isobarik sub using peerless drivers

[busterno1]

I was wondering if anyone has any suggestions on a isobarik sub box using two perrless drivers 831857 .
I am using a iso barik to try & get a small box . I already have one driver + plate amp so its just a matter of getting another driver .I will probabley be wiring in paralell as a push pull.
Driver spec
: Free air Common Baffled
Nominal impedance Zn (ohm) 8
Minimum impedance/at freq. Zmin (ohm/Hz) 6.3/124
Maximum impedance Zo (ohm) 46.9
DC resistance Re (ohm) 5.5
Voice coil inductance Le (mH) 2.8
Capacitor in series with 8 ohm
(for impedance compensation) Cc (µF) 24
Resonance Frequency fs (Hz) 24.0
Mechanical Q factor Qms 3.72 3.90
Electrical Q factor Qes 0.49 0.52
Total Q factor Qts 0.44
F (Ratio fs/Qts) F (Hz) 50
Mechanical resistance Rms (Kg/s) 3.25
Moving mass Mms (g) 80.2 Suspension compliance Cms (mm/N) 0.55
Effective cone diameter D (cm) 25.7
Effective piston area Sd (cm²) 520.0
Equivalent volume VAS (ltrs) 210.0
Force factor Bl (N/A) 11.6
Reference voltage sensitivity
Re 2.83V 1m at 124 Hz (Measured)


thanks






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[hifidan]

I built 2 isobarik subs using the 10 inch version 831727. I run them push-pull in a 75 liters box, tuned to 25 hz using a 4 inch port 33 inch in length.
I get an F3 of 22 hz. The only problem is port noise at high volume, otherwise, these subs are highly musical and very satisfying. better for music than HT.
for H/T I built another sub using the Peerless CSX 830452 with a passive radiator in a 1 cu ft sealed box. (See the plans at www.solen.ca ) I use a separate equalizer (ART pro sound) and I get an F3 of 27 hz but no port noise and a lot more db for HT, Also good for music.

[ODougbo]

Old thread..... did you every complete the project, I’m thinking about doing the same project.

Originally Posted by busterno1

I was wondering if anyone has any suggestions on a isobarik sub box using two perrless drivers 831857 .
I am using a iso barik to try & get a small box . I already have one driver + plate amp so its just a matter of getting another driver .I will probabley be wiring in paralell as a push pull.
Driver spec
: Free air Common Baffled
Nominal impedance Zn (ohm) 8
Minimum impedance/at freq. Zmin (ohm/Hz) 6.3/124
Maximum impedance Zo (ohm) 46.9
DC resistance Re (ohm) 5.5
Voice coil inductance Le (mH) 2.8
Capacitor in series with 8 ohm
(for impedance compensation) Cc (µF) 24
Resonance Frequency fs (Hz) 24.0
Mechanical Q factor Qms 3.72 3.90
Electrical Q factor Qes 0.49 0.52
Total Q factor Qts 0.44
F (Ratio fs/Qts) F (Hz) 50
Mechanical resistance Rms (Kg/s) 3.25
Moving mass Mms (g) 80.2 Suspension compliance Cms (mm/N) 0.55
Effective cone diameter D (cm) 25.7
Effective piston area Sd (cm²) 520.0
Equivalent volume VAS (ltrs) 210.0
Force factor Bl (N/A) 11.6
Reference voltage sensitivity
Re 2.83V 1m at 124 Hz (Measured)


thanks






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[TheBaronGroog]

Odougbo, have you got the TS parameters for your drivers? I can model it in BBpro on a quiet day at work

[ODougbo]

Woops, sorry so slow and thanks!! Very interested in re-visiting these. I have 4 on the shelf, all in a-ok shape. There’s a fellow on ebay that has a number of them also.

http://www.d-s-t.com.au/data/Peerless/831857.pdf


Parameters: Free air Common Baffled
Nominal impedance Zn (ohm) 8
Minimum impedance/at freq. Zmin (ohm/Hz) 6.3/124
Maximum impedance Zo (ohm) 46.9
DC resistance Re (ohm) 5.5
Voice coil inductance Le (mH) 2.8
Capacitor in series with 8 ohm
(for impedance compensation) Cc (μF) 24
Resonance Frequency fs (Hz) 24.0 22.9
Mechanical Q factor Qms 3.72 3.90
Electrical Q factor Qes 0.49 0.52
Total Q factor Qts 0.44 0.46
F (Ratio fs/Qts) F (Hz) 50
Mechanical resistance Rms (Kg/s) 3.25
Moving mass Mms (g) 80.2 88.2
Suspension compliance Cms (mm/N) 0.55
Effective cone diameter D (cm) 25.7
Effective piston area Sd (cm²) 520.0
Equivalent volume VAS (ltrs) 210.0
Force factor Bl (N/A) 11.6
Reference voltage sensitivity
Re 2.83V 1m at 124 Hz (Measured) (dB) 89.3
Voice coil diameter d (mm) 39
Voice coil length h (mm) 26.0
Voice coil layers n 4
Flux density in gap B (T) 0.99
Total useful flux (mWb) 1.52
Height of the gap hg (mm) 8
Diameter of magnet dm (mm) 134
Height of magnet hm (mm) 22
Weight of magnet (kg) 1.28
Power handling:
Long term Max System Power (IEC) (W) 220
Max linear SPL (rms) / by power (dB/W) 110/170

PORTED - 80 - 160 L
Because of the high VAS (210 L), a ported box for this speaker becomes rather
large (120L or 4ft³ for F =25Hz). However, exceptionally low undistorted bass
is possible from such a design. The simple mounting structure and shallow
10cm depth enable this driver to be used in many designs like isobaric….,

[ODougbo]

Oh btw, I think the mag to front looks better (vs. clamshell), I get tired of looking at the back of a speaker pretty quickly. Here’s a pic of what I have in mind, the cool trick is the tuning, that “L” shaped baffle board, slides up and down, to fine tune the porting, then the final assembly, glue up.

Thanks for help and info!!

[ODougbo]

I pulled the 12” peerless woofers out today (4), and cleaned them up, they look fine. I also ran some box configurations on Perfect Box, even with isobaric mounting 2, the box would be large.

I thought these woofers might be good in a tri or quad vented enclosure; leaning to toward 4, front to mag: 1,2,3,4. Peerless recommends a 160 liter cab, so that would be cut down to 40 (about 1.5 cf). The tunnel alone would be in the 15” round x 10.5” tall range, approximately another cubic foot.

One advantage to using 4 speakers would be wiring, 2 speakers parallel = 3ohm load(s), so I could use a heavy stereo amp.

The woofers are “light” only 7 ½ lbs each, a 30lb “motor” might be interesting.

Thanks for any advise you may want to share. Btw, I do plan on using these in a HT.

Originally Posted by TheBaronGroog

Odougbo, have you got the TS parameters for your drivers? I can model it in BBpro on a quiet day at work