I am very interested in using Peerless GBS series low-profile woofer in a simple two-way system. Two 5.25" model (GBS-135F25AL02-04) were purchased. Tectonic Element TEBM35C10-4 BMR driver is chosen to handle mid-high frequencies. Both drivers are available from PE. Since the BMR is a full-range driver, the crossover point can be freely select to avoid highly sensitive audio band 1 kHz to 5 kHz. Data sheet shows the BMR has wide directive extending to 15 kHz.
I will study sealed box and vented box in simulation. LEAP 5 software will be used for box as well as crossover design. In order to get better simulation results, I use LEAP LTD model (http://www.diyaudio.com/forums/equipment-tools/273686-clio-pocket-17.html#post4955200) instead of conventional TS based on small-signal model. The woofer was therefore measured for various signal levels. Obtained text files of driver voltage and impedance were processed by LEAP to obtain LTD mode. I also used CLIO Pocket to perform small-signal TS measurement (delta mass method) for comparison. Data of the two models are shown below. Xcoil (12.6 mm) was based on published gap height and max linear excursion.
I will study sealed box and vented box in simulation. LEAP 5 software will be used for box as well as crossover design. In order to get better simulation results, I use LEAP LTD model (http://www.diyaudio.com/forums/equipment-tools/273686-clio-pocket-17.html#post4955200) instead of conventional TS based on small-signal model. The woofer was therefore measured for various signal levels. Obtained text files of driver voltage and impedance were processed by LEAP to obtain LTD mode. I also used CLIO Pocket to perform small-signal TS measurement (delta mass method) for comparison. Data of the two models are shown below. Xcoil (12.6 mm) was based on published gap height and max linear excursion.
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interesting project.
i have purchased the 3" BMR to use with a 8" midwoofer
are you thinking MTM? crossover point?
i have purchased the 3" BMR to use with a 8" midwoofer
are you thinking MTM? crossover point?
It'd be interesting to see distortion tests of the peerless, looks like it would make a great mid, but calling it a woofer is a bit of a stretch, won't get much below ~ 70 Hz...
I will make simple TM layout. The crossover point is expected to be set between 200 to 500 Hz. The system may eventually be an active 2-way with active xover and bi-amp.
I will evaluate both sealed and vented configuration. Deep bass is not the target for this project. The 10" model may be worth for consideration.
This BMR is 80 dB/1W/1m. The project will eventually be an active speaker. Leveling matching should not be an issue.
Active will work! I have two designs in progress using the 46mm one. These things can are pretty unique in dispersion, about the same as 30-35mm dome tweeter. I imagine the 35mm one is even better.
An advantage of GBS low-profile driver is that its acoustic center will be nearly on the same plane as the tweeter (BMR). I will also test it with TEBM46C20N, the 46 mm one.
what makes you think it will not be good as a woofer?
it's capable of ~16mm peak to peak displacement.
broadly speaking it should perform better than the ScanSpeak 15W/8434G00
it has a smaller Vas and more motor strength.
re:'what makes you think it will not be good as a woofer?', IIRC, I did a Unibox sim which indicated that, must have done something wrong, I did one again & it looks good in 14L tuned to 49Hz for an F3 of ~40. Still like to see a distortion test though...
the low frequency distortion will be mainly governed by the BL linearity and inductance, which are not particularly, related to the 'slim' aspect of the design.
if you benchmark it against a lot of other 5" woofers/midwoofers you'd be suprised to find the distortion is lower than a lot of non-slim drivers.
it's made slim by re-arranging how the parts interact, not by compromising their ability for excursion.
if you benchmark it against a lot of other 5" woofers/midwoofers you'd be suprised to find the distortion is lower than a lot of non-slim drivers.
it's made slim by re-arranging how the parts interact, not by compromising their ability for excursion.
LTD mode of LEAP5 is really helpful to provide useful nonlinearity information in a very low-cost fashion compared to Klippel. The figure below shows BL of the GSB driver driven by 10 W. Corresponding Xm is shown in the second figure. The peak RMS excursion is 3.64 mm at the ~50 Hz. BL at that point is 3.79. The BL at higher frequencies is 4.48. BL drops about 15 % under the driving condition. Similarly, compliance variation is also available.
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