Why not horns?

Hello Audiokinesis,

I stated the woofer would be directional @ 400hz, not that 400 hz was it's cutoff frequency.

At 400 hz 12db/octave, the dispersion would not be "wide " IMO and Having such a large woofer radiating into the lower midrange would tend to have a lot of coloration's due to it's associated inherent back waves and cabinet reflections emanating thru such a large driver.

For the record , i never told Macrojack that his speaker did not sound good , that was his opinion, he is entitled to it . I'm asking question based on the technical data off the drivers being used which contradict some of his statements. Technically speaking and IMO this speaker would require Eq-ing to have a decent balance....

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Weseixas wrote: "There is no such thing as a fast 15 inch woofer operating @ 400 Hz IMO ! Consider how directional the speaker will be @ 400 Hz and it's large mass ( relative ) with it's accompanying cone coloration ..."

Four hundred hertz is probably more than two octaves below that woofer's upper rolloff frequency, so it will be plenty "fast" enough to do its job. The radiation pattern will be fairly wide at that frequency, and the cone will probably still be pistonic.

Mapman,

Nothing wrong with larger woofers, horses for courses!400hz @ 12db is a bit high for that particular woofer IMO

Bass is pretty much omnidirectional until about 500 Hz. Running even a 15 inch woofer to 400 Hz should be fine.

Please refer to the Chart 3-6 in this manual (kind of a bible for horns)

Weseixas- You have been told repeatedly and politely that you and your friend, IMO, don't know what you are talking about. The JBL L-300 Summit loudspeaker I referenced above crosses from a 15 inch woofer to a horn at 800 HZ. The L-200 does the same at 1200 HZ. If you check another source besides your trusty IMO, you will find numerous examples from other esteemed manufacturers. When you are in this deep, it is usually best to stop digging.

Weseixas, down at 400 Hz, a 15" woofer has a radiation pattern that's approximately 150 degrees wide.

As far as coloration goes, the larger the cone the more difficult it is to get it to behave well. But as long as the behavior isn't too bad, it's possible to correct it or compensate for it in the crossover. On the other hand the smaller the cone the more excursion is required and (in general) the more the voice coil heats up, and therefore the more coloration we get from the motor going non-linear and/or from thermal compression. These types of coloration cannot be corrected in the crossover.

You mentioned coloration from the backwave energy of a large cone. For a given SPL, a large cone and a small cone are moving essentially the same amount of air, so we have the same amount of backwave energy to deal with. A large cone has more area for reflected backwave energy to strike and re-radiate through, but it usually has a larger box which can make better use of damping material to attenuate that backwave energy. I can offer up a link to anecdotal evidence that a good large cone can be low enough in coloration to compete with a good planar.

The main reason I like large cones has to do with radiation pattern control, another topic for another thread.

Having worked with cones large and small for many years (started as an amateur in 1979, turned pro in 2005), in my opinion a good large cone usually has greater performance potential than a good small cone - BUT it is usually a lot harder to work with.

Duke