit on my methods and equipment. I made another couple of PVC enclosures, this material is not ideal for getting the best results. But the tests are based upon comparison between drivers, and the enclosures I used are about the same (only tweaked the stuffing a bit...). All were tested on AMP32 and AMP9 from http://www.41hz.com on SMPS supply. All drivers were optimized by PLXXO notch filters and run through 1:2/1:4 (switcheable) audio transformers to boost up the voltage a bit from my MP3, MD and CD portable players (and compensate for the loss by the filters). The signal run through both the transformer and filter
has a bit more gain and has much better bass and highs. The transformer is mainly responsible for the bass enhancement, the filter does both (and takes away that mid-high range edge that most fullrange drivers suffer from)... I made two filters, both are adjustable with a potmeter to simply go from "SHOOOOUUUT" to "BOOM~boom~PSS~pss~PSS...
but one even has switches for two different cap values and three different resistor values added All in 'mini' aluminum diamond plate chassis (as usual Visaton FR8:
http://www.visaton.de/de/chassis_zubehoer/breitband/fr8_8.html
Good efficiency, but a lot of distortion and pretty 'canny' sound. Even with notchfilters I couldn't manage to get real good sound from it...
But for applications where soundquality is less important a pretty nice driver for what it costs... I do think the foam edge isn't going to last very long (with central heating at home those can pulverize within about six years....)
Visaton FRS8:
http://www.visaton.de/de/chassis_zubehoer/breitband/frs8_4.html
Quite a revelation compared to the FR8 in soundquality, but the efficiency is pretty low. A heavier magnet, larger voice coil and rubber edge justify the higher price. In fact I think they're better value for money. The one thing that does bother me is that it definately needs a tweeter, the highs are (especially when compared to my next candidate) just not there enough. This makes the sound a bit dull, and on top of that the higher midrange area sounds rather coarse. Overall the FRS8 sounds nicer than the FR8, the whole frequency band under 8K is very clean, flat and shows low enough distortion to listen to for long sessions (but with a tweeter...).
Next up (and the latest I tested) Monacor SPH-30X:
http://www.bmm-electronics.nl/Product.asp?Product_ID=5573
The extra you pay for this driver is payed back in equal amounts of soundquality. The bass is phenomenal (for such a small driver...), it's light (because it has a neodymium magnet) and magnetically shielded, made from very durable materials, shows very litlle distortion, handles quite a lot of power and the efficiency is GREAT! Not even speaking of the very fine high frequency resolution and the good staging that goes with that. Absolutely the winner!
A lot seems to do with the good construction of the driver, like the rubber edge is really thin and flexible which saves energy I think. The voice coil windings can be seen through openings behind the spider, this driver is very well ventilated. Also the basket is from one piece of steel all around the magnet, large and reliable connections are riveted to it 180 degrees apart with nice looking litz wires going to the voice coil. It all has a slight 'Morel' feeling to it, they also use steel baskets the same way. And last, but not unimportant to me, it looks very good IMHO (no glued wires visible around the dustcap...) An a+ in my book!Special thanks go out for Planet10 for his great site:
http://www.t-linespeakers.org/
http://www.t-linespeakers.org/tech/filters/passiveHLxo.html
He has put theory on PLLXO filters on this site in a very understandable way. Very nice documentation for DIYers, good work man!
For the record, all this has nothing to do with HIFI! Allthough it comes verdraaid* close!
*Dutch word for which I have no translation that will pass the censoring, though it doesn't mean anything offending in my language...but I think anyone can understand from the context
Oh yes, if you want to know more theory I used to make the notchfilter:
http://www.audioasylum.com/forums/hug/messages/120394.html
The coils I wound myself (15 minutes per coil with a fixed electrical drill from a large spool of enameled ofc copperwire I have, cores are made from a stack of six plates of steel from an E-I core transformer).
On the Monacor I use a 3K resistor from the source and paralleled a series network of a 154nF capacitor followed by a 97mH coil and a 10K potmeter to ground, don't know if I've done everything right here, but I tweaked it a lot and got to a nice setup for each different driver IMO.
The FRS8 sounded nicer with a 5K resistor from the source, 330nF cap, 110mH coil and also a 10K pot.
For FR8 I'm not sure...
By the way, I tested FR7, FR8, FRS8 in both 4 ohm and 8 ohm versions. Nothing really dramatically different here, except for the obvious...
Monacor SPH-30X I only have in 8 ohm version (least distortion, still enough power...)
http://www.audioasylum.com/forums/hug/messages/120394.html
The coils I wound myself (15 minutes per coil with a fixed electrical drill from a large spool of enameled ofc copperwire I have, cores are made from a stack of six plates of steel from an E-I core transformer).
On the Monacor I use a 3K resistor from the source and paralleled a series network of a 154nF capacitor followed by a 97mH coil and a 10K potmeter to ground, don't know if I've done everything right here, but I tweaked it a lot and got to a nice setup for each different driver IMO.
The FRS8 sounded nicer with a 5K resistor from the source, 330nF cap, 110mH coil and also a 10K pot.
For FR8 I'm not sure...
By the way, I tested FR7, FR8, FRS8 in both 4 ohm and 8 ohm versions. Nothing really dramatically different here, except for the obvious...
Monacor SPH-30X I only have in 8 ohm version (least distortion, still enough power...)
