Anyone ever make copies of a big name sub?

E

edonsmith

Audioholic Intern
I have a pretty good wood working shop and was thinking about making my own sub by copying one of the good ones. I have a Madisound catalog and thye have some nice stuff.

Anyone have any tips?

Don
 
mike c

mike c

Audioholic Warlord
big manufacturers have to cut corners somewhere to sell as much as they can ..

you'd be better off studying the DIY designs on the net, because those designs don't care about aesthetics that much, and or ease of mass production.
 
T2T

T2T

Senior Audioholic
You might consider one of the "water heater" sub clones using some Sonotube. It would be an easy way to clone one of the SVS subs.
 
Buckeyefan 1

Buckeyefan 1

Audioholic Ninja
It depends on how much room you have, and how much cash you have to spend on the driver(s) and amp. Here's a few pics I like. The first is comparing a 12" to a 15" driver. The second is an IB design which requires a separate pro amp and eq, and the last a compact high powered Velodyne HGS series.







If I were building one and had the room, I'd probably like to recreate my SVS Plus/2, but using twin Dayton Hifi 15's instead of twin Plus 12's, and a scaled up cabinet. Yes, it would be huge, but once you've gotten a taste of the Plus/2, you'd get the bug.
 
S

Sounds Good

Senior Audioholic
whats the details with the clear one... thats really neat.. awesome convo piece
 
MACCA350

MACCA350

Audioholic Chief
Sounds Good said:
whats the details with the clear one... thats really neat.. awesome convo piece
Velodyne HGS-10 Powered Subwoofer

10" Driver -Sealed Box, Servo-Feedback

Manufacturer's FR Specs: 20 Hz - 125 Hz ± 3 dB

Built-in Amplifier: 1,000 watts rms

Size: 11" H x 11" W x 11" D

Weight: 36 pounds

Price: $1,595 USA (Black gloss finish)

Secrets review
The clear version was built for dealer display IIRC. The HGS series is about 10 years old.

cheers:)
 
jaxvon

jaxvon

Audioholic Ninja
MACCA350 said:
Velodyne HGS-10 Powered Subwoofer

10" Driver -Sealed Box, Servo-Feedback

Manufacturer's FR Specs: 20 Hz - 125 Hz ± 3 dB

Built-in Amplifier: 1,000 watts rms

Size: 11" H x 11" W x 11" D

Weight: 36 pounds

Price: $1,595 USA (Black gloss finish)

Secrets review
The clear version was built for dealer display IIRC. The HGS series is about 10 years old.

cheers:)
Judging by measurements, that sub is not a very good value. Compare the measurements here:

http://www.avtalk.co.uk/forum/index.php?t=msg&th=13373&start=0&rid=0&SQ=0

To a DIY subwoofer using an Infinity Kappa Perfect driver:

http://www.hometheatershack.com/forums/subwoofer-tests/978-diy-infinity-kappa-perfect-12-a.html

You can get the drivers here for $180/pr, shipped:

http://www.crutchfield.com/S-SGUqlET7qzw/cgi-bin/ProdView.asp?g=520&I=108PER121&search=kappa+perfect
 
mike c

mike c

Audioholic Warlord
but the HGS is servo controlled, has better extension, smaller, and once upon a time the flagship of velodyne
 
MACCA350

MACCA350

Audioholic Chief
jaxvon said:
Judging by measurements, that sub is not a very good value. Compare the measurements here:

http://www.avtalk.co.uk/forum/index.php?t=msg&th=13373&start=0&rid=0&SQ=0

To a DIY subwoofer using an Infinity Kappa Perfect driver:

http://www.hometheatershack.com/forums/subwoofer-tests/978-diy-infinity-kappa-perfect-12-a.html

You can get the drivers here for $180/pr, shipped:

http://www.crutchfield.com/S-SGUqlET7qzw/cgi-bin/ProdView.asp?g=520&I=108PER121&search=kappa+perfect
I can't connect to AVTalk at the moment but those DIY THD measurements are off the chart(literally). The question is are both those measurements actually comparable, I mean you need identical methods and test equipment to compare without bias.

cheers:)
 
WmAx

WmAx

Audioholic Samurai
MACCA350 said:
I can't connect to AVTalk at the moment but those DIY THD measurements are off the chart(literally). The question is are both those measurements actually comparable, I mean you need identical methods and test equipment to compare without bias. Note that even with comparable distortion and SPL, the subwoofer will sound different, due to frequency response curve differences. You can modify the curve with a suitable equalizer to imitate any sound that you so desire, however.

