High Displacement Postings


From: Erik Olson
Subject: 18"+ sealed driver comparison

I'm was looking at some drivers on Bill McFaddens page
http://www.rdrop.com/users/billmc/  and a couple drivers caught my eye.

I am considering building a couple of boxes with 6 or 12 NHT1259 subs  
total for the system.  Personally I like the -12dB/octave rolloff of
sealed boxes for that and other reasons.

The numbers for the Fane Colossus_24, Tekton, and Ultimate UWP1880DV
look very promising for a sealed box person like myself.
Does anyone know prices for these drivers and supply sources? 
I've only seen them on Bill's list and never in any catalogs.

Here are some numbers and calculations:

The numbers are for an unstuffed sealed box of Qtc=.707
Vas and Vb are cubic feet.  Dia and Xmax are meters.

Qts=0.48 Fs=15.00 Vas=36.40 SPL=101.0 Wrms=400 Dia=0.610 Xmax=0.019
Qtc=0.707  Fc=22.09 F3=22.10 Vb=31.12 Par=1.444 Per=18.17  Fane_Colossus_24

Qts=0.30 Fs=12.00 Vas=31.43 SPL=89.0 Wrms=300 Dia=0.457 Xmax=0.019
Qtc=0.707  Fc=28.28 F3=28.28 Vb=6.90 Par=1.253 Per=249.97  Tekton_KB_18

Qts=0.30 Fs=12.00 Vas=53.96 SPL=92.0 Wrms=400 Dia=0.533 Xmax=0.022
Qtc=0.707  Fc=28.09 F3=28.10 Vb=12.04 Par=3.029 Per=302.94  Tekton_KB_21

Qts=0.52 Fs=27.00 Vas=11.73 SPL=93.0 Wrms=250 Dia=0.457 Xmax=0.013
Qtc=0.707  Fc=36.71 F3=36.72 Vb=13.82 Par=1.719 Per=136.55 Ultimate_UWP1880DV

Qts=0.46 Fs=19.00 Vas=6.71 SPL=90.0 Wrms=150 Dia=0.305 Xmax=0.013
Qtc=0.707  Fc=29.20 F3=29.21 Vb=4.93 Par=0.132 Per=20.89  NHT1259

   
The Fane_Colossus_24 looks to be an impossible driver, like it breaks  
the laws of physics.  Too much SPL and too much low end bass, really big
box though.  Is this thing a real driver?

Now the Tekton_KB_21 looks like an incredible driver.  Now how much does
it cost?  Interestingly the two Tekton drivers below 20Hz have their
max thermal SPL equal to their max Xmax SPL in a .707 sealed box.
This means you can't damage the cone and surround by over excursion,
you can only melt the thing.  It must of been designed this way on purpose
since I've never seen any other drivers behave this way.

The Fane Colossus 24 has the equivilent displacement as 2.6 Velodyne
F1800R's.  The Tekton KB_21 has the equivilent displacement of almost
2 Velodyne F1800R's.  This is moving some serious air.

I can post plots on request on my webpage, but here is a summary:

Name       SPL Xmax limited 
-------    ---------------------------
Fane 24    112dB @ 20Hz   106dB @ 14Hz   <-- 2 of these can == a contra
Tekton 21  111dB @ 20Hz   105dB @ 14Hz
NHT1259    97dB  @ 20Hz   90dB  @ 14Hz   <-- 8 of these can == a contra

I admit these solutions are not as cost effective of a ContraBass but  
with a sealed box you have a -12dB/octave rollof, a simpler design,
less wear and tear / more robust.  Is it a better design, thats debatable,
I don't care I want to build one or two! 

erik olson

-----------------------------------------------------------------------

From: Erik Olson
Subject: 18"+ sealed driver comparison

> From: Noah Katz

> >  Dia=0.610   Fane_Colossus_24

> If the performance was based on this diameter, it's off some because the
> actual piston diameter is an inch or two less than the nominal frame
> diameter.
 
Already calculated that by saying    diameter *= 0.83;
Which says the effective piston diameter is about 20", not the original 24"

Now is the Fane Colossus 24 a real driver?
The specs make me think it isn't.
How much does it cost and who sells it?

How much do the Tekton 18 and 21" drivers cost and who sells them?

Anyone else have a favorite high displacement driver for a sealed box?

The NHT1259 is great but that is just too many drivers for the displacement
I want.  Twelve drivers is a lot and its a pain to cut that many holes!!

erik olson


-----------------------------------------------------------------------

From: "Jay B. Haider"
Subject: Re: 18"+ sealed driver comparison

At 04:05 PM 2/10/98 -0800, you wrote:

> Now is the Fane Colossus 24 a real driver?
> The specs make me think it isn't.
> How much does it cost and who sells it?
> How much do the Tekton 18 and 21" drivers cost and who sells them?

   Please forward any answers to these questions (that aren't from the BASS
list) to me.

> Anyone else have a favorite high displacement driver for a sealed box?
   
   You might want to try the JL Audio 15W6 or 18W6 for relatively small
enclosures but awesome output, especially if you're designing for HT.
Jay B. Haider

-----------------------------------------------------------------------

> From: Noah Katz
> Why not the ContraBass?

Ohhh man, I already answered that question in the original post.

I like the -12dB/octave roll off of a sealed box.  I believe that it
produces higher quality bass, below 20Hz, you can't hear it, who cares?  I do.
Two Fane Colosuss 24's can equal the 14Hz SPL of the ContraBass.
Since I'm talking sealed box, this means even more low bass below 14Hz
since the ContraBass is something like a 4th or 6th order passive radiator
system.

