well, if you put a big inductor (18mH) and start adding power, it will reach that XMax pretty quickly.
And many drivers start to distort way before reaching XMax.
And many drivers start to distort way before reaching XMax.
The cone travel should be exactly the same for a high qts and a low qts driver at the same frequency and spl, right?
I've used two pair of series connected 97db woofers in parallel to a subwoofer plate amp before.
One pair of 15s with a qts of 47, one pair of 12s with a qts of 39.
Worked like a charm for distributed bass from 2 separate panels.(linear X Max on the 15s is only 3mm, on the 12s 8.5mm).
One pair of 15s with a qts of 47, one pair of 12s with a qts of 39.
Worked like a charm for distributed bass from 2 separate panels.(linear X Max on the 15s is only 3mm, on the 12s 8.5mm).
Hi Jonasz
Exactly, no difference between high Q and low Q loudspeakers ability to deliver SPL at a given frequency. It is Sd and Xmax that determines how much SPL at a given frequence you can achieve.
Exactly, no difference between high Q and low Q loudspeakers ability to deliver SPL at a given frequency. It is Sd and Xmax that determines how much SPL at a given frequence you can achieve.
From my own experience lower Q drivers with EQ tend to sound better on open baffle then higer Q drivers. Max output is defined by Sd and Xmax.
When trying to achieve more output adding Sd, as in more drivers, almost always sounds better than adding Xmax. Big woofers with big magnets with lowish moving mass and lots of them, that's the secret sauce in my experience
When trying to achieve more output adding Sd, as in more drivers, almost always sounds better than adding Xmax. Big woofers with big magnets with lowish moving mass and lots of them, that's the secret sauce in my experience
I agree with Sjef. In pure theory there would be no difference... but in actual practice, high Xmax drivers have lower efficiency, more inductance, more mass, and more distortion than a low Xmax driver with a larger Sd. Much better to achieve high output with Sd than with Xmax. It's also less costly.
Real life experiences
I have had very good results with Open Baffles using large light cones no matter the electrical parameters or Xmax of drivers. Very low audible distortion and enough sound pressure to make the listening uncomfortable. Measured sound response very linear to 30 Hz or even lower.
I have had very good results with Open Baffles using large light cones no matter the electrical parameters or Xmax of drivers. Very low audible distortion and enough sound pressure to make the listening uncomfortable. Measured sound response very linear to 30 Hz or even lower.
Troels agrees.
OBL11
"First of all: From a visitor hearing the prototype OBL-11s, I can report that these 15" Eminence DeltaLites beat the crap out of Eminence Alpha 15A, which is often referred to in OB connections as being an ideal driver for this application. This was my expectation and what I had hoped for by choosing a fairly low-Qt driver and applying the equalisation step."
OBL11
"First of all: From a visitor hearing the prototype OBL-11s, I can report that these 15" Eminence DeltaLites beat the crap out of Eminence Alpha 15A, which is often referred to in OB connections as being an ideal driver for this application. This was my expectation and what I had hoped for by choosing a fairly low-Qt driver and applying the equalisation step."
Questions about the Open Baffle concept
I am curious as to why the OB discussions often concerns bass and the extension hereof. To my experience it is quite easy to get reasonable bass performance from OB systems. By resonable i mean linear output from 30 Hz or so and dry precise bass with a sensation of live music. I have had OB's with dual 10", 12" and 15". In dipole or ripole configs and all of them have had basically the same bass in different rooms. I have always used MiniDSP with or without room correction and have tried to make as little use of correction as possible.
BTW. I find it much more interesting to dicsuss how it is possible in OB's to avoid what i call midrange smear. To me it seems that when bass is managed correctly the midrange opens up and becomes much more articulate and precise. To me this is the real benefit of OB's along with the airyness of the treble and the soundstaging as deep and wide - which i percieve as the speakers completely disappearing.
I am curious as to why the OB discussions often concerns bass and the extension hereof. To my experience it is quite easy to get reasonable bass performance from OB systems. By resonable i mean linear output from 30 Hz or so and dry precise bass with a sensation of live music. I have had OB's with dual 10", 12" and 15". In dipole or ripole configs and all of them have had basically the same bass in different rooms. I have always used MiniDSP with or without room correction and have tried to make as little use of correction as possible.
BTW. I find it much more interesting to dicsuss how it is possible in OB's to avoid what i call midrange smear. To me it seems that when bass is managed correctly the midrange opens up and becomes much more articulate and precise. To me this is the real benefit of OB's along with the airyness of the treble and the soundstaging as deep and wide - which i percieve as the speakers completely disappearing.
hedu99 I agree and I've often thought the same thing. I enjoy the open, natural sounding OB bass very much but it's your second paragraph that knocks the nail on the head as far as I'm concerned. Well said.
Interestingly these Deltalites 2515 praised by Troels for bass on a wide baffle is also praised by bushmeister for 150-600Hz baffleless, as well as CharlieLaub also baffleless. Must be a special driver.
Has anybody used Troels' JA8008 in OB? I wonder how much better than my B&C 8PE21 they are.
I believe he moved on to a Caire driver before finally the Faital for bass. I have the Faital but in a closed box. I plan trying it on a large OB some time.
You mean Troels moved to Ciare/Faital? Interesting.
FWIW, I have Faital 18HP1010 bafleless 70-275Hz and like them. I haven't tried other 15-18" though.
I can safely say that I do not know.
However, Briggs recommended side wall placement, a few others have found good results there too, that "could" in effect increase the baffle with infinitely on one side.
The plot thickens.
JE Labs Arkiv (up to 2008): G. A. Briggs - Evolution of the Wharfedale SFB3 Open Baffle
However, Briggs recommended side wall placement, a few others have found good results there too, that "could" in effect increase the baffle with infinitely on one side.
The plot thickens.
JE Labs Arkiv (up to 2008): G. A. Briggs - Evolution of the Wharfedale SFB3 Open Baffle
For test purpose only I have tried to use sidewalls to extend the baffle. This was really good, but not practical in my room
All,
I posted photos & geek gallery of my speaker design projects https://perrymarshall.com/speakers/
Several interesting OB designs here including DSP files.
Perry
I posted photos & geek gallery of my speaker design projects https://perrymarshall.com/speakers/
Several interesting OB designs here including DSP files.
Perry