cheers:)
The DIY subwoofer at the above link is not even ideal, as the woofer is really suited to a ported enclosure, not a sealed one. While it substantially outperforms the HGS10 and slightly outperforms a DD12(yes, it really does), if you put it in the a proper ported enclosure/system, it will more than likely exceed the performance of even a DD15. Though, the DD series has DSP automatic equalizer set-up to correct for some room issues, so they will sound better in this regard as compared to the DIY subwoofer, unless you set up a parametric equalizer on the DIY subwoofer and do manual correction after taking some measurements.

The measurements at both sites are made using a 2 meter ground plane measurement(equal to 1 meter free-field) in an expansive outside open area, and using standardized methods of distortion calculation. So, they are comparable( but I would assume a +/- 1-2 dB error, due to air pressure, temperature, humidity and other environmental conditions since these measurements were done at different times in different places outside ), but you have to watch some of the graph scales, as the ranges may be different, so you have to visually match the X and Y points on the graphs(the distortion graph is one such example). You also have to match the SPL range graphs with the THD graph SPL ranges to find the actual SPL was achieved with the actual distortion level on the graph. Note that the SPL levels in the graphs are essentially 'anechoic'. In an actual room, a minimum of 10 dB gain can be expected at most bass frequencies, and as well, lower frequency extension is increased in actual rooms.

-Chris
 
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MACCA350

MACCA350

Audioholic Chief
WmAx said:
The DIY subwoofer at the above link is not even ideal, as the woofer is really suited to a ported enclosure, not a sealed one. While it substantially outperforms the HGS10 and slightly outperforms a DD12(yes, it really does), if you put it in the a proper ported enclosure/system, it will more than likely exceed the performance of even a DD15. Though, the DD series has DSP automatic equalizer set-up to correct for some room issues, so they will sound better in this regard as compared to the DIY subwoofer, unless you set up a parametric equalizer on the DIY subwoofer and do manual correction after taking some measurements.

The measurements at both sites are made using a 2 meter ground plane measurement(equal to 1 meter free-field) in an expansive outside open area, and using standardized methods of distortion calculation. So, they are comparable( but I would assume a +/- 1-2 dB error, due to air pressure, temperature, humidity and other environmental conditions since these measurements were done at different times in different places outside ), but you have to watch some of the graph scales, as the ranges may be different, so you have to visually match the X and Y points on the graphs(the distortion graph is one such example). You also have to match the SPL range graphs with the THD graph SPL ranges to find the actual SPL was achieved with the actual distortion level on the graph. Note that the SPL levels in the graphs are essentially 'anechoic'. In an actual room, a minimum of 10 dB gain can be expected at most bass frequencies, and as well, lower frequency extension is increased in actual rooms.

-Chris
Listen to them side by side and I'd bet you'll hear the reason why the Velo's use servo control. Outright SPL is not everything in the world.

When I upgraded to the DD I listened to a few others. One that stood out was a custom built dual 18" sub powered with over 2000WRMS, although it had heaps of SPL the DD walked all over it with its articulation and transient response, and yes I was able to do a side-by-side comparison as the store sold both.

cheers:)
 
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Sheep

Sheep

Audioholic Warlord
A sub that measures well ground plain @ 2m is pretty useless once you put it in a room. The infinity will boost up its low end so it's pretty much flat with room gain, all you will need to do is flatten some of the bumps. The high THD below 30Hz is useless because it would be mostly inaudible. The infinity has the upper hand in groupe delay too.

SheepStar
 
WmAx

WmAx

Audioholic Samurai
MACCA350 said:
Listen to them side by side and I'd bet you'll hear the reason why the Velo's use servo control. Outright SPL is not everything in the world.
The Kappa Perfect unit in question here outperforms[even when installed in sub-optimal sealed enclosure] the DD12 overall in non-linear distortion at any given SPL, which is the single purpose of the servo feedback system.

When I upgraded to the DD I listened to a few others. One that stood out was a custom built dual 18" sub powered with over 2000WRMS, although it had heaps of SPL the DD walked all over it with its articulation and transient response, and yes I was able to do a side-by-side comparison as the store sold both.
For example's sake, one can put the same subwoofer model side-by-side, and each will sound different, due to room interaction physics. As for 'signature', I can take a unit with sufficiently low distortion natural extension, and then apply adjust the frequency response with DSP to 'mimic' any subjective sound signature of 'speed' or 'attack' that one may so desire.