The sealed box is a lot simpler to build than a ContraBass with its
passive radiators, belts, motor, shafts, 2 drivers, ....

A driver in a sealed box is more robust, less moving parts, less things
to break / go out of alignment.  Since it's sealed the pressure of the
air will help things from ripping themselves apart like a vented design
below its port tuning F.

Granted any sealed box will have to be electronically assisted for the
same flatness a ContraBass has down to 14Hz, but I can and do accept that.
Actually I like EQing low bass inorder to tame those room modes.

Don't get me wrong.  I thought of building a ContraBass and I think that
web page is fantastic.  I love the ContraBass, I'm just too lazy and not
adventurous enough to try to build one!

erik olson

-----------------------------------------------------------------------

From: Noah Katz
Subject: Re: 18"+ sealed driver comparison

Erik Olson wrote:

> > Why not the ContraBass?
>
> Ohhh man, I already answered that question in the original post.

OK, all your reasons are good ones; in fact I went down that same path myself.
What I found  through software simulations was that at the low end, a vented/PR
system has a huge efficiency advantage (I forget exactly how much, but something
like 6 or 8 dB) over a sealed system, even after adjusting the drive shaft
diameter to give what should be good parameters (Fs=10 and Qts= .45). I really
don't understand why.

To achieve the levels in the low bass that the systems you describe are capable
of, you'll need kilowatts.

Noah Katz  Design Specialist   Solar and Astrophysics Labs

-----------------------------------------------------------------------

From: "Mark K. Long"
Subject: Re: 18"+ sealed driver comparison

Erik, the best driver I've found for sealed boxes is the Hartley.
They've got a very unique motor  with magnetic damping, which results
in a very low impedance peak.  They don't exactly obey T-S theory,
but in this case that's a good thing.

I'll be playing with the Contra for a while, so may part with some of
my extra drivers.  I've got one vintage 18" alnico red driver and
4 recent Alcomax III 24" drivers.  Xmax is around 0.75 inches.

Mark

-----------------------------------------------------------------------

> From: Noah Katz

> What I found  through software simulations was that at the low end
> a vented/PR system has a huge efficiency advantage (I forget exactly
> how much, but something like 6 or 8 dB) over a sealed system,

To me, the advantages of being sealed are worth the cost of 2X the drivers.


> To achieve the levels in the low bass that the systems you describe are
> capable of, you'll need kilowatts.

Not true.

In a Qtc = .707 sealed box my calculations show:

Fane Colossus_24  112dB @ 20Hz with 30W    105.7dB @ 14Hz with 21W
Tekton KB_21      111dB @ 20Hz with 381W   104.7dB @ 14Hz with 322W
NHT1259            97dB @ 20Hz with 25W     90.4dB @ 14Hz with 22W

These SPL values are Xmax limited.

The max SPL crossover points from Xmax limited to being Wrms limited is:
NHT1259           46Hz
Tekton KB_21      22Hz  actually Xmax limited == Wrms limited until 22Hz
Fane Colossus_24  47Hz

So it is Xmax that limits max SPL below the above frequencies and not Wrms.

erik olson

-----------------------------------------------------------------------

From: Noah Katz
Subject: Re: 18"+ sealed driver comparison

Erik Olson wrote:

> > To achieve the levels in the low bass that the systems you describe are
> > capable of, you'll need kilowatts.
>
> Not true.

I stand corrected; I should have said *I* need kW. My Vb will be 5 c.f., which
is what kills the efficiency. What's Vb for the Fane?

Noah Katz  Design Specialist   Solar and Astrophysics Labs

-----------------------------------------------------------------------

From: Erik Olson
Subject: Re: 18"+ sealed driver comparison

> From: Noah Katz
> > Not true.

> I stand corrected; I should have said *I* need kW. My Vb will be 5 c.f.,
> which is what kills the efficiency. What's Vb for the Fane?

Vb=5 for what?  Are you building a ContraBass?

Qtc=0.707  Fc=22.09 F3=22.10 Vb=31.12 Par=1.444 Per=18.17  Fane_Colossus_24
Qtc=0.707  Fc=28.09 F3=28.10 Vb=12.04 Par=3.029 Per=302.94  Tekton_KB_21
Qtc=0.707  Fc=29.20 F3=29.21 Vb=4.93 Par=0.132 Per=20.89  NHT1259_FA

The Vb's are in cubic feet and the sealed boxes are unstuffed.
It is said a stuffed 3.3 cu ft. box with the NHT1259 is Qtc = .707

So a stuffed Tekton_KB_21 would be about 9 cu ft. or less.
A stuffed Fane_Colossus_24 would still be > 20 cu ft, which is way to big.
So lets bump the Qtc up to .8 and we get:

Qtc=0.800  Fc=25.00 F3=22.43 Vb=20.47 Par=2.253 Per=28.37  Fane_Colossus_24

Now stuff it and you can fit it in a 2.3' x 2.3' x 2.3' box.
Still a big box but only 6 or so inches in each dimension bigger than a
Velodyne F1800R.  Not bad for 2.6 times the displacement of one!
Now the question is is the Fane_Colossus_24 a real driver and what does it
cost?

erik olson

-----------------------------------------------------------------------

From: Aaron Gilbert
Subject: Re: 18"+ sealed driver comparison

On Tue, 10 Feb 1998, Erik Olson wrote:

> Anyone else have a favorite high displacement driver for a sealed box?
>

        If and when I ever get around to making a subwoofer (building my
five satellites first, and I think they'll have some really good bass that
I can live with for quit some time), I will be using the Dayton
Loudspeaker Co. 15" Heavy Duty series II woofers.  They're available from
Parts Express (http://www.parts-express.com).  Pricing is $89 for 1-3, $80
for 4-11, and $72 for 12 and up!  :)  Now THAT would be some serious air
moving capability.  Their Xmax is great for a 15", 8 mm.  Rubber surround,
treated paper cone, 2.5" voice coil (300w RMS power handling), vented pole
piece, flat spider...basically the usual stuff.  I've done extensive
modeling of systems using these drivers, and for the price I think they're
hard to beat.  Plus they come with a five year warranty, which seems very
unusual for raw drivers, but no complaints from me!

