The most efficient 8 inch driver in the world?

Status
Not open for further replies.
Jump to Latest
#44
xrk971 said:
I have to say the spectrum and specs are unbelievable on this driver. It is flat from 20Hz to 20khz and is 102dB (on the graph) so not sure where the 106dB comes from. It appears to have no breakup modes - anyone have experience with these? Looks too good to be true.
Click to expand...

Yeah, that's my first impression too.

It looks like they were measured mounted in a front horn instead of an AES baffle. I can't imagine getting those results without a horn, and some careful mic placement. 😉

These are horn only drivers and that's not a bad thing. They explicitly state that they must be used with horns. However, the conditions of the measurements should also be clearly stated.
 
#45
The JBL 2118 calculates out to a ref eff of 95db and needs a proper low pass crossover below 2Khz. IT does have some bass and Xmax plus is very smooth and flat with a decent lowpass.

JBL used them in several designs with no low pass, a mistake like some of their other designs. JBLs can yack if not treated right.

Scott
 
#46
Greg B said:
Yeah, that's my first impression too.

It looks like they were measured mounted in a front horn instead of an AES baffle. I can't imagine getting those results without a horn, and some careful mic placement. 😉

These are horn only drivers and that's not a bad thing. They explicitly state that they must be used with horns. However, the conditions of the measurements should also be clearly stated.
Click to expand...

I've tried 98dB/w wide ranger (Lowther PM4) and midrange (Focal Audiom 7k) on Oris 150 horn. BD design says it'd be 106dB/w with Lowther.

With simple passive 2way xover with 105dB/w bullet tweeters on top and scanned by ears, it seems the 106dB/w claim is plausible, because the midrange is indeed louder than the treble. Rough RTA measurement at listening position also show a downtilt response.

Interestingly, with both spec'ed as 98dB/w, Lowther is obviously louder than the Focal. So the published datasheets are only for reference. No matter how real they look.
 
#49
Greg B said:
Yeah, that's my first impression too.

It looks like they were measured mounted in a front horn instead of an AES baffle. I can't imagine getting those results without a horn, and some careful mic placement. 😉

These are horn only drivers and that's not a bad thing. They explicitly state that they must be used with horns. However, the conditions of the measurements should also be clearly stated.
Click to expand...

That explains everything. After my experince you cant get miracles from a 8 inch even with lightweight paper membrane and very strong magnet placed on a baffle or in a box.

In the midrange area 300-3000 Hz where i search after the best driver, FOR OPEN BAFFLE USE, it seems that final measured 95-97 dB is the maximum.

Maybee a Feastrex driver could acheive around 100 dB with one of ther heavy and expensive models?

Products
 
#50
superlian said:
That explains everything. After my experince you cant get miracles from a 8 inch even with lightweight paper membrane and very strong magnet placed on a baffle or in a box.

In the midrange area 300-3000 Hz where i search after the best driver, FOR OPEN BAFFLE USE, it seems that final measured 95-97 dB is the maximum.
Click to expand...

Pretty much, at least for FR drivers. The main way to get more efficiency is to raise Fs, and accordingly you'll find some pro midrange drivers at around 100db. However, pro mids may not sound good run very wide band. It's generally assumed they'll cross to a 1" comp driver at 1600 or so. I'm sure there are some exceptions though.

Lowering Qes is another way to raise spl rating, but tends to result in an up tilted response that will only be useful with horns.

How far down are the mids now? Did you take measurements?
 
#52
Greg B said:
Pretty much, at least for FR drivers. The main way to get more efficiency is to raise Fs, and accordingly you'll find some pro midrange drivers at around 100db. However, pro mids may not sound good run very wide band. It's generally assumed they'll cross to a 1" comp driver at 1600 or so. I'm sure there are some exceptions though.

Lowering Qes is another way to raise spl rating, but tends to result in an up tilted response that will only be useful with horns.

How far down are the mids now? Did you take measurements?
Click to expand...

1) Filter: PS, 6 dB high pass
2) Simulation
3) Measurement, ca 130 cm on axis i height with JBL 2119


NTz75sD.jpg
 
#55
superlian said:
Nice, probably possible to get around 100 dB in my setup but it was expensive:

VOXATIV AC-Xp, Full range drive unit - Price per piece

28000 Euro for a pair!!!!
Click to expand...

I agree, they are a bit on the expensive side. I am currently using one of their less expensive drivers (ac1.6) in a TL, but find it to be too bright in the current setup. Working on a new amp..

Where in Norway are you located? I'm in Kongsberg.
 
#59
Beijert said:
How about the audax ht210t0? Very affordable but are they any good? (sounded okay to me btw)

I just can´t get a good link to the specs here
Click to expand...
google found me this link
http://www.google.co.uk/url?sa=t&rc...=6WV9ScEPnEO5IX2g10xt9A&bvm=bv.80642063,d.ZGU

There seems to be some doubt in the specs.
at the beginning it says 40W and 96dB
and later it says 80W and 99dB/W @ 1m
the first results in a maximum of 112 dB@ 1m
the second results in a maximum of 118dB @ 1m

Whereas the next post gives 121dB @ 1m from a double mms, double the Vmax, double BL, nearly double magnetic weight and 140% gap flux.
 
Status
Not open for further replies.
Top Bottom