Here are my SF measurements.
The top one shows more cavity effect from nearby drivers. The lower shows more baffle losses. Due to their locations on the baffle.
A little about how the were measured. They're about 4m from any reflection. The baffle is 250 x 665mm. They were high passed at 100hz. That was about 5watts. Ignore the tweeter measurement in the graph.
I can show the raw if someone would like. The raw is very close to the gated.
Ok, From this you can see how nasty the 3khz and up region is. I have a love hate relationship with this woofer. IMO, it only does one thing. 80 to 1.5khz with better than average sensitivity in a small for 8" box. That's exactly how I use it. Now, I'm no good box designer. If a TL or something can coax more bass from it, all the power to you. But nothing fixes that HF garbage. The little bit of extra bass isn't worth the extra cab volume to go ported IMO.
If anyone wants more info on this woofer, in the summer I plan to:
- 180degree off axis;
- 2.83V SPL
- Ground plane for 25L sealed bass response;
- 80hz high pass power compression; and
- Full range power compression.
Will do in that order in case I pop a woofer. Plan to feed it about 100 watts. Starting at 2.83V doing power doubling.
The top one shows more cavity effect from nearby drivers. The lower shows more baffle losses. Due to their locations on the baffle.
A little about how the were measured. They're about 4m from any reflection. The baffle is 250 x 665mm. They were high passed at 100hz. That was about 5watts. Ignore the tweeter measurement in the graph.
I can show the raw if someone would like. The raw is very close to the gated.
Ok, From this you can see how nasty the 3khz and up region is. I have a love hate relationship with this woofer. IMO, it only does one thing. 80 to 1.5khz with better than average sensitivity in a small for 8" box. That's exactly how I use it. Now, I'm no good box designer. If a TL or something can coax more bass from it, all the power to you. But nothing fixes that HF garbage. The little bit of extra bass isn't worth the extra cab volume to go ported IMO.
If anyone wants more info on this woofer, in the summer I plan to:
- 180degree off axis;
- 2.83V SPL
- Ground plane for 25L sealed bass response;
- 80hz high pass power compression; and
- Full range power compression.
Will do in that order in case I pop a woofer. Plan to feed it about 100 watts. Starting at 2.83V doing power doubling.
>>> How do you get 94 dB out of a 91 dB driver?
Stick em in corners like Audio Note does and measure that way. Funny to see the measurement technique in the photo above. That's a large listening space.
After many years of wrestling with how to get the highest efficiency from a given driver (or just finding good high efficiency drivers) I've come to realize the tradeoffs and accept them. Anything around 90db per watt plays loud enough for me using an extremely modest low powered T-amp. 95db+ and you can get very loud with the same modest amp. The Eminence Beta12lta is rated at 97db and it goes very loud with very little. It's not perfect but it's a fun listen for sure! The Fostex drivers over 90db all play loudly with little power and even drivers with less efficiency (TB and perhaps Alpair - tho i never had the pleasure of hearing them) fill a room with sound with little power too. My personal cutoff is 87db.
If you want small boxes, make small boxes. You can always enhance with a powered sub(s). If you do not want a sub but want that full range driver magic then you must build larger, more complicated cabinets. They have their own set of unique sonic advantages. This way you get the full bass with only two boxes in your listening room and an extra bit of jump factor to keep your toes tapping and your friends envious.
Unless you go open baffle... lol... which is yet another way to enjoy full range drivers.
Zilla
Stick em in corners like Audio Note does and measure that way. Funny to see the measurement technique in the photo above. That's a large listening space.
After many years of wrestling with how to get the highest efficiency from a given driver (or just finding good high efficiency drivers) I've come to realize the tradeoffs and accept them. Anything around 90db per watt plays loud enough for me using an extremely modest low powered T-amp. 95db+ and you can get very loud with the same modest amp. The Eminence Beta12lta is rated at 97db and it goes very loud with very little. It's not perfect but it's a fun listen for sure! The Fostex drivers over 90db all play loudly with little power and even drivers with less efficiency (TB and perhaps Alpair - tho i never had the pleasure of hearing them) fill a room with sound with little power too. My personal cutoff is 87db.
If you want small boxes, make small boxes. You can always enhance with a powered sub(s). If you do not want a sub but want that full range driver magic then you must build larger, more complicated cabinets. They have their own set of unique sonic advantages. This way you get the full bass with only two boxes in your listening room and an extra bit of jump factor to keep your toes tapping and your friends envious.
Unless you go open baffle... lol... which is yet another way to enjoy full range drivers.
Zilla
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That still does not increase the efficiency when measured above the 2pi>4pi corner. Any room gain added does not increase efficiency unless you are cheating.
dave
>>> Any room gain added does not increase efficiency unless you are cheating.
We both know they ARE cheating.
The drivers i've listened to in my listening room rated from 91 to 95db all sounded pretty much the same as far as efficiency goes. This surprised me (and was a bit disappointing). Pioneer B20 rated at 91, Fostex 127e rated at 91, TB 1808 rated at 93, Fostex 168s rated at 94, Fostex 165k rated at 95... They all sounded loud enough with a cheap T-amp and an expensive (for me anyways) el34 tube amp.
The drivers i have on hand rated at about 87db all sounded less efficient than the above. They consist mostly of various TBs that are three and four inch diameter. But they also performed perfectly fine with the same amps. I am not wanting for efficiency... yet i still seek highly efficient drivers because I feel they offer a bit more jump and excitement.
We both know they ARE cheating.
The drivers i've listened to in my listening room rated from 91 to 95db all sounded pretty much the same as far as efficiency goes. This surprised me (and was a bit disappointing). Pioneer B20 rated at 91, Fostex 127e rated at 91, TB 1808 rated at 93, Fostex 168s rated at 94, Fostex 165k rated at 95... They all sounded loud enough with a cheap T-amp and an expensive (for me anyways) el34 tube amp.
The drivers i have on hand rated at about 87db all sounded less efficient than the above. They consist mostly of various TBs that are three and four inch diameter. But they also performed perfectly fine with the same amps. I am not wanting for efficiency... yet i still seek highly efficient drivers because I feel they offer a bit more jump and excitement.
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