Like I said, I am still trying to find the article about multiple speakers in the same cabinet.
Ampeg claims their 4X10's have a usable low frequency of 48Hz, which is way below what any single 10" I have ever seen claims. For their 8X10 they claim 58Hz...well below the 100Hz cited.
Yep, lots of variables here, cabinet design, speaker design...and while realizing that the Bose 901 had an external equalizer box, those little 4"er sounded pretty good to my ears on the low end.
Any thought on Phil Jones and his many small speaker cabinets? Here is a link to his site with an explanation...motor size, etc, etc...but it refers to massing a bunch of small speaker together...I'd be willing to bet that any one of these speakers would not have a TS of below 120Hz....but put a bunch of them together. One would think the same would be true of 12" speakers as well. I would not care to lug around a cabinet like his with 12"er...but I imaging the roof would shake if you did.
http://www.philjonesbass.com/TECH%20INFO/piranha.htm
I will keep looking for the article......and keep learning. Thanks to everyone who shares their knowledge and thoughts..it's what makes this such a remarkable site.
I just went to the Ampeg site, and I saw what you are saying about the frequency response claims. I'm sure they are accurate, but... At what power, at what distance from the cab, and in what room (the term "speaker enclosure" actually refers to all of the constraints between the driver and infinity)? They don't even specify the "1 watt @ 1 meter" control that is
sort of standard for sensitivity rating. Notice the “usable low frequency” rating of 40hz for the 8X10, would you call a -3db to -10db drop in the space of 18hz “usable”? I guess that depends on the “user”. A response graph would be far more telling; even if the ratings are 1 watt @ 1 meter in an anechoic chamber, if the claimed 3db roll off happens abruptly at 100hz or so, which I suspect would be the case, in a studio or live application the effect would be as an SVT actually sounds in real time. This is not bad, it’s not a negative or a design flaw, it’s on purpose. That’s a large part of the reason the SVT is such an iconic bass rig –
tight, focused bottom end. I would imagine the Ampeg 4X10 "LF" is actually smoother into the bottom frequencies than the SVT or the other 4X10 because it's obviously ported. Your ear loses it’s ability to discern directivity of sound at about 100hz or so, from that point down it’s mostly a “feel” thing. It also takes a combination of a ton of power, cone area and excursion (not to mention efficient porting) to physically move enough air for a speaker cabinet to register an even response into the 40-50hz range. I personally love to feel my bass, but it’s an EQ dance to keep the bottom end from becoming omnipresent or “boomy” in the overall tone with my 2X15(s), to maintain definition while still moving a lot of air.
The SVT sounds great IMO, but it
won’t tickle the bottom of your feet like a well designed 2X15 cabinet.
In the late 70’s, I did extensive R&D with multiple small drivers, but mostly in sound reinforcement applications. I was very impressed with the response of the Bose 801 cabinets, but we didn’t limit ourselves with portability. Here’s the problem; small drivers individually don’t move much air. On the positive side, a 4 or 5 inch driver will generally reproduce 15 -16K hz efficiently, up to 18K or so with a
reasonable roll off. (We were interested in live sound reinforcement, not Hi-Fi) effectively eliminating the need for compression drivers. Bass response is directly proportionate with cone area and excursion, if we could control the back side of the drivers into a cohesive wave through creative porting, we could theoretically design a cabinet with no compression drivers, no crossover network, and no radical EQing required. Our goal was to devise a modular system that you could just add cabinets and amps to depending on the venue.
Pretty ambitious for a couple of guys barely in their 20’s, huh?
Well, we ran out of money and motivation
way before we could sell out to some major manufacturer, which was our original business plan. We ended up making some pretty good stage monitors though.
I think the Phil Jones stuff looks pretty interesting. I’ve never even heard the stuff, but because of my experience 30 years ago, I’m sure it would work. Even if the porting
doesn’t get down to 50 hz cleanly, it still would have the potential for a sweet sounding bass rig (SVT?)
In fact, one of my associates approached me last October about getting the Phil Jones franchise locally. At that time I think he actually made a
single output tube 700 watt or so bass amp, using a Russian transmitter tube. As I remember, that was the hot button Dave pushed to try to get me involved, but that might have been
another endeavor he was touting… I’ve got way too many money pits going on already, but we haven’t completely given up on the idea.
I can't find any way to tie this into D120's, I just kept typing, and typing but the segue just never came to me!