Hi, no I haven't, very interesting drivers they make, but none of them really seemed to match the profile. They either have phase plugs (which menas dust and water can enter the magnet gap), or they didn't have the nicely light neodyme magnet, or just paper cone...
The price/quality seems very good, for inside use they would perhaps be my choice...
The price/quality seems very good, for inside use they would perhaps be my choice...
Interestingly enough, these FR8 and SPH30X exhibit the same single sine wave pulse looking response around 3kHz and have a peak in the response around 10kHz. The FRS8 on the other hand has a much smoother response and no peaking at 10kHz. The FR8 and SPH30X are also more sensitive than the FRS8. Judging just from the frequency response the FRS8 should have been the winner. You mentioned that you thought the FRS8 "definitely needs a tweeter" indictaing that, like many, you prefer a rising treble response OR have less hearing sensitivity to higher frequencies. I know I can't hear over 17kHz...
Hello,
an alternative with good sound is
the FRS8M Visaton, Omnes audio 3.01.
free download plan for two driver:
http://www.hm-moreart.de/24.htm
an alternative with good sound is
the FRS8M Visaton, Omnes audio 3.01.
free download plan for two driver:
http://www.hm-moreart.de/24.htm
Attachments
Bwrx: The FRS-8 should indeed show a nicely flat response, but my experience is they sound quite matte... I confirmed this more or less with a portable spectrum analizer borrowed from a collegue. Or maybe my ears are going down, maybe I should have them tested first
The other drivers (FR8 and SPH30X) indeed show some harshness without the filter. The FR-8 is incurable in this IME, I tried many filter configurations.
The SPH-30X on the other hand keeps a high dose of finesse and detail richness in the high frequency range. Though without the filter it sounds overbright and a bit coarse in the higher mids...
The FRS-8M is one of the newer drivers in this size from Visaton isn't it?
Very nice design, 360 degree radiation rules!
Next thing I was thinking about is to create a subsonic filter to protect the small drivers a bit from the bass peaks...So I'm thinking notch@10Khz and highpass@80hz...
Any ideas would be very welcome...
The other drivers (FR8 and SPH30X) indeed show some harshness without the filter. The FR-8 is incurable in this IME, I tried many filter configurations.
The SPH-30X on the other hand keeps a high dose of finesse and detail richness in the high frequency range. Though without the filter it sounds overbright and a bit coarse in the higher mids...
The FRS-8M is one of the newer drivers in this size from Visaton isn't it?
Very nice design, 360 degree radiation rules!
Next thing I was thinking about is to create a subsonic filter to protect the small drivers a bit from the bass peaks...So I'm thinking notch@10Khz and highpass@80hz...
Any ideas would be very welcome...
Did some measurements on the filter and the combination with Monacor SPH-30X...
I immediately changed some components to raise the frequency on which it filters (the dip is now @ 2.2Khz, still quite wide range...)
Here's what I had initially created, and sounds quite nice...
It was measured with the potmeter in max. filter setting...
I immediately changed some components to raise the frequency on which it filters (the dip is now @ 2.2Khz, still quite wide range...)
Here's what I had initially created, and sounds quite nice...
It was measured with the potmeter in max. filter setting...
Attachments
In real life it's a big plus IMO. The highs don't sound harsh at all, rather delicate and detailed. Note the measurements were done pretty close-up, from larger (listening) distance the higher frequencies normally stay more behind. At least it gives a tonal balance that makes you suspect a tweeter is used.
The system I use it for was never intended to become hifi, otherwise I would have used a wooden cabinet. Instead I used a PVC enclosure...
But for a 1 liter enclosure with two 3" fullrange speakers (stereo from 1 box...) I (and many others) think it sounds phenomenal!
The system I use it for was never intended to become hifi, otherwise I would have used a wooden cabinet. Instead I used a PVC enclosure...
But for a 1 liter enclosure with two 3" fullrange speakers (stereo from 1 box...) I (and many others) think it sounds phenomenal!
I very dislike the idea of cone treatment, it's so permanent...And perhaps makes what sounds very rich now sound dull afterwards...
Perhaps I can start by sticking a piece of self adhesive foam on the dustcap (so it can be removed again...).
Anyway, I know about the difference between measurements and real life situations, I own ESL speakers for funk sake!
My posting these measurement is merely to give a slight insight in the system, intended for those (experts, gurus) who also know the difference. Not to draw conclusions out of, or claiming I did the right thing. I can think of a million things to get that line straight in the FR graph, but it doesn't have to sound better, I agree...
I do think (or actually know from experience) that a wooden enclosure would perform much better (both audible and measurable) for example...
What exactly is a twin t filter? I'd like to know...thanks....
Perhaps I can start by sticking a piece of self adhesive foam on the dustcap (so it can be removed again...).
Anyway, I know about the difference between measurements and real life situations, I own ESL speakers for funk sake!
My posting these measurement is merely to give a slight insight in the system, intended for those (experts, gurus) who also know the difference. Not to draw conclusions out of, or claiming I did the right thing. I can think of a million things to get that line straight in the FR graph, but it doesn't have to sound better, I agree...
I do think (or actually know from experience) that a wooden enclosure would perform much better (both audible and measurable) for example...
What exactly is a twin t filter? I'd like to know...thanks....
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