RBR (Recession Buster Reference)
This design is discontinued now and will not be available again.
See my new C5 and C52 design for replacements. Thanks!!!
Background:
This speaker is a collaboration effort between Clearwave Loudspeaker
Design and Madisound. Madisound will offer this speaker as a kit on
their site. The design was done by Clearwave Loudspeaker Design.
Madisound received a large quantity of the Scan Speak 15S/8531K-01
woofers, and asked me if I could come up with a kit solution to keep
things affordable while still performing at a very high level. The
logical performance to cost ratio tweeter is the excellent SB Acoustics
SB29RDC tweeter to match the Scan Speak's performance at more of a
budget price.
Design Goals:
Develop a speaker that brings increased levels of transparency and use
drivers with low distortion at a Recession Buster price. That means
the crossover must remain simple but perform at a very high level.
Performance:
Some of the highlights of this speaker include a crossover that has no
additional shaping contour networks in the passbands. While we could
have used a much more complicated crossover that utilized a LCR
shaping network to get an extra .5db of flatness in the response, we felt
this wasn't enough gain to substantiate the additional cost. Often a
midbass will have a large diffraction ripple around 800hz-1.5khz.
However, the cabinet diffraction is relatively flat in this critical area
without the need to notch any peaks thanks to the RBR's narrow
profile and side edge chamfer.
We could have also used a conjugate zobel impedance network on the
tweeter, but instead we chose a crossover high enough that the
tweeter's crossover point is far enough away from its Fs. Also,the level
of the tweeter is far enough down at the frequency cutoff so there is
little stress on the tweeter at moderate listening levels. The crossover
point is also low enough to keep the drivers well within their pistonic
range of operation which maximizes the off axis response resulting in
a smooth power response.
We use Clarity Caps, high quality resistors, low DCR coils, and
absolutely no electrolytic components. Only the highest quality parts
are utilized to extract every once of detail from the signal.
The speaker uses about 3.5-4DBs of baffle step compensation, so the
speakers should work in a variety of applications. For the best sound
place them a couple feet away from walls, but feel free to experiment.
This speaker also has a sealed box option if you want to use a
subwoofer. The amazing thing about the Scan Speak woofer used in
this speaker is it's ported bass extension. In room they will extend in
the low 30s! In a sealed box the F3 is going to be around 58hz with a
Qtc of .7 (perfect for integration with most subwoofers).
Frequency Response: 35hz-20k +/- 2.5db Ported
Sensitivity: 82db
Impedance: 8 ohm nominal
This design is discontinued now and will not be available again.
See my new C5 and C52 design for replacements. Thanks!!!
Background:
This speaker is a collaboration effort between Clearwave Loudspeaker
Design and Madisound. Madisound will offer this speaker as a kit on
their site. The design was done by Clearwave Loudspeaker Design.
Madisound received a large quantity of the Scan Speak 15S/8531K-01
woofers, and asked me if I could come up with a kit solution to keep
things affordable while still performing at a very high level. The
logical performance to cost ratio tweeter is the excellent SB Acoustics
SB29RDC tweeter to match the Scan Speak's performance at more of a
budget price.
Design Goals:
Develop a speaker that brings increased levels of transparency and use
drivers with low distortion at a Recession Buster price. That means
the crossover must remain simple but perform at a very high level.
Performance:
Some of the highlights of this speaker include a crossover that has no
additional shaping contour networks in the passbands. While we could
have used a much more complicated crossover that utilized a LCR
shaping network to get an extra .5db of flatness in the response, we felt
this wasn't enough gain to substantiate the additional cost. Often a
midbass will have a large diffraction ripple around 800hz-1.5khz.
However, the cabinet diffraction is relatively flat in this critical area
without the need to notch any peaks thanks to the RBR's narrow
profile and side edge chamfer.
We could have also used a conjugate zobel impedance network on the
tweeter, but instead we chose a crossover high enough that the
tweeter's crossover point is far enough away from its Fs. Also,the level
of the tweeter is far enough down at the frequency cutoff so there is
little stress on the tweeter at moderate listening levels. The crossover
point is also low enough to keep the drivers well within their pistonic
range of operation which maximizes the off axis response resulting in
a smooth power response.
We use Clarity Caps, high quality resistors, low DCR coils, and
absolutely no electrolytic components. Only the highest quality parts
are utilized to extract every once of detail from the signal.
The speaker uses about 3.5-4DBs of baffle step compensation, so the
speakers should work in a variety of applications. For the best sound
place them a couple feet away from walls, but feel free to experiment.
This speaker also has a sealed box option if you want to use a
subwoofer. The amazing thing about the Scan Speak woofer used in
this speaker is it's ported bass extension. In room they will extend in
the low 30s! In a sealed box the F3 is going to be around 58hz with a
Qtc of .7 (perfect for integration with most subwoofers).
Frequency Response: 35hz-20k +/- 2.5db Ported
Sensitivity: 82db
Impedance: 8 ohm nominal
Line all walls with foam and back chamber is filled with acousta stuff. The opening of the
woofer hole is chambered around the basket area to allow the driver to breathe properly.
Don't forget that detail!
woofer hole is chambered around the basket area to allow the driver to breathe properly.
Don't forget that detail!
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Crossover schematic available via
email at this time.
email at this time.