Vertical Mounting of Sub1500
Quote:
Originally Posted by Giskard
I'm not going to comment on that since you've already built your subs, but here's what I got for numbers:
Thanks very much for posting your numbers on sag. Based solely on that data, it seems that the Sub1500 would be OK for vertical mounting (i.e. the sag is less than 5% of Xmax). Nevertheless, since the cone is so heavy (with Mms at 300 gm), I understand that you would not recommend a downfiring application. Could you comment on this further? What upper limit should be put on Mms for a speaker to be recommended for this configuration? Does anyone know of any literature on the long-term effects of vertical mounting?
I really like the performance of the Sub1500 and I would hate to damage it, over time, due to vertical mounting. A frank opinion would be really appreciated. (I'll re-build/re-configure my subs if necessary!)
Vertical Mounting of the Sub1500
Quote:
Originally Posted by Giskard
I'll get a definitive answer for you sometime next week.
Have you heard from any of your JBL contacts regarding the suitability of the Sub1500 for vertical mounting? I would love to hear what someome like Doug Button has to say on the subject.
I have been unable to find any literature or papers on vertical mounting, except for the often repeated "rule of thumb" that the sag must not exceed 5% of Xmax. (The Sub1500 meets this requirement.)
However, I did dig up some interesting details on the B&O BeoLab 5 speaker system. It uses a vertically mounted 15" driver, in a 1 cu ft (28 L) sealed box, and it is driven by an "equalized" 1000 w amplifier. The only other info that I could find out about the transducer is that its Xmax is 21 mm, and the resonance in the box is 60 Hz. This sounds a lot like the original Revel Sub15 application that the Sub1500 was designed for. In fact, I ran the Sub1500 parameters with a 1 cu ft sealed box and got a resonance of exactly 60 Hz! So, the B&O 15" driver must be very similar to the Sub1500.
Therefore, the above information begs the question - did the B&O engineers know what they were doing when they vertically mounted their driver? Can we use this design as evidence that the Sub1500 would be OK in this type of application? Perhaps, this is a loaded question to ask on a JBL forum! Can we get an opinion from the JBL engineers? Maybe B&O and JBL could "slug it out" at the next AES conference!
Regards,
Linear