-Chris
 
MACCA350

MACCA350

Audioholic Chief
WmAx said:
The Kappa Perfect unit in question here outperforms[even when installed in sub-optimal sealed enclosure] the DD12 overall in non-linear distortion at any given SPL, which is the single purpose of the servo feedback system.



For example's sake, one can put the same subwoofer model side-by-side, and each will sound different, due to room interaction physics. As for 'signature', I can take a unit with sufficiently low distortion natural extension, and then apply adjust the frequency response with DSP to 'mimic' any subjective sound signature of 'speed' or 'attack' that one may so desire.

-Chris
Transient response is not an effect of eq.

cheers
 
WmAx

WmAx

Audioholic Samurai
I did an over lay of the DD12 and Kappa Perfect 12.1 (sealed) for easy comparison, at both 95dB and 100dB:





It is important to note, that between 20-30 Hz, the DD12 is outputting 2-3 dB less as compared to the Kappa Perfect 12.1, on the 100dB graph, as can be seen by correlating the actual output levels on the baseline measurements made for the power compression measurements at the beginning of the measurement sections on avtalk and dvdplaza, respectively.

-Chris
 
WmAx

WmAx

Audioholic Samurai
MACCA350 said:
Transient response is not an effect of eq.

cheers
Transient response is directly derived from the impulse response, which in turn defines the frequency response(and phase). These are all directly related to each other. Since a loudspeaker is an almost perfect minimum phase device, one can easily modify the response electrically to change the transient response. IN fact, this is a very common trick used in Linkwitz Transform circuits -- a type of equalizer contour filter. But it is jumping to conclusions to assume that one can easily hear the difference in 'transient response' in the first place. You must correlate what you can actually hear with what is measured before assuming a connection. Personally, I have conducted double blind trials of responses with vastly different 'transient responses', but all with about the same corner frequency(30Hz), and the effect is extremely subtle, at best.
 
MACCA350

MACCA350

Audioholic Chief
WmAx said:
Transient response is directly derived from the impulse response, which in turn defines the frequency response(and phase). These are all directly related to each other. Since a loudspeaker is an almost perfect minimum phase device, one can easily modify the response electrically to change the transient response. IN fact, this is a very common trick used in Linkwitz Transform circuits -- a type of equalizer contour filter. But it is jumping to conclusions to assume that one can easily hear the difference in 'transient response' in the first place. You must correlate what you can actually hear with what is measured before assuming a connection. Personally, I have conducted double blind trials of responses with vastly different 'transient responses', but all with about the same corner frequency(30Hz), and the effect is extremely subtle, at best.
Ok I'll put it this way, we played the opening scene to underworld with the rapid machine gun fire. The duel 18 made the rapid fire sound almost muffled(kind of like one starts before the last one finishes), yet the DD played each fire individually and dynamically, very impressive to hear, and eq wont fix that.

cheers
 
WmAx

WmAx

Audioholic Samurai
MACCA350 said:
Ok I'll put it this way, we played the opening scent to underworld with the rapid machine gun fire. The duel 18 made the rapid fire sound almost muffled(kind of like one starts before the last one finishes), yet the DD played each fire individually and dynamically, very impressive to hear, and eq wont fix that.

cheers
I do not know what is occurring with the particular subwoofer to which you refer, since I know nothing about it, and have not measured it, nor have I seen credible extensive 3rd party measurements of the device. With the Kappa Perfect 12.1, however, it can be made to sound however one prefers, due to it's extreme linearity. It appears as if it is a superior driver to the one used in the DD12. I would like to see the DD12 driver without the servo feedback in operation, as I expect distortion to rise substantially in that case.

-Chris
 
MACCA350

MACCA350

Audioholic Chief
WmAx said:
I do not know what is occurring with the particular subwoofer to which you refer, since I know nothing about it, and have not measured it, nor have I seen credible extensive 3rd party measurements of the device. With the Kappa Perfect 12.1, however, it can be made to sound however one prefers, due to it's extreme linearity. It appears as if it is a superior driver to the one used in the DD12. I would like to see the DD12 driver without the servo feedback in operation, as I expect distortion to rise substantially in that case.

-Chris
So what your saying is that two subs that have identical THD and frequency response graphs will sound identical on musical material?
 
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