Just for the fun I have build a small version of Chops woofer, using 2 old 8 inch woofers from a stereo console of the 70’s!
It was just a joke to see if it really functions. I am driving it with a subwoofer plate amp made by Visaton. The result is very good indeed. Great definition and speed, much better than with the same speaker in a closed cabinet.
🙂
It was just a joke to see if it really functions. I am driving it with a subwoofer plate amp made by Visaton. The result is very good indeed. Great definition and speed, much better than with the same speaker in a closed cabinet.
🙂
rxc said:
This right here. It's a Carver M-400t running at 4 ohms stereo (300 watts X 2). 😀
An externally hosted image should be here but it was not working when we last tested it.
Just as an added note, 300 watts per channel for these subs is more than enough power to get them louder than the actual performance. See those output LED meters? I've never seen them go higher that the second ones up from the bottom! And I've hit 98dB at 20Hz with these already with probably no more than a 1/4 of the total output power of this amp! 😀
Considering that this amp is 20 years old, it's probably a good thing that it's not having to work hard to do what I need it to do. In fact, this amp runs cold all day long!
Considering that this amp is 20 years old, it's probably a good thing that it's not having to work hard to do what I need it to do. In fact, this amp runs cold all day long!
Hi All
(My first post)
Will this Sub work as a DIpole ?
SP-382C Monacor carpower 15"
Impedance (Z) 4 Ohm
Frequency range 30–4,000Hz
Free air resonance (fs) 30Hz
Crossover frequency (12dB/oct.) (fmax) 1,500Hz
Peak music power 500W
Power rating 220WRMS
SPL (1W/1m) 94dB
Cms suspension compliance 0.31mm/N
Mms moving mass 90g
Qms mech. Q factor 4.55
Qes electrical Q factor 1.78
Qts total Q factor 1.2
Vas compl. equiv. vol. 320 l
RDC DC resistance (Re) 3.8 Ohm
Voice coil ind. (1kHz) (Le) 0.45mH
Voice coil diameter 50mm
Voice coil former aluminium
Air gap height 6mm
Force factor WxL 6.0Tm
Eff. cone area 855cm²
Magnet diameter 140mm
Magnet weight 40oz.
Mounting cutout ø 353mm
Mounting depth 150mm
Dimensions ø 382mm
Weight 3.7kg
(My first post)
Will this Sub work as a DIpole ?
An externally hosted image should be here but it was not working when we last tested it.
SP-382C Monacor carpower 15"
Impedance (Z) 4 Ohm
Frequency range 30–4,000Hz
Free air resonance (fs) 30Hz
Crossover frequency (12dB/oct.) (fmax) 1,500Hz
Peak music power 500W
Power rating 220WRMS
SPL (1W/1m) 94dB
Cms suspension compliance 0.31mm/N
Mms moving mass 90g
Qms mech. Q factor 4.55
Qes electrical Q factor 1.78
Qts total Q factor 1.2
Vas compl. equiv. vol. 320 l
RDC DC resistance (Re) 3.8 Ohm
Voice coil ind. (1kHz) (Le) 0.45mH
Voice coil diameter 50mm
Voice coil former aluminium
Air gap height 6mm
Force factor WxL 6.0Tm
Eff. cone area 855cm²
Magnet diameter 140mm
Magnet weight 40oz.
Mounting cutout ø 353mm
Mounting depth 150mm
Dimensions ø 382mm
Weight 3.7kg
We have been here before. 😉 The big question is what is the Xmax for this driver.
It also looks like a pretty basic pressed steel basket that could be mechanically noisy.
hi
these are very cheap , chinese sourced pa drivers , these will never go down to sub frequencies
to go down real down you need excursion , and belive me a pro audio suround (inteneded) driver never does well in domestic
look for a large roll _ natural rubber reinforced non -press paper cone with a minimum x - max of 25 mm one way
with preferable a large progressive roll spider
other wise forget di pole all driver non linearity , flapping and spider resonance will be audible speacially when you power the second speaker
try this power any one of the driver it will sound good - distortion free , power both together , it wont sound the same
suranjan
transducer design engineer
these are very cheap , chinese sourced pa drivers , these will never go down to sub frequencies
to go down real down you need excursion , and belive me a pro audio suround (inteneded) driver never does well in domestic
look for a large roll _ natural rubber reinforced non -press paper cone with a minimum x - max of 25 mm one way
with preferable a large progressive roll spider
other wise forget di pole all driver non linearity , flapping and spider resonance will be audible speacially when you power the second speaker
try this power any one of the driver it will sound good - distortion free , power both together , it wont sound the same
suranjan
transducer design engineer
hunter audio said:
Ummm...... apparently you haven't been paying attention to this whole thread.
1) The drivers I'm using are designed for pro audio use. Guess what? I'm using them at home in a DIPOLE configuration and I can guarantee that you can definantly get audiophile sound from them if used properly.