        The only thing you might not like, is the high F3, which for a Qtc
of 0.707, is 39.5 hz.  However, it'll do that in a box of only 2.9 cubic
feet, which is tiny for a high excursion 15" I think.  I too prefer the
low rolloff of sealed boxes, and if you factor in room gain, that F3 will
actually give you very close to flat response (down maybe 5 dB) to 20 Hz.
The maximum output SPL is incredible, and even more so when you use two
per box, as I plan to do.  However, I plan to use a Qtc of 0.577 or so,
and then the response will only be down 10 dB at 20 Hz, which will just
about be made up completely by room gain.  The other cool thing about
using two wired in parallel, is the great efficiency, 95 dB.  Anways, here
are the specs so you can do your own calculations....I like 'em!

Model                   Dayton Loudspeaker 15" Heavy Duty series II
Parts Express #         295-130
Construction            treated paper cone, rubber surround, stamped
                        steel frame/basket
Power handling          300 watts RMS, 425 watts peak
Nominal Z               8 ohms
Re                      6.3 ohms
Magnet                  90 oz !
Net weight              15 lbs!
Fs                      19 Hz
Vas                     273 liters, 9.64 ft^3
Sd*                     .0855 m^2
Xmax                    .008 m
Qes                     .35
Qms                     10.46
Qts                     .34

* calculated, but from the dimensions it looks like this is pretty close.

Dimensions:     384 mm overall diameter
                352 mm cutout required
                171 mm deep
                156 mm magnet diameter


        Hope all this has been of some value to you!

Aaron

-----------------------------------------------------------------------

From: Noah Katz
Subject: Re: 18"+ sealed driver comparison

Erik Olson wrote:

> > I stand corrected; I should have said *I* need kW. My Vb will be 5 c.f.,
> > which is what kills the efficiency. What's Vb for the Fane?
>
> Vb=5 for what?  Are you building a ContraBass?

Sorry, yes, a CB.

> Now the question is is the Fane_Colossus_24 a real driver and what does it
> cost?

If it does exist, you can be sure it costs a lot more than it's worth on a
$/Vd basis. Have you checked outMcCauley's 18's?

Noah Katz  Design Specialist   Solar and Astrophysics Labs

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From: Edward Heath
Subject: Re: 18"+ sealed driver comparison

This never fails.  When someone expresses a preferrence for a sealed
box system, one of the reasons (usually the primary one) is that he
thinks it just sounds better.  The counter reply never deal with that
aspect of the assertion, only the ones that can be converted to numbers
(don't misinterpret me; I am NOT one of the technophobes).  Erik and I
agree on the point that the best SOUNDING bass comes from sealed boxes.

    I will supply the extra power, lug the extra weight, and foot the
bill for the quality of driver that it takes in order to get the sound
that I want.  Much of audio is compromise, and one is afforded the
luxury of deciding on which objective he wishes to hold ground with the
attendent necessity to give ground on others.  The taut well defined,
and controlled sound of acousticly suspended drivers are the ground that
many of us choose to claim, and to hell with the stuff we have to give
up to hold it.

     No measuerments, formulas or irefutable laws of physics can be
quoted loudly enough to make some of us abandon the one sonic fortress
we have decided is not expendable.

     Ed
     
    (Don't mean to speak for you Eric)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Erik Olson wrote:

> > From: Noah Katz
>
> > What I found  through software simulations was that at the low end
> > a vented/PR system has a huge efficiency advantage (I forget exactly
> > how much, but something like 6 or 8 dB) over a sealed system,
>
> To me, the advantages of being sealed are worth the cost of 2X the drivers.

-----------------------------------------------------------------------

From: HOBIE1DOG
Subject: Re: 18"+ sealed driver comparison

I talked to Kimon Bellas at Orca Design and he informed me that the 18 and 21"
drivers from Tekton were 1000.00 each, made in Italy, and were difficult to
sell here in USA, nobody will pay the price,so they discontinued them. 

-----------------------------------------------------------------------

From: "Heinz Mueller"
Subject: Re: 18"+ sealed driver comparison

On Tue, 10 Feb 1998 16:12:06 -0800, Noah Katz wrote:

> Why not the ContraBass?
I would answer, It's too slow, as also stated by a tone Engineer of the
Concert Hall in Stuttgart (Liederhalle) Germany.

Well we are in the "Fast Bass" regions again.
        
I personally would never consider building that device !
        
see ya on the bitstream
Heinz Mueller

-----------------------------------------------------------------------

From: awebb
Subject: Fane Colossus 24" (was:18"+ sealed driver...)

> Now the question is is the Fane_Colossus_24 a real driver and what does it
> cost?

Hi Eric,

I've used Fane drivers for several years in Pro-Audio / PA
applications. They are a well established british loudspeaker
manufacturer whose claim to fame was bringing high-power speakers
to those guitar heros back in the 60's (bringing the end of an era
to those Celestion Greenbacks or 'Pop 30's' as they were
unaffectionately known!)

