Good (vintage?) drivers for BiB's? Which should I get?

[Scottmoose]

Goodness knows, & that's a fact. Depends on how it was measured. if with a low voltage driver Q can appear un-naturally hige. I gether there are advantages to using a low votalge driver for meausrements, but what they are, I've no idea. Your oversized cabs could actually work better if the Q is as high as that, which I'd frankly take with a large pinch of salt. Still, it's not unknown for manufacturers claims to be laughably innacurate: look at Lowther.

 

[planet10]

What I have seen is the SPH155X which claims 0.5 QTS. Measured 0.8 in reality!! Question arise then, how much difference will it make when listening, not looking at a graph?

Also keep in mind that the kit you use can produce different T/S parameters. If you are using a computer drive system like i am measured Qt will be higher than if, for instance, you are using a manual system with 1 V drive.

The difference you are indicating for this driver is larger than usually attributable to different measuring kit thou.

You have to understand that T/S are not really a single number, but a set of curves that are a function of drive voltage. One has to keep this in mind when designing boxes.

dave

 

[planet10]

Goodness knows, & that's a fact. Depends on how it was measured. if with a low voltage driver Q can appear un-naturally hige. I gether there are advantages to using a low votalge driver for meausrements, but what they are, I've no idea.

The advantages are ease & speed (ie 10 drivers in 1/2 hr instead of 1 or 2, and much less set-up time). And the resulting numbers are perfectly valid for that drive voltage. With a fairly efficient speaker they are on the order of background listening levels.

dave

 

[peterbrorsson]

Ok, I think I understand A little bit of topic. Have been in contact with Thorsten Weber at Boxen-baustelle a while ago, concerning Monacors. Sound impressions are certainly personal, but he claims that SPH155X sounds better than SPH60X. A fraction more mids on the former. Think I'm going to try it for a friend of mine. It will be my third BIB's then. Hmm, I'll have to stop work if this keeps up

Cheers

 

[Geoff H]

Originally posted by peterbrorsson
"What I have seen is the SPH155X which claims 0.5 QTS. Measured 0.8 in reality!! Question arise then, how much difference will it make when listening, not looking at a graph?"

In the final setup, ie amplifier, driver, and enclosure, the higher Q system will be more efficient, have a faster transient response, and less ringing.

Your question is a very important one. A pity too many people overlook it. After all, don't we spend more time listening to music than gazing at graphs and figures?

Good luck with the 3rd BIB.

 

[Enochrome]

I have just made reflex boxes for my Stephen Trusonic FR80's. The dimensions of the boxes are to spec of the original one they offered with the driver. I have put 2" wide x 6" long port in. I have stuffed it pretty good but not overly so. When I used my First Watt j2 + TVC the effiency is not that great, only a little better than my Revel M20's. Is it that I am doing something wrong or that the efficiency of the driver drops over time? It also sounds like the sound is coming out of a tin can; very recessed mid-range with little midbass.

Any insight?