2) They have stamped steel baskets, folded cloth surrounds, an XMAX of only 4mm, and an Fs of 26Hz. I am almost willing to bet that not even you have heard a better sounding subwoofer system like mine. And with a flat frequency response from 90Hz to below 20Hz, you can't go wrong.
By the way, did I mention I'm the one who started this huge thread?!
Here's a couple pictures of the drivers..... you know, the kind you say are "flapping and non-linear".
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I wonder if the mechanical demands on a driver used in dipole configuration, ie not in a box, mean that the actual quality/specification of the driver is less important.
This is a question rather than a statement.
And while every man and his dog shouts about maximum excursion, here we have Chops with excellent results from drivers with only 4mm Xmax. And, it seems Mentero too!
I can't help thinking that sometimes (not always), there is a wide gap between theory and practise in the world of hi-fi.
As an example, room effects will swamp minor anomalies with subwoofer output so trying to build a 'perfect' sub is a good goal but not really achievable so we may as well accept some compromises along the way.
This is a question rather than a statement.
And while every man and his dog shouts about maximum excursion, here we have Chops with excellent results from drivers with only 4mm Xmax. And, it seems Mentero too!
I can't help thinking that sometimes (not always), there is a wide gap between theory and practise in the world of hi-fi.
As an example, room effects will swamp minor anomalies with subwoofer output so trying to build a 'perfect' sub is a good goal but not really achievable so we may as well accept some compromises along the way.
Nuuk,
'The early bird gets the worm but the second mouse gets the cheese.' -hehe 😉
Nice pics chops, bet ya have a good digicam 🙂
'The early bird gets the worm but the second mouse gets the cheese.' -hehe 😉
Nice pics chops, bet ya have a good digicam 🙂
Good question. However, I would imagine that the spec would be just as important for an Open Baffle as it is for any other enclosure out there
See, I'll tell you the reasons why I think my choice of drivers worked out perfectly for me, as they would for anyone else.....
1) Siegfried tells us that for the least amount of EQ compensation, we should look for a driver with a total Q of at least .60 or there abouts. So what does everybody end up buying, including Siegfried?
A: Those stupid Pearless drivers with exactly the opposite specs for dipole usage and with a lot lower Q than needed, hence the very much needed extra EQ'ing.
B: I stick with Mr. Linkwitz's specs and buy a driver with a total Q of .67, which in turn needs very little to no EQ'ing at all.
2) Siegfried also tells us that we need a driver with a high X-max. Why?
A: Because everyone including Mr. Linkwitz is using those Pearless drivers which are very inefficient (85dB I think), combined with very small open baffles which makes things even less efficient. The high X-max is needed because you have to dump a lot of power into them to get any decent amount of volume out of them, due to the low efficiency and the small baffles.
B: This is where I take the "unbeated path" so to speak. I figure if I get a driver that is efficient (93dB), it will not have to travel as far to create enough volume. Fortunantly for me, I was right and ended up with a set of 15" drivers that hardly move at any volume or frequency. The other helping factor here is the much larger baffles I chose to build.
3) We are told to get a driver with a low Fs.
A: The Pearless driver does have this right with an Fs of 18Hz if my memory serves me right. However this is rendered virtually useless since they are always mounted to tiny open baffles, hence the lack of any true bass below 40Hz and requiring the help of a mono-pole subwoofer stuck in the corner to reproduce the frequencies from 40Hz down. If you ask me, that defeats the purpose of even building dipoles in the first place if you're having to resort back to a mono-pole sub.
B: The Fs on my drivers are 26Hz. I also have much larger baffles which I think is very much needed. Obviously, I'm correct on this as well since my subs are virtually flat all the way down to at least 20Hz if not lower on thier own, WITHOUT the help of a mono-pole sub or a whole bunch of EQ. Remember, larger baffles means lower frequency output.
All in all, what I'm trying to say is that designing and building dipole subs is like cooking, you DO NOT have to exactly go by the recipe in order to get great results! And I prove this point very well.
See, I'll tell you the reasons why I think my choice of drivers worked out perfectly for me, as they would for anyone else.....
1) Siegfried tells us that for the least amount of EQ compensation, we should look for a driver with a total Q of at least .60 or there abouts. So what does everybody end up buying, including Siegfried?
A: Those stupid Pearless drivers with exactly the opposite specs for dipole usage and with a lot lower Q than needed, hence the very much needed extra EQ'ing.
B: I stick with Mr. Linkwitz's specs and buy a driver with a total Q of .67, which in turn needs very little to no EQ'ing at all.
2) Siegfried also tells us that we need a driver with a high X-max. Why?
A: Because everyone including Mr. Linkwitz is using those Pearless drivers which are very inefficient (85dB I think), combined with very small open baffles which makes things even less efficient. The high X-max is needed because you have to dump a lot of power into them to get any decent amount of volume out of them, due to the low efficiency and the small baffles.
B: This is where I take the "unbeated path" so to speak. I figure if I get a driver that is efficient (93dB), it will not have to travel as far to create enough volume. Fortunantly for me, I was right and ended up with a set of 15" drivers that hardly move at any volume or frequency. The other helping factor here is the much larger baffles I chose to build.