Their 'Colossus' range are high power handling (600watts
continuous) pro-audio drivers, cast frames, heatsink fins on back of
magnet, 4" diam. V.Coil etc etc. Quality seems to be good, not up to
JBL standards, but perfectly good for the price. Recone kits easily
available, again I don't see this as a problem for Hi-fi use :-) 
Although after the last few days of 'Kilowatts a-go-go" talk I'm not
too sure...

Don't know if the 24" driver was ever a 'real product' (might phone
them tomorrow and see), however they do make a 15" and an 18" driver
which look promising.
        
While they're not true Sub drivers in the sense of the NHT1259, they
do compare say to the JBL 2226 (Fs in the range of 35-40 Hz)
        
The 15" unit looks especially interesting in a 6th order bandpass
enclosure. Maybe someone with the clever software could run these
numbers thru and make some suggestions?? :-)  Here's the numbers:

Fane Colossus 15XB

Fs = 37.6 Hz
Qes = 0.37
Qms = 2.19
Qts = 0.32
Vas = 144 litres = 5.1 cu ft
Ref Efficiency = 2.6%
Average Sensitivity = 99dB/1w/1m
Xmax = 0.56" pk-pk

Fane Colossus 18XB

Fs = 32.9 Hz
Qes = 0.46
Qms = 2.28
Qts = 0.38
Vas = 226 litres = 8.0 cu ft
Ref Efficiency = 2.9%
Average Sensitivity = 100dB/1w/1m
Xmax = 0.56" pk-pk


And prices here in the UK are (according to my latest price list)

15XB   119.55 Pounds = $US 186
18XB   134.98 Pounds = $US 209

The sensitivity is high enough to suggest experimenting with
mass-loading the cone somewhat to drop the Fs. Could be worth a try.

Hope this is useful, and if anyone feels like modelling some
possible enclosures, please let me know your results. TIA.

cheers,

Al Webb

-----------------------------------------------------------------------

From: Erik Olson
Subject: Re: Fane Colossus 24" (was:18"+ sealed driver...)

> Fane Colossus 18XB
...
> 18XB   134.98 Pounds = $US 209

Now that is a great price.

THe Fane Colossus 18XB in a Qtc=.707 sealed box which is 3.25 cu ft unstuffed
has an F3 of 61Hz, this just too much assitance to drop the F3 down
two octaves.  A sealed box isn't the right thing for this driver.

> Don't know if the 24" driver was ever a 'real product' (might phone 
> them tomorrow and see), however they do make a 15" and an 18" driver 
> which look promising.

Please let me know what you find about the 24" driver.

thanks,

Regarding the Re: 18"+ sealed driver... thread check out my web page
I created for this topic at:

[deleted]

It has sealed box calculations and plots for some high displacement drivers.

Maximum thermal and Xmax limited SPL are calculated for a varying frequency.
It's nothing fancy but it has all the numbers and the plots.

erik olson

-----------------------------------------------------------------------

From: Bill McFadden
Subject: Re: 18"+ sealed driver comparison

> I'm was looking at some drivers on Bill McFaddens page
> http://www.rdrop.com/users/billmc/  and a couple drivers caught my eye.
>
> The numbers for the Fane Colossus_24, Tekton, and Ultimate UWP1880DV
> look very promising for a sealed box person like myself.
> Does anyone know prices for these drivers and supply sources?   
> I've only seen them on Bill's list and never in any catalogs.

I got the Tekton driver data from this list.  I believe they're no longer
available in the US.  There's a little bit of info here:

http://uts.cc.utexas.edu/~speakers/archive/190.txt

I don't remember where I got the data for the Fane.  It may have also come
from this list.

Ultimate drivers were/are sold by Parts Express.  I bought a pair of
Ultimate 12" drivers a few years ago but had to return them because they
didn't measure anywhere near their published specs.  I found out later that
the manufacturer had changed the design to appease the car audio crowd but
hadn't bothered to update the spec sheet.

Bill McFadden  Tektronix, Inc.  P.O. Box 500  MS 50-350  Beaverton, OR  97077

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From: Noah Katz
Subject: Re: FANE Colossus

Dave Angus wrote:

> Hello:
>
> > From a FANE brochure (acquired Sept 1996), the largest driver is a
> > Colossus 18".

A 2 year old version of Boxmodel has the 24" listed in the driver database.

I believe the xmax was 9.5 mm.

I think it's preferable to get a given Vd from a smaller driver with a larger

xmax because, othe rthings being equal,  you'll get lower Fb and F3.

Noah Katz  Design Specialist   Solar and Astrophysics Labs

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From: "Rausch, Bernd"
Subject: Re: Fane Colossus 24" (was:18"+ sealed driver...)


http://www.tpu.fi/~mesaka/hifi/index.htm

The Author has built a sub with the 18XB. Maybe he has more infos
available

Bernd

-----------------------------------------------------------------------

From: Noah Katz

Heinz Mueller wrote:

> > Why not the ContraBass?
> I would answer, It's too slow, as also stated by a tone Engineer of the
> Concert Hall in Stuttgart (Liederhalle) Germany.

All opinions I've seen are exactly the opposite.

Noah Katz  Design Specialist   Solar and Astrophysics Labs

-----------------------------------------------------------------------

From: Nicholas McKinney
Subject: Re: Fane Colossus 24" (was:18"+ sealed driver...)

