Michael – what’s the system in your avatar? Through innovative engineering eg. Forty years later, and the tradition of excellence continues. Finally, there is an air gap between the cap and the pot structure that is vented in the rear. I will keep the forum posted. The system is still very active at 20 Hz and extremely powerful between 30 Hz and 40 Hz.

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: Pi Speakers ยป JBL AL

There was one goal – to develop the finest drivers possible. With regard to the port, I modelled the box using a 4″ diameter port of 7. I am happy to 1500sl with the higher tuning, the cabs are really quite small. By installing a copper shorting ring around the base of the pole piece, JBL engineers were able to reduce flux modulation, and therefore distortion levels in ferrite motors, to very low levels.

I have the system tuned bwss 27 Hz using a mm vent with generous radii on either end to reduce turbulence noise.

The only problem you will have is leveling out the 150a0l above Hz should you decide to crossover at Hz. Further you’ve also got to contest with cone breakup modes as the frequency rises – this often being increaingly relevant to large area sub woofers.


Nonetheless, the ferrite developments led to an interesting question.

Over the coming months, you will be able to follow our progress here as we work to produce a system worthy of the name – The Project May loudspeaker. Just a last word about stuffing. The cab will be intended for use up to hz, the maximum allowed using my digital setup, and I intend using a ported enclosure. Help needed wiring a transformer to soundcraft main outputs! I wanted JBL sound. I will keep the forum posted.

This is wasted magnetic energy and requires an inordinately strong magnet to ensure reasonable sensitivity. However, Doug was not completely satisfied. None of these constraints were absolute. It was more susceptible to flux modulation caused by voice coil currents and more susceptible to flux loss due to heating. It gives a response that looks very much like a banana. I understand that they are available in Japan seperately, but I cannot find a supplier.

Neodymium magnets have approximately 10 times the magnetic energy by weight as ferrite magnets. However, the principles behind their design trace directly back to those established by Ed May. The ” Project May Blog ” page will provide a log of updates to this section.

Help and Advice needed by newbie

We will be building up a working model over the next month and I will report on progress. It resulted in an Alnico magnet of massive proportions. Should it prove neccessary to boost the low frequencies however, I would experience digital clipping from the processor.


If you have any questions regarding this section of the website, feel free to contact its developer Wardsweb at: Based on that i’d suggest an internal volume of 2. While the AL contains remarkable advances in design, construction and materials, the core principles remain true to those established by Ed May in the development of the LE Testing at a db output level revealed midband distortion to be down 50db, or around 0.

What confuses the issue for me is the use of the Tact RCS2. In January ofJBL Consumer presented the members of this website with an unprecedented opportunity.

Help and Advice needed by newbie | Audio Forums

Ask a Question Want to reply to this thread or ask your own question? Forty years later, and the tradition of excellence continues. There remained the previously identified issue bqss midband loss in output and a more subtle form of flux modulation that was not addressed with the large shorting ring.