3) We are told to get a driver with a low Fs.
A: The Pearless driver does have this right with an Fs of 18Hz if my memory serves me right. However this is rendered virtually useless since they are always mounted to tiny open baffles, hence the lack of any true bass below 40Hz and requiring the help of a mono-pole subwoofer stuck in the corner to reproduce the frequencies from 40Hz down. If you ask me, that defeats the purpose of even building dipoles in the first place if you're having to resort back to a mono-pole sub.
B: The Fs on my drivers are 26Hz. I also have much larger baffles which I think is very much needed. Obviously, I'm correct on this as well since my subs are virtually flat all the way down to at least 20Hz if not lower on thier own, WITHOUT the help of a mono-pole sub or a whole bunch of EQ. Remember, larger baffles means lower frequency output.
All in all, what I'm trying to say is that designing and building dipole subs is like cooking, you DO NOT have to exactly go by the recipe in order to get great results! And I prove this point very well.
zygibajt said:
93dB @ 1 watt.
SimontY said:
Those pics were taken with an Olympus C-3020 3.2MP digital camera. I have since replaced that with a Nikon CoolPix 990 3.2MP digital camera. Same megapixels but better optics and alot more flexible as far as external lens and flash options.
http://www.partsexpress.com/pe/show...St3=-58692660&DS_ID=3&Product_ID=118185&DID=7
The price isn't too bad, although Qts could be higher.
The price isn't too bad, although Qts could be higher.
Anyone tried these in a dipole sub?
Thinking of getting four of parts express 290-268 18" woofers for a pair of W cabinets.
Specs:
Fs: 24.56 Hz
SPL: 93.5 dB 1W/1m
Vas: 31.8 cu. ft.
Qms: 8.12
Qes: .91
Qts: .82
Xmax: 4.6mm
Nominal impedance: 8 ohms
DC resistance: 7.2 ohms
I know the Xmax is a little short, but with the cone area I doubt I'll have too much trouble moving air. Also, the baffle will necissarily be larger just to fit the 18" woofers, which should also lower my excursion requirements...
Peace
Thinking of getting four of parts express 290-268 18" woofers for a pair of W cabinets.
Specs:
Fs: 24.56 Hz
SPL: 93.5 dB 1W/1m
Vas: 31.8 cu. ft.
Qms: 8.12
Qes: .91
Qts: .82
Xmax: 4.6mm
Nominal impedance: 8 ohms
DC resistance: 7.2 ohms
I know the Xmax is a little short, but with the cone area I doubt I'll have too much trouble moving air. Also, the baffle will necissarily be larger just to fit the 18" woofers, which should also lower my excursion requirements...
Peace
Good man Chops! 😉 There's no substitute for reading the guidelines and then thinking for yourself as you have proved.
Thanks Nuuk! That's basically how I've always done things, including in the kitchen! And you want to know something? ....It usually works out if you use your head and not rush into things.
I just don't want people getting told the wrong thing or other people bashing someone's choice of brand just because they think they know what they're talking about.
This thread has alot of real good information in it for beginners as well as the advanced members. I'm sure that over the past year, members have seen me evolve a bit. At least I hope so! lol
But just like in any forum or life for that matter, you're gonna run into a few "sour eggs" that think they know best and only their way is the correct way. Oh well. 😉
I just don't want people getting told the wrong thing or other people bashing someone's choice of brand just because they think they know what they're talking about.
This thread has alot of real good information in it for beginners as well as the advanced members. I'm sure that over the past year, members have seen me evolve a bit. At least I hope so! lol
But just like in any forum or life for that matter, you're gonna run into a few "sour eggs" that think they know best and only their way is the correct way. Oh well. 😉
hi
thanks nuuk for the pics of the drivers , they have presented a better picture to me
were these driver sourced from parts express as just the spider and the surround quality and form suggest that these are well made drivers , i exactly am confused with the parts express drivers
your flat curve and frequency responce suggests your satisfaction
would be interested in any distortion audible at high volume levles type of a test report
thanks
suranjan das gupta
transducer design engineer
thanks nuuk for the pics of the drivers , they have presented a better picture to me
were these driver sourced from parts express as just the spider and the surround quality and form suggest that these are well made drivers , i exactly am confused with the parts express drivers
your flat curve and frequency responce suggests your satisfaction
would be interested in any distortion audible at high volume levles type of a test report
thanks
suranjan das gupta
transducer design engineer
chops said:
I certainly am no fan of those XLS drivers, but low Q_es (= high Bxl) drivers do have their merits, namely low thermal compression and low magnetic intermodulation distortion. The quickest way to "equalize" them is to run them through a series resistor big enough to render total Q=0.6. You will obtain roughly the same sensitivity as you would have gotten with a weaker magnet but with lower compression and distortion.
If you go active anyway, a Linkwitz transform is no big deal, and neither do you have to worry about low voltage sensitivity.
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