At 07:54 AM 2/12/98 -0000, you wrote:

> The Author has built a sub with the 18XB. Maybe he has more infos
> available

I work with these everyday and they do not impress me the least.  The main
complaint I have is that the suspension is very noisy.  Now that the
factory is supplying the recone kits partially assembled, you do get a
chance to see what real sloppy work is all about now too.

All in all there are much better drivers out there I beleive.  But the
Fanes are also pretty cheap here in the US too so maybe one could overlook
its faults.

Nicholas  

-----------------------------------------------------------------------

From: "Heinz Mueller"
Subject: Re: 18"+ sealed driver comparison

On Wed, 11 Feb 1998 23:34:43 -0800, Noah Katz wrote:

> Heinz Mueller wrote:
>
>> > Why not the ContraBass?
>> I would answer, It's too slow, as also stated by a tone Engineer of the
>> Concert Hall in Stuttgart (Liederhalle) Germany.
>
> All opinions I've seen are exactly the opposite.

I will go and hear them this weekend. But I'm sure, that I will find anything
as I don't like this mechanic aproach.

Maybe the problem is the same with this engineer, despite his longtime
experience and 
reputation.

-----------------------------------------------------------------------

From: WBamb83392
Subject: Re: 18"+ sealed driver comparison

In a message dated 98-02-12 02:53:37 EST, katz writes:

> Heinz Mueller wrote:
>  
>  > > Why not the ContraBass?
>  > I would answer, It's too slow, as also stated by a tone Engineer of the 
>  > Concert Hall in Stuttgart (Liederhalle) Germany.
>  
>  All opinions I've seen are exactly the opposite.

So which subwoofer drivers are universally considered "fast"?  So far, I've
heard that Dynaudio, Scan-Speak 85XX, JBL 2226, horns, and dipoles are
universally "fast".  Horns and dipoles have in common an extremely low Q, but
the Dynaudio in particular puzzles me.  

  Anyway, an array of cheaper drivers is better than one monster 86" driver.
Cone breakup problems, power delivery requirements, and box flatness are
reduced.  The displacement per dollar is also higher for smaller, higher
production woofers.  Also, when you tire of having a 25ft^3 sub, you can
separate it into subs for all your friends!

-Eric Bamberg

-----------------------------------------------------------------------

From: Aaron Gilbert
Subject: Re: 18"+ sealed driver comparison

On Thu, 12 Feb 1998 WBamb83392 wrote:

> So which subwoofer drivers are universally considered "fast"?  So far, I've
> heard that Dynaudio, Scan-Speak 85XX, JBL 2226, horns, and dipoles are
> universally "fast".  Horns and dipoles have in common an extremely low Q, but
> the Dynaudio in particular puzzles me.  

        I thought the correct answer (based on current posts by people who
know what they're talking about, I'm very marginal in that regard) was
'none'.  If by fast you are talking about acceleration, keep in mind that
a larger driver moves proportionally less distance for a given SPL at a
given frequency than a smaller driver.  (though I suppose you are
comparing a large driver with an array of smaller drivers with equivalent
area, so nevermind what I just said).  

>   Anyway, an array of cheaper drivers is better than one monster 86" driver.
> Cone breakup problems, power delivery requirements, and box flatness are
> reduced.  The displacement per dollar is also higher for smaller, higher
> production woofers.  Also, when you tire of having a 25ft^3 sub, you can
> separate it into subs for all your friends!

        Exagerrations aside (I'd like to see that 86" driver!), since when
did cone breakup become an issue with subwoofers?  Certainly for
midwoofers which extend all the way up to 2kHz or higher, I can
understand, but a subwoofer crossed over at 100 Hz fourth order?  Doesn't
make sense to me.  Also keep in mind that a larger driver will be more
efficient than a small one, in many cases significantly so.  I'm not sure
what sizes of woofers your are comparing here for your single sub vs your
array (I'd hope it's something more realistic than say 86" vs 4", for
example 15" or 18" vs 6-10 6.5" drivers).  It's quite common for a good
15" to have 10 dB more efficiency than a 6.5" driver, I'm not going to do
the math tonight, so maybe you could overcome that problem with a clever
scheme of parallel series wiring and still end up with a normal impedance.
Seems like a hassle to me though.  And as far as the price, that also
doesn't make sense.   About the cheapest woofer (SCH and MCM excluded for
this comparison) I've found is around $20-$25, that would be for a 5.25".
I can get a long excursion (8mm) 15" for only $90, and it will have
drastically more Vd and be better in just about every respect than any
combination of smaller drivers, excepting box size.  You only get a couple
good 6.5" drivers for that price (or 2/3 of a SS or DYN), not the NINE you
would need to get the same Vd.  Seems like a no brainer.  

        If you're thinking more along the lines of 8", 10", or 12" vs the
larger sizes, ok, no problem, but all those drivers start getting really
expensive too, just look at the DV12 and 1259.  Excellent drivers, but
value leaders they are not, they're what you use when you want the best
regardless of the cost.  (IMHO including Dynaudio)  

Anyways...sorry to ramble on.  There are some pretty good values out there
on major woofage, but I don't think they come from the manufacturers we're
all used to hearing on this list....

Aaron

-----------------------------------------------------------------------

From: "Mark K. Long"
Subject: Re: 18"+ sealed driver comparison


My personal favorite is the Hartley 18 and 24" drivers.  There was an
article in speaker builder in '89 with the 24" in a dipole, a friend
had the 24 in a sealed box.  My favorite was the 18 in a folded corner
horn....just incredible.  They have a somewhat unique motor design
with magnetic damping.  I don't remember the number, but the impedance
peak at responance is very low. <20ohms?

