Guy G wrote:When he talks about the amps, he mentions his cab with EVM speaker, he says it has cylindrical baffles to give it more harmonic content.. wtf is that?
cardboard tubes (ports) in the front baffle board that the speaker is mounted on. As seen in many stereo speaker designs, P.A. and monitors. back is closed I think.
The cabinets are simply T/S designed cabinets that make the speaker "speak" the entire range that it is capable of reproducing. No big thing: plug in the numbers.
All I can say is that I'm 59 and I'm glad he didn't tell me anything I didn't know.
I'm REALLY glad that he reminded me of all of the things that I've forgotten, or blown off, that give the subtleties (magic) that I've neglected.
Maybe it IS a function of age or
, I'm still unsure... oh, wait... that's the Alzheimers.
"Damn... someone older than me... I'm just a baby compared to you (56) "
Yeah, you're still a young buck.
"Damn Dave, you ok there? It almost sounds like you might have...... wait, what were we talking about?"
I might have a brain around here somewhere...
... there it is!
Back to speakers.
High Qts speakers (>.5 or so) are better suited for open baffles. Sometimes they can be used in closed boxes for bass use and guitar but they sound kind of constipated. I personally think that a speaker with a Qts over more than .75 should only be used in an open baffle. Then again, there are a lot of high Qts drivers being used in closed boxes f,or bass, so what do I know?
The old EVM12L speakers had a Qts of less than .3 if I remember correctly and the new ones are at .23. At this low of a Qts closed boxes are "best". .3 - .5 work very well in vented cabinets, with lower Qts requiring smaller boxes. One of the things that I like about Eminence drivers is the wide range of Qts low to high that they have. An alnico 10" has a Qts of 1.9! They have one that will work in about any box imaginable.
rutledj wrote:So would you recommend the celestion 12-65 in this type of box?
I have no idea
Celestion doesn't publish T/S parameters, I can't find them on the 'net and I've never measured one. Without the parameters, box design is just a stab in the dark.
Celestion doesn't publish T/S parameters, I can't find them on the 'net and I've never measured one. Without the parameters, box design is just a stab in the dark.
Sorry.
Dave
I've never seen any guidlines for open back cabinets using T/S parameters anyway. Those guys were interested in ducted ports and closed boxes. The old Altec boxes for VOT and the 604 series broke all the rules. I talked to an old Altec engineer about a set of 604-8Ks that I had where the published numbers are clearly wrong and he said ignore all that. Eight cubic feet for all the 604s. Size the port by ear he said. Sheesh.
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[/quote] I've never seen any guidlines for open back cabinets using T/S parameters anyway. .[/quote]
I assumed the reference to the Reissue G12-65 was about using it in a vented cabinet. Maybe I missed point of his question.
T/S computations were gaining popularity here in the US in the early 70's. I have no doubt that HAD was into all types of research on the entire amp/speaker/cabinet system. Seems he is curious that way. Even his semi-open back cabinets appear to be tuned in some way. Probably by ear due to the size of the opening.
dBe wrote:The old EVM12L speakers had a Qts of less than .3 if I remember correctly and the new ones are at .23. At this low of a Qts closed boxes are "best".
Just wanted to clairify, L.C. uses the old EV (or has in the past) and the box is not "closed" (100%)
rutledj wrote:So would you recommend the celestion 12-65 in this type of box?
I have a clone of the LC/HAD type box used with old EVM12L. Sound is what you would expect. I tried a reissue 12-65 in the same box and the result was more bottom/bass than the 12-65 in other (1x12 open back & 2x12 open back) cabs. FWIW