Something stirs in the Undergrowth

Dedicated to those large boxes at one end of the room
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Ali Tait
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#1321

Post by Ali Tait »

That is a LOT of overtime!
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rowuk
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#1322 Blowhards beware

Post by rowuk »

You feel it more than hear it. It really does work and is much more compact than a woofer moving a comparable amount of air. I am not sure about aligning it for phase however.

The pitch of the propeller changes with the music. If there was DC in the output, it would just blow. The upper range is limited by the air resistance on the propeller vanes. There is only so much horsepower available. The propeller rotates at a constant 1200 RPM.
pre65 wrote:
Ali Tait wrote:I'd expect air con for 12k! :shock:
Nearer to 25K (US dollars) for the package. :shock:
Whenever I feel blue, I start breathing again.
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Paul Barker
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#1323

Post by Paul Barker »

Just like the old Hercules military aeroplane. Fixed prop speed, changing pitch.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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IslandPink
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#1324

Post by IslandPink »

Guys - by all means have a thread about fan-based subwoofers :D

Meanwhile, latest build from Troelsgraven :
http://www.troelsgravesen.dk/ScanSpeak-3W-Discovery.htm
Comment "What the ScanSpeak 22W/8534G00 bass driver has the SEAS CA22RNX doesn't, is a higher mechanical Q due to the fiber glass voice coil former, delivering better low-level detail and transient response"
ScanSpeak 22W/8534G00 : Rms = 1.05
"Once you find out ... the Circumstances ; then you can go out"
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IslandPink
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#1325

Post by IslandPink »

I promise I'll eventually stop going-on about Rms, but not before I've updated the list once more. Check out the values on some of the smaller Fostex drivers at the top !
JamesD was toying with the idea of using an array of smaller ( 4" drivers as a midrange option for an updated 'Quasar' , if he could get around the lobing problems . Maybe worth pursuing ?...( but not me ! )

I've also included a few power handling values ; there's a fairly good trend of increasing power handling going with increasing Rms .

Anyway, as I've said along the way, my interest in this parameter is mainly connected with the rendition of low-level detail, microdynamics and tone at low signal level . Certainly there are some difficulties ( F.R., Xmax, Qts ) with some ( not all ) of the low Rms ones on the list, and their application will require careful choice and the usual modelling depending on the anticipated loading method.

Fostex FE108EZ : 0.167 ( 8W rms )
Fostex FE126En : 0.30
Supravox 215-2000 Alnico : 0.40 ( 20W rms )
Fostex FE103En : 0.48 ( 15W rms )
SABA Greencone 'Permadyn 19-200-5298-U8' : 0.57
Fostex FE208Ez : 0.59 ( 40W rms )
Fostex FE206E : 0.66
Fostex FF165 : 0.68
Supravox 285GMF : 0.71 ( 70W rms )
AER Mk.1 : 0.77
Lowther PM6A : 0.90
Supravox 285-2000 Alnico : 0.93
ScanSpeak 22W/8534G00 : 1.05
GPA 416-8B Alnico s/n 0229 (G Dahl) : 1.09 ( 75W rms )
GPA 515-16C Alnico s/n 0202 (G Dahl) : 1.09
Supravox 400-2000 Alnico : 1.12
Supravox 400GMF : 1.14 ( 120W rms )
GPA 515-16C Alnico s/n 0201 (G Dahl) : 1.23
Lowther PM2A : 1.33
Altec 416B ( manufacturer data ) : 1.36
Altec 414A : 1.38
Faital Pro 12PR300A : 1.38 ( 300W rms )
Supravox 400GMF Pro : 1.40
Altec 414B (G Pimm) : 1.53
Eminence Kappalite 3012HO (drivervault) : 1.53 ( 400W rms )
Eminence Beta 15 : 1.63
Beyma 12MW/ND : 1.74
PrecisionDevices PD-N12MH25 : 1.78
Eminence Kappalite 3012HO (manufacturer) : 1.83
Fostex FF225K : 1.87 ( 34W rms )
Vifa P13WH-00-08 : 2.05
Beyma 12B100 : 2.16
B&C 12PE32 : 2.20
Monacor SP30/200 NEO : 2.34
Eminence Kappalite 3012LF : 2.43 ( 450W rms )
B&C 8PE21: 2.55
Jensen P12N : 2.6
RCF MB12N251 : 2.85
Acoustic Elegance TD-15M : 3.0
18Sound 10W400 : 3.22 ( 280W rms )
B&C 8NDL51 (Neo) : 3.30
Acoustic Elegance TD-12M (drivervault) : 3.31
Fane Colossus 12BMN : 3.32
Fane Colossus 12BM : 3.35
Fane Colossus 12BM : 3.35
Fane 15BXN : 3.45
Eminence DeltaLite II 2512 : 3.64 ( 250W rms )
Fane Sovereign 12-350N : 3.99
B&C 12hpl64 : 4.16
Eminence Deltalite II 2515 : 4.26
Fane Studio 8M : 4.38 ( 250W rms )
JBL 2226H/J : 4.93
Fane Colossus 12MBN : 4.94
Fane 18XBN : 6.22 ( 1000W rms )
B&C 15NW76 : 6.38
Fane Colossus 12MB : 9.95 ( 500W rms )