Mark

-----------------------------------------------------------------------

From: WBamb83392
Subject: Re: 18"+ sealed driver comparison

In a message dated 98-02-12 05:46:36 EST, teslor writes:

     I thought the correct answer (based on current posts by people who
 know what they're talking about, I'm very marginal in that regard) was
 'none'.  If by fast you are talking about acceleration, keep in mind that
 a larger driver moves proportionally less distance for a given SPL at a
 given frequency than a smaller driver.  (though I suppose you are
 comparing a large driver with an array of smaller drivers with equivalent
 area, so nevermind what I just said).  
 
  "Fast bass" as nothing to do with acceleration, but I would like to know
which drivers are considered "fast sounding" so that I can quantify the
subjective "speed".  The "fastest" sub I have is a sealed box with a Q of .3
and a very stiff, light aluminum cone.  It is equalized by a big inductor.
Nobody else uses a design like that (probably because it's expensive and not
loud), yet they claim "fast bass".  So I want to know what my sub and
criteria have in common with others criteria and subs.

     Exagerrations aside (I'd like to see that 86" driver!), since when
 did cone breakup become an issue with subwoofers?  Certainly for
 midwoofers which extend all the way up to 2kHz or higher, I can
 understand, but a subwoofer crossed over at 100 Hz fourth order?  Doesn't
 make sense to me.

Maybe I used the wrong word.  A 30" diameter cone driven at its center is
going to flex and distort a lot more than the eqivalent composed of 6 12"
cones with 6 driven points.

 Also keep in mind that a larger driver will be more
 efficient than a small one, in many cases significantly so.  I'm not sure
 what sizes of woofers your are comparing here for your single sub vs your
 array (I'd hope it's something more realistic than say 86" vs 4", for
 example 15" or 18" vs 6-10 6.5" drivers).  It's quite common for a good
 15" to have 10 dB more efficiency than a 6.5" driver, I'm not going to do
 the math tonight, so maybe you could overcome that problem with a clever
 scheme of parallel series wiring and still end up with a normal impedance.
 Seems like a hassle to me though.

For a given F3, Q, cone area, and sealed box size, all drivers are very
closely the same efficiency.  An array of 6.5" drivers with equal cone area
to an 18" in an identical sealed box will have the same efficiency in the
bass range.

 And as far as the price, that also
 doesn't make sense.   About the cheapest woofer (SCH and MCM excluded for
 this comparison) I've found is around $20-$25, that would be for a 5.25".
 I can get a long excursion (8mm) 15" for only $90, and it will have
 drastically more Vd and be better in just about every respect than any
 combination of smaller drivers, excepting box size.  You only get a couple
 good 6.5" drivers for that price (or 2/3 of a SS or DYN), not the NINE you
 would need to get the same Vd.  Seems like a no brainer. 
 
That Dayton 15" does seem like a good deal, doesn't it.  I think an array of
10"-18" drivers are better than one expensive 18"-30", not an array of 6.5".
Don't disregard SCH, though.  I just visited them in Eugene the other day,
and
was very, very impressed.  Most of their drivers are made by KSC, with a few
by Tonegen.  The 18" they sell is an exceptional bargain, even if it did used
to be the Radio Shack 18".  I'll probably tell all about SCH in a seperat
post.

 
 Anyways...sorry to ramble on.  There are some pretty good values out there
 on major woofage, but I don't think they come from the manufacturers we're
 all used to hearing on this list....

Which manufacturers?  KSC, Lyeco, BC, etc. ?  Just try and get your hands on
some without buying 5000 units or paying 100% dealer markup (SCH excluded).
From my spreadsheet, the best deals for displacement and motor strenght per
dollar were  (in order) the SCH 18021, Dayton 15", Contrabass, Swan 305, and
Eclipse 1238.  I would pit an array of any of those against any 18"+ any day.

 
 -Eric Bamberg

-----------------------------------------------------------------------

From: Erik Olson
Subject: Re: FANE Colossus

> From: Noah Katz
> A 2 year old version of Boxmodel has the 24" listed in the driver database.
> I believe the xmax was 9.5 mm.

Bill McFaddens page says the Xmax for the Fane Colossus 24" is 0.740" which
is close to 20mm, hmmm, this looks suspiciously like twice the 9.5mm number.


> From: "Mark K. Long"
> My personal favorite is the Hartley 18 and 24" drivers.  There was an
> article in speaker builder in '89 with the 24" in a dipole, a friend
> had the 24 in a sealed box.  My favorite was the 18 in a folded corner
> horn....just incredible.  They have a somewhat unique motor design
> with magnetic damping.  I don't remember the number, but the impedance
> peak at responance is very low. <20ohms?

Hartley?  Could you post some TS parameters, cost, vendor, web page, ....,
something so that I can find out more about this driver?


> From: Aaron Gilbert
> Anyways...sorry to ramble on.  There are some pretty good values out there
> on major woofage, but I don't think they come from the manufacturers we're
> all used to hearing on this list....

You mean car driver companies?  The drivers from most are designed usually
for the smaller box and car lowend cabin gain.  F3's are a little high,
and the Xmax's are typically about .5", since a flat lowend is mainly
about displacement and not wattage, gobbs of lowend EQ boost could make
these drivers work quite well in a sealed box in the home.  What I really
am looking for is an 18" or so driver with an Xmax of .75"+


Check out my quest for the high displacement driver in a sealed box at:

[deleted]

erik olson

-----------------------------------------------------------------------

From: Thomas VanHorn
Subject: Re: FANE Colossus

At 12:25 PM -0800 2/12/98, Erik Olson wrote:
> Hartley?  Could you post some TS parameters, cost, vendor, web page, ....,
> something so that I can find out more about this driver?

