Peerless 830847 XXLS12
Peerless 830847 at EssentialAudio - $309 AUD including GST (16th February 2009)
Peerless 830847 at Speakerbits - $336.36 AUD excluding GST (16th February 2009)Double Voice Coils 8ohm + 8ohm in parallel
|Z - Nominal Impedance||4 ohm|
|Pe - Power Handling||350W (175 continuous)|
|SPL - Sensitivity||86.9 dB/watt@1m|
|Re - Voice coil resistance||2.5 ohm|
|Fs - Resonant frequency||21.8 hz|
|Qms - Mechanical Q||10.24|
|Qes - Electrical Q||0.37|
|Qts - Total Q||0.36|
|Vas - Equivalent volume||144.2 litre|
|Xmax - Maximum excursion||12.5 mm|
|Sd - Cone Area||466 sq cm|
|EBP - Efficiency Bandwidth Product||57 - All rounder|
Driver parameter file for this driver for WinISD Pro ver 0.50a7
|Box size||Tuning frequency||Port details|
|My design||70litre box||26hz tuning||Two 102mm ports 947mm long|
|My design||54 litres sealed|
Project files for WinISD Pro ver 0.50a7
Not bad as you would expect of a 12 inch driver with 350w applied. Excursion limits prevented an EBS tune which would have been flatter and yielded more @ 25hz
Since the EBP value suggests a sealed design, I have modelled it in red. Excursion limits dictate using the 240W amp incl boost
Sealed design shown in red
Port air velocity
Most people would probably go for the sealed design which doesn't require the filter.
The ported design gives more, but requires a larger amp, a high pass filter and the need to use long ports.
Peerless designs use passive radiators to overcome the port problem.
Calculated with Flare-it
I would recommend a 13mm routed flare.
The intake could be flange mounted with a 13mm routed flare or you could fit a donut ring.
Depending on the flaring options, you'll need to adjust the physical length so that the effective length is as shown in the designs.
The port flares page has a section on calculating effective length as well as some information on availability of commercial flares.