Sources: Manufacturer data, Gary Dahl, Gary Pimm, Rowuk and Drivervault
"Once you find out ... the Circumstances ; then you can go out"
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IslandPink
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#1326

Post by IslandPink »

Just received my copy of Dick Olsher's 'Basszilla' plans and crossover . It's nice background , to see how he used the FE208Ez for instance. It's quite a quite a nice big booklet , with about a dozen designs altogether including the history and the Lowther variants . Well worth $20 .
"Once you find out ... the Circumstances ; then you can go out"
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IslandPink
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#1327 Interim

Post by IslandPink »

OK... I've brewing up a plan . The plan is for an 'Interim' speaker .
I'm getting frustrated that there's still a lot to do with the four-channel finished system. One big hurdle is to build the second example of the 2/3-channel SE amp ; I know how long that took last year.
So, having not had any proper system with which to listen to music in that last 3 years ( at least ) , I think a step towards the full system is required.

Having been looking at the FE208Ez as a midrange option, and now having the plans & crossovers Dick Olsher used for the 'Basszilla' , it seems like a small step to bring downstairs the Aurum Cantus G3 ribbons, get some crossover components, and build a variant of the Basszilla 'Platinum Mk.2' . I know Jon Noble is still very positive about the Basszillas , so it should be a good reference point .
This way I can have a stereo pair of nice-sounding speakers in the room, but continue to 'fill in the gaps' with some of the other issues like crossover/integration for the bass/mids , OB design ( wings ) for bass , phono amp upgrade, GK-71 output stages on the main amp etc .

So it will be the basszilla mids & treble, supplied from valve amp ( with 1st-order high-pass ~ 150Hz ) with passive crossover parts for the FE208Ez and G3 cross ; then OB bass using the Deltalight 2515's and the special bass pre-amp ( shelf/low-pass )-into F4 set-up that I'm currently working on .

Just bought a few Visaton coils from EBay and ordered some 3.9uF caps ( Mundorf ) from HiFiCollective.

If I can get these speaks done I can also keep up on my homework from Mr. Dave the Bass .
"Once you find out ... the Circumstances ; then you can go out"
waveguide
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#1328 Re: Interim

Post by waveguide »

IslandPink wrote:OK... I've brewing up a plan . The plan is for an 'Interim' speaker .
I'm getting frustrated that there's still a lot to do with the four-channel finished system. One big hurdle is to build the second example of the 2/3-channel SE amp ; I know how long that took last year.
So, having not had any proper system with which to listen to music in that last 3 years ( at least ) , I think a step towards the full system is required.

Having been looking at the FE208Ez as a midrange option, and now having the plans & crossovers Dick Olsher used for the 'Basszilla' , it seems like a small step to bring downstairs the Aurum Cantus G3 ribbons, get some crossover components, and build a variant of the Basszilla 'Platinum Mk.2' . I know Jon Noble is still very positive about the Basszillas , so it should be a good reference point .
This way I can have a stereo pair of nice-sounding speakers in the room, but continue to 'fill in the gaps' with some of the other issues like crossover/integration for the bass/mids , OB design ( wings ) for bass , phono amp upgrade, GK-71 output stages on the main amp etc .

So it will be the basszilla mids & treble, supplied from valve amp ( with 1st-order high-pass ~ 150Hz ) with passive crossover parts for the FE208Ez and G3 cross ; then OB bass using the Deltalight 2515's and the special bass pre-amp ( shelf/low-pass )-into F4 set-up that I'm currently working on .

Just bought a few Visaton coils from EBay and ordered some 3.9uF caps ( Mundorf ) from HiFiCollective.

If I can get these speaks done I can also keep up on my homework from Mr. Dave the Bass .
This looks like a good direction for getting excellent midrange/treble at usable sound levels. The FE208Ez does not seem to appear available.

Is there some inpublilshed problem with the very low Cms and how it is derived with very light structurally diaphragm but this probably does not matter for treble as you would use the G3 to top it out
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IslandPink
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#1329 Re: Interim

Post by IslandPink »

waveguide wrote: This looks like a good direction for getting excellent midrange/treble at usable sound levels. The FE208Ez does not seem to appear available.
Is there some inpublilshed problem with the very low Cms and how it is derived with very light structurally diaphragm but this probably does not matter for treble as you would use the G3 to top it out
If I could find a shortcut for the 'Sigma' character, I could write the name of that speaker properly ! ( FE208E-sigma ) .
I've heard them at Owston meets, but not recently .
Dick Olsher's scheme rolls-off the output from 2.5k which knocks the 4kHz peak down and takes the untidy high treble out of the mix , letting the G2Si ( in his case ) take over.
"Once you find out ... the Circumstances ; then you can go out"
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Paul Barker
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#1330 Re: Interim

Post by Paul Barker »

IslandPink wrote: If I could find a shortcut for the 'Sigma' character, I could write the name of that speaker properly ! ( FE208E-sigma ) ..
Cut and paste this Σ into a word file.

I really loved the 108Σ when I heard Steve's first metronomes. Have enjoyed both OB's I used them in.

Has some colouration, but a nice quality of sound. For me top end is sufficient without any help..

Just can't get OB's passed the Matriarch.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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IslandPink
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#1331

Post by IslandPink »

Thanks .
Yes, good unit .. but not much headroom . Maybe the combo of 208eΣ and ribbon that Dick has used can give something like a scaled-up version of the same sound .. we will see.

Meanwhile : Fertin 20ex model 7 ( at 12.5v) : Rms = 0.225
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chris661
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#1332

Post by chris661 »

Could you use the 208ES (S=sigma for now), plus the 108ES crossed at, say, 1kHz, with maybe a ribbon above that?

Nice little 3-way system, but by keeping the mid and bass drivers similar, you'll maintain a similar tonality. Cross the ribbon up high and I think you'd be on to something.

Chris
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Paul Barker
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#1333

Post by Paul Barker »

What he said.

You can borrow my 108,s to check the concept. But they aren't for sale. Too good to sell.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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IslandPink
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#1334

Post by IslandPink »

You could use that , yes, would be interesting . But that would be a four-way system - yes ? The 208Esigma won't give much below 150Hz on OB .
I'm still aiming to have the Radian/Azura for the 800-8000 range in the fullness of time, myself .
"Once you find out ... the Circumstances ; then you can go out"
waveguide
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#1335

Post by waveguide »

IslandPink wrote:You could use that , yes, would be interesting . But that would be a four-way system - yes ? The 208Esigma won't give much below 150Hz on OB .
I'm still aiming to have the Radian/Azura for the 800-8000 range in the fullness of time, myself .
This intermediate system route is a safe way forward in my view. It may be so good that for some, it may be their main system in offering fine detail, at reasonable listening levels, whilst enough headroom for classical and folk or jazz. Great to have both.

This represents a more European aproach whilst the PA format, just gives that effortless power. The Marseilles or Fanfare for a Common Man.
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