The 24 " Hartly driver is sold from the factory in a large infinite baffel
alignment.  I don't have any data on the raw driver but they may sell it
direct.

The only DIY project I have seen and autitioned was the Mark Levensin HQD
(Hartly-QUAD-Decca ribbon) The woofer boxes were infinite baffel enclosures
of 18 cu. ft.  This was in 1975.  A freind demo'd his home made pipe organ
tapes
made on a NAGRA.  It was pretty awesome for 1975.  I think the NHT 3.3
would sound pretty good with those same tapes but then I'm biased. And old
enough to protect what little hearing I have left. The address for Hartley
is in the back of Audio Mag Ann Eq issue which I can't find at the moment.

-----------------------------------------------------------------------

From: "Brian Steele"
Subject: Re: 18"+ sealed driver comparison

At 10:56 PM 10-02-98 CST, you wrote:
> This never fails.  When someone expresses a preferrence for a sealed
> box system, one of the reasons (usually the primary one) is that he
> thinks it just sounds better.  The counter reply never deal with that
> aspect of the assertion, only the ones that can be converted to numbers
> (don't misinterpret me; I am NOT one of the technophobes).  Erik and I
> agree on the point that the best SOUNDING bass comes from sealed boxes.

This may be true in many cases, but I think that this is more of a room
effect than the actual alignment.  What happens if the port of a vented
system is tuned at or near one of the room modes?  Also, consider that the
room modes get worse as the frequency lowers.  You might end up with a
better sounding bass system if it actually DOESN'T extend low enough to
excite the lower modes.

Case in point with my new center channel speaker, which I "finished"
yesterday (will send another message to the list on this soon).  It's a
ported system, and the bass does sound quite boomy in one of my measuring
spots, but that's because the system extends down to 50 Hz and room modes
at approx 66 and 44 Hz (BAD problems here) are being excited.  When I
sealed the port, it sounded much better, but only because the 44 Hz mode
was no longer being excited (F3 of sealed system > 90 Hz).  I moved the
speaker to another location where the room effects weren't so bad, and it
sounded pretty good when it was left ported.

The bottom line is that your room is going to have a lot to say about the
final results you get in the bass region.

Regards,
Brian

-----------------------------------------------------------------------

From: "Mark K. Long"
Subject: Re: FANE Colossus


Erik Olson wrote:
> Hartley?  Could you post some TS parameters, cost, vendor, web page, ....,
> something so that I can find out more about this driver?

Hartley Products Corp 
5732 Oleander Dr, Wilmington, NC 28403-4714
Phone: (910)392-0500 Fax: (910)392-1077 

These drivers are handmade in North Carolina, Last time I check they
were going for $700 for the 18" and $750 for a 24". Although they do
show up occasionally on the used market for cheaper.  

haven't seen any info on the web.  Don't know if you are familiar with 
the "HQD" system built by mark levinson in the 70's, used the hartley
24, quad for midrange, and decca tweeter.  

as for TS parameters, the corporate line is that TS analysis doesn't
apply because the drivers are *magnetically* damped.  TS assumes
linear damping. and most of the measurements are done using "small
signal" analysis, which may not apply at real "in room" levels.
Excursion is 0.75 in.  I might have some other info at home in some
old paperwork.  The motors are alnico, "Alcomax III" I believe.

Mark

-----------------------------------------------------------------------

From: Douglas Purl
Subject: Re: FANE Colossus

On Wed, 11 Feb 1998, Noah Katz wrote:

> I think it's preferable to get a given Vd from a smaller driver with a larger
> xmax because, other things being equal, you'll get lower Fb and F3.

This was precisely the rap on the Hartley 24" driver.  Even in large
boxes, its already unspectacular Fs was driven high by the box volume, and
it made a poor deep-bass reproducer.  I have written here before of the
results when we put AR3-As side by side with absolutely gorgeous cherry
wood Electro-Voice Patricians with 30" woofers.  The ARs seemed to go an
octave deeper.  There was a sibilance in the Patricians that enchanted
their owner, but a decided bass weakness on comparison.  Bass loading is a
very staightforward matter of physics, notwithstanding the cajolings of
the audio journalists.

Doug Purl

-----------------------------------------------------------------------

From: Aaron Gilbert
Subject: Re: 18"+ sealed driver comparison

On Thu, 12 Feb 1998 WBamb83392 wrote:

> That Dayton 15" does seem like a good deal, doesn't it.  I think an array of
> 10"-18" drivers are better than one expensive 18"-30", not an array of 6.5".
> Don't disregard SCH, though.  I just visited them in Eugene the other day, and
> was very, very impressed.  Most of their drivers are made by KSC, with a few
> by Tonegen.  The 18" they sell is an exceptional bargain, even if it did used
> to be the Radio Shack 18".  I'll probably tell all about SCH in a seperat
> post.

    Haven't disregarded them yet, I continue to check back there every
once in a while to see what comes up.  :)  The Dayton indeed seems like a
great deal though, as far as I can tell it's only shortcoming is the
rather high F3, which isn't THAT high at 40 Hz, still as good as the
AC12E/W1238R.  I think SCH is probably a better place to buy Radio Shack
drivers than Radio Shack itself.  Or maybe I'm just going to the wrong
Radio Shacks.  Last time I went there to buy some drivers, the guy barely
spoke any English, much less knew what a driver was.  I asked to see the
woofer drivers that were on sale, and he kept asking me how many watts.
Huh?  You do have drivers here, don't you, they're on sale now??
Sometimes it feels like a 7-11...

> Which manufacturers?  KSC, Lyeco, BC, etc. ?  Just try and get your hands on
> some without buying 5000 units or paying 100% dealer markup (SCH excluded).
> From my spreadsheet, the best deals for displacement and motor strenght per
> dollar were  (in order) the SCH 18021, Dayton 15", Contrabass, Swan 305, and
> Eclipse 1238.  I would pit an array of any of those against any 18"+ any day. 

        Well, you got some of the ones I had in mind.  Dayton, Eclipse,
Swan....my original reference was merely a [perhaps incorrect] observation
that the 1259 and DV12 seem to enjoy vastly more popularity among the
DIYer crowd.  I do forget though that this list has so many members, easy
to do with so few people actually posting.  Not that those aren't great
drivers, but I wouldn't call them value leaders...unless of course you
just must have a 12" that goes down to X at the -3 dB point in a box of X
cubic feet, they may be the only game in town..

Aaron

-----------------------------------------------------------------------

From: "Ron Erickson"
Subject: Re: FANE Colossus

> Date:          Thu, 12 Feb 1998 15:54:05 -0700 (MST)
> Reply-to:
> From:          Douglas Purl
> Subject:       Re: FANE Colossus

> On Wed, 11 Feb 1998, Noah Katz wrote:
> 
> > I think it's preferable to get a given Vd from a smaller driver with a
> > larger xmax because, other things being equal, you'll get lower Fb and F3.
> 
> This was precisely the rap on the Hartley 24" driver.  Even in large
> boxes, its already unspectacular Fs was driven high by the box volume, and
> it made a poor deep-bass reproducer.  

My friends who use them, use the basement as the box.  They go low 
that way.  One of my friends used a pair of 24's on each side with 4 
15" JBL's above.  He had floor jacks in the basement in an attempt to 
keep the floor from moving too much.  He went to multiple 18's 
because he kept breaking the Hartley's (he has enough power to 
break just about anything).  He likes organ music and 8 hz was his 
goal.

Ron Erickson

-----------------------------------------------------------------------

From: Noah Katz
Subject: Re: 18"+ sealed driver comparison

> >> > Why not the ContraBass?
> >> I would answer, It's too slow, as also stated by a tone Engineer of the
> >> Concert  Hall in Stuttgart (Liederhalle) Germany.
> >
> > All opinions I've seen are exactly the opposite.
>
> I will go and hear them this weekend. But I'm sure, that I will find
> anything as I don't like this mechanic aproach.

Also don't forget that a  great sub can be rendered "slow" and  boomy by the
room and/orplacement in it.

> Maybe the problem is the same with this engineer, despite his longtime
> experience and  reputation.

I don't understand.

Noah Katz  Design Specialist   Solar and Astrophysics Labs

-----------------------------------------------------------------------

From: Nicholas McKinney
Subject: Re: FANE Colossus

> as for TS parameters, the corporate line is that TS analysis doesn't
> apply because the drivers are *magnetically* damped.  TS assumes
> linear damping. and most of the measurements are done using "small
> signal" analysis, which may not apply at real "in room" levels.


I think that what they might mean by magnetically damped is a pair of high
conductivity rings placed at either end of the VC former.  When these rings
go into the magnetic gap, they act as magnetic brakes and thus prevent the
driver from moving any further.  This I beleive would have as much bearing
on the TS parameters as a drastically progressive suspension would have on
the CMS.  At the small signal levels used for TS, you just won't see what
is going on in either of these cases. 

The only drivers I know of personally (I have not been inside a Hartley)
with this setup is the Rockford Fosgate pro series.  The rings are seperate
coil windings without any coating, thus making one large shorted ring.
They are only shorted to themselves, and are about 1/4" tall and spaced
whatever the xmax distance from the coil winding you wanted if memory
serves me well.  Thus you need a really deep motor system to keep the VC
from bottoming.

My opinion is that they are a good way to thermally blow up a driver.  Once
the driver is pushed to the ring set limit, dumping more power changes the
sound little as the cone moves the same distance.  I did not care for them
at all.

Who knows, this might not even be what the Hartley is using and I am just
rambling :~)

Nicholas 

-----------------------------------------------------------------------

From: Thomas Danley
Subject: Re: 18"+ sealed driver comparison

> From: Noah Katz
> To: Heinz Mueller
> 
> > >> > Why not the ContraBass?
> > >> I would answer, It's too slow, as also stated by a tone Engineer of
> > >> the Concert Hall in Stuttgart (Liederhalle) Germany.
> > >
> > > All opinions I've seen are exactly the opposite.

Yep, I have never heard of any reviews where they wern't impressed with
the precise bass.

> >
> > I will go and hear them this weekend. But I'm sure, that I will find
> > anything as I don't like this mechanic aproach.

I can see where Philosophically  the aproach may not be your cup of tea,
but you might consider going into an audition with an open mind.
What is it about the aproach that you don't like?

> Also don't forget that a  great sub can be rendered "slow" and  boomy by
> the room and/orplacement in it.

Very true, a large hall can make nearly anything sound slow / boomy.
The best situation is to hear one outside where there are NO room
effects or even in a normal living room

> > Maybe the problem is the same with this engineer, despite his longtime
> > experience and reputation.

As a professional sound engineer (I assume a "tone engineer" is) it is
VERY unlikely that he has ever heard ANY speakers that cover the 16 - 30
HZ octave, or are low in harmonic distortion, or he may be predisposed
to think that that a "mechanical" speaker simply "Can't" respond fast
enough to reproduce music etc. 

Tom

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