|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
In Reply to: Looking for good 2" compression driver?? posted by j.l.guillebeau@att.net on November 03, 2003 at 16:21:04:
I agree with the other posters that trying to cover 400-20k with a single driver is very difficult, if not impossible, to do. I have always found that when crossing over at around 500Hz that high frequencies will need help in the top octave (even from the favorite vintage drivers). If you decide you can live with a tweeter, then a very good 2" driver is the Selenium D405 (not the Ti). The D405 uses a phenolic diaphragm, and can be used down to 400 Hz, but will need help on the high end above 5-6k. If you want to try and cover the whole range with 1 driver, you will need to go to a titanium diaphragm, which will go higher than the phenolic, although the phenolic has better midrange in my experience. Equalizing will help, although the highs will become quite directional in the top octave using 1 driver.
Follow Ups:
If you use a round horn, then a 2" throat driver will beam above about 6 or 7 kHz. The BMS 4590 tries to get around this by using a concentric driver - a 1" dome inside a 2" ring radiator - but I haven't been able to get a smooth transition between the two radiating elements.So if you want wide high frequency coverage with a 2" throat driver, then you need a horn geometry that addresses the issue. Horns with vanes or lenses were used in the past to get good high frequency coverage (notably by JBL and Altec), and the TAD TH4001 still uses vanes. Multicell horns also gave improved high frequency coverage. Today such designs have largely been supplanted by diffraction horns, for ease of manufacture and (often but not always) lower coloration. As in all things audio, the name of the game is tradeoffs. If you want to use a 2" throat driver to cover the entire upper range, then you must choose between the wider high frequency coverage of a wide-pattern rectangular horn and the lower coloration of a round horn. With 2" throat drivers I lean towards constant-directivity diffraction horns, whereas with 1" throat drivers the high frequency coverage will be wide enough to allow the use of round constant-directivity horns.
There are some generalizations in the above statements, of course.
This post is made possible by the generous support of people like you and our sponsors: