[randog]

It's been a long time since this thread was first posted and I should have gone back to the beginning before making my post. It would have answered some of my questions.  

[David Ellis]

There is also a valid point that I haven't addressed yet.

The 3 way with the 10" on the bottom might just work with many/all of the parts from the 1801b.  I certainly cannot promise this, but it seems like a reasonable hope.  I have a hunch the lower sensitivity of the 10" SEAS drivers will accomodate the W18E001 driver with the smaller magnet.

I have a couple of the W26 drivers.  They look very nice and I am very pleased to see that SEAS didn't put any insulation between the voice coil and former!  The Former is raw/uncovered anodized aluminum.  It should make a glorious heat sink.  The downside to the W26 drivers is the cost - $ ouch.  They are expensive.  I don't have the L26's yet so I haven't started any testing.

 Also, my eyes remain slightly fuzzy following my PRK surgery and I still have about 7pair of 1801s needing rubbing + assembly for current customers.  These current speakers are obviously a higher priority.

Dave

[Al Garay]

With fuzzy eyes, you are better off working on crossover.  

That's a great idea on the W26 or L26 3-way to provide an upgrade path for the 1801s.

The specs on the W26 ($238.50) are almost identical to the L26 ($108). Could they be a drop in replacement?

Al

[David Ellis]

The specs on the W26 ($238.50) are almost identical to the L26 ($108). Could they be a drop in replacement?

My comments on this are somewhat informed, but have NO directly tested support.

First, the W26 does indeed have shorting rings.  This has two effects with regard to implementation.  The first is less sensitivity.  The sopper rings effectively constrict the flux between the top plate and pole piece.  The result is less sensitivity and a slightly higher Qes.  With some neodymium augmentation magnets placed on top of the top plate, this problem could be mitigated.

Second, while the W26 doensn't indicate less inductance in the factory specs, I suspect the W26 actually has less inductance.  This inductance must be integrated into the crossover design IF (and only if) a sufficiently high crossover frequency is present.  At a low crossover frequency the inductance won't be a factor.

All of this presumes the shape of the driver's response curves are the same.

Soooo, it might be possible to swap the drivers.  

Dave

[totti1965]

Hallo David,

Perhaps you are interested:

There is a third alternative for the woofer of your large speaker!
But I don´t know if it is aviable in the United States.

I know, the Excel W 26 FX 001 is one of the best Bass Drivers in the world.
It is perfect for fitting in a sealed cabinet:

The mesured Datas of Mr. Timmermanns from our german "speaker builder" Magazin of several chassis are (don´t trust the Excel guys!)

Diameter: 269 mm
V as 217 liters
Q ts     0,30
Fs      18 Hz
X max    6 mm
the losses are R ms 3,3 kg / s

the perfect fit in a sealed cabinet with 10% resistance losses (Q ts   0,33 realistic) and
Q tc (build in)  0,57735
is

86,17 liters   in a sealed cabinet (not so good for vented cabinets- needs exact 140 liters! but then moves down to    f 3   16 Hz!!!!!)

Computer Simulations shows that it needs 140 liters if you want to build it in in a vented cabinet. Than you need a Bassreflex tunnel Diameter of 100 mm (4 inches) and the tunnel has to become 450 mm long (18 inches)





The alternative in my oppinion is the following:

The world record holder in some kind of datas
is the new Visaton TIW 200 XS

Diameter:    222 mm
V as 76 liters
Q ts  0,40
Fs     27 Hz
X max 11 mm (world record holder!)
the losses are R ms 0,60 kg / s (world record for 8  1/2 inch woofers!!!)

the perfect fit in a sealed cabinet with 10% resistance losses (Q ts   0,44 realistic) and
Q tc (build in)  0,57735
is

77,63 liters in a sealed cabinet

it has the best ventilation- measures ever seen in a woofer

the performence in a vented cabinet  is great:
85 liters vented cabinet brings an f 3 point of 21 Hz!!!!!!

The reflex tunnel has to become 70 mm in diameter and exact 200 mm (8 inches long)

The Visaton TIW 200 XS is build in Germany. The maximum SPL is extrem, because it is the world record holder in X max!
It is the definite 10 inch woofer killer because of it can move more air than nearly any 10 inch woofer!

The coil carrier is made of capton.  The woofer doesn´t use a paper or metal cone. The cone is made of a flass fibre -polyester sandwich Combination. Hope you are not so dogmatic in cone materials.........

the maximum SPL of a 10 inch woofer in a sealed cabinet that has X max  + -  5 mm ( the Excel W 26 FX 001 can slightly more):

 20 Hz      88,0 dB
 30 Hz      95,0 dB
 40 Hz     100,0 dB
 50 Hz     103,9 dB
 60 Hz     107,0 dB
 70 Hz     109,7 dB
 80 Hz     112,1 dB
 90 Hz     114,1 dB
100 Hz    115,9 dB




the maximum SPL of one Visaton TIW 200 XS in a sealed cabinet  X max + - 11 mm
 
 20 Hz      90,2 dB
 30 Hz      97,3  dB
 40 Hz     102,3 dB
 50 Hz     106,2 dB
 60 Hz     109,3 dB
 70 Hz     112,0 dB
 80 Hz     114,4 dB
 90 Hz     116,4 dB
100 Hz    118,2 dB


You can see, the maximum sound pressure is quite equal or slightly better than this of conventionel 10 inch speakers.
(Even if you don´t use 100 % of the possibilities you have, because of some dynamically effects that makes problems if you want to use it for techno-partys 24 hours a day  )


The MLSSA  of the Visaton TIW 200 XS is beautyfull up to 1500 Hz, so you can use it up to 1000 Hz.
Frequency responce is perfect up to 1000 Hz (absolutely flat!)
Sensitivity:  same curves as the Excel W 26 FX 001 (about 85 to 86 dB) and in the computer simulation about 81 to 82 dB build in.
The response answer in internal Baffle is beautyfull.

Mr. Timmermanms from "hobby hifi"  our german speaker builder magazin who has tested more than 1000 speakers in his live was so impressed, that he wrote:
The Visaton  TIW 200 XS opens a new Dimension of Woofer Construktion. One of the best Woofers ever at any price!
The price that it costs is amazing and has nearly the Qualities of a sensation!



In Germany the price of an Excel W 26 FX 001     is  EUR    371,-   (each)

the price of the Visaton TIW 200 XS is                      EUR 125,-   (each)



ever the best wishes,


yours



Thorsten

[David Ellis]

Your comments apply directly to the string titled 10" on the bottom .  I suggest some reading therein.

Somehow the 10" discussion got dragged into this forum.  I should have caught this sooner.

I do expect the L26 or W26 to perform well.  I do not expect either will equal the SCC300.

Dave

[wwmeatman]

I really like my 1801's.  After reading this topic especially the comments posted by Dave on further improvement in midrange clarity crossing the W18 at 250htz I decided to try and add some bass modules.  I did a lot of looking at watt puppies and JA pearls and after some math decided I'd like to try the dual 8" route.  I measured the pearls base cabinet size.  I checked the F3 on some Seas L22 AL woofers in a similar vented cabinet  of roughly 2 cu ft.  They came in at an F3 of 23HZ.   I also did some math on making the W18 work in a sealed cabinet crossed at 250HZ.  For all the reasons Dave outlined on cutting complex angles I just built each box and glued them together.  Like the 1801's the new cabinets are very well braced.   They are stuffed with acoustistuff.  I kind of used the vandersteen approach to minimizing the cabinet to minimize edge diffraction.  I used the 1801b drivers and crossover exactly as is.  I took the easy way out on the bass crossover and used a marchand XM9 and a separate amp so I could avoid all of the phase, timing and balancing problems.  This also helped with the impedance problems that would come from trying to drive 2 more speakers on each channel.      

The end result is beyond what I had hoped for.  The bass response is tight and well defined.  Dave was also right about getting the base correctly located to achieve the best imaging and sound staging.  I think the bass from the L22’s is as good as the midrange and high response of the 1801's.  Bass guitars, bass drums, bass saxophones, all sound like they are in the room.  The midrange of W18’s opened up and sounds even better now.  Van Morrison, Diane Krall and Sting sound even more lifelike if that is possible. I am very impressed with both the amount of depth and the openness/airiness of these speakers.  

I think they sound as good as or better than any speakers I have ever heard.

Thanks Dave for making a great kit and for your ideas.  You have made me a very happy guy.  
 

Here are a couple pictures.  
http://members.cox.net/thayes12/Speakers1
http://members.cox.net/thayes12/speaker2

[Ravi]

Great work Meatman!

BTW, what is the MDF wall thickness that you used for the L22 bass modules? Did you use any internal braces in the bass module?  Is it fairly inert?

Thanks.

[wwmeatman]

FWIW -- The base modules are built out of .75 MDF with internal braces running front to back.  They divide the cabiet into three unequal parts.  I used a big hole in the front of the brace and a lot of small holes in the back.  That way the back area of the braces help hold the extra stuffing in place.  The cabinets sound the same as an 1801 cabinet when you rap on the side.   I put the rear port at the bottom of the cabinet.

I built these to test and I am sure there are probably many ways to make them better.   Trouble is they sound so good I am not motivated to build another set right now.

[David Ellis]

This appears to be a most excellent implemenation of DIY at it's best.  I too believe you created a truly excellent speaker.  Once upon a time, such sound quality seemed way out of reach for guys like me.  I am sure you felt the same.  Now, you built it, and it's in your living room.  I suspect you will never purchase another commercial speaker again.

I thought about dual 22cm drivers too, but decided that a single 26cm SEAS cone would do equally well at less $.  This obviously remains to be seen/heard.  Nonetheless, a pair of 22cm drivers should perform extremely well.

Congradulations on the success of your project.

I do have a question about your feelings on your DIY project.  Do you feel:

1.  Historically cheated because commercial loudspeaker companies abused your cashflow for so many years?

2.  Extremely pleased following sonic decimation of commercial products at $5x or more?

For me, it's number 2.  Initial conquest made me grin from ear to ear!  While continued conquest makes me feel good, I experience most of this from customer feedback.  I also find it very pleasing when a customer/friend finds success following information exchange!  Your success makes me very happy.

Thanks for experimenting and posting!

Dave

[wwmeatman]

Dave

I feel the same.  Speaker companies should go ahead and charge whatever the market will bear.    

It wasn’t so long ago I was in the super high end audio store in a major city (nameless) lusting over some JA Pearls and wondering  if I could ever bring myself to spend that kind of money.  Thanks to you there is no more dilemma.

BTW -- We are racing June 4th and 5th at Glenwood. Be sure and bring the boys over if you have time.  I am number 76.  Just tell them you are with me and they’ll let you in without a charge.  

Thanks again

Tom

[David Ellis]

Speaker companies should go ahead and charge whatever the market will bear.

Yeah, I agree.  I also agree the JA Pearl is a wonderful sounding speaker.  I don't know how many more Wilson Watts will are sold following the introduction of the JA Pearl, but there should be very few IMO.  I thought the JA Pearl was a much better sounding speaker for the same commercial $.

I'll most likely come on the day with better weather in June.  If the weather looks the same, I'll come on the day more favorable to family events.  I checked the motorplex calendar and the 5th,6th indicated "8:00AM  GPR PCA DE and Race ".  Is this correct?

Dave

[wwmeatman]

Yes that is the correct event.

Here  is the link to the Great Plains Region Website

http://vista.pca.org/gpl/race_info2.html

The schedule should be there one of these days.

Look forward to seeing you if you have time

Tom

[tg3]

Because almost NO drivers are perfect, an electronic crossover will never equal the sound quality of a well implemented passive crossover. This is simply because the passive crossover will be flatter.

This comment should be qualified.

The comment is TRUE if the active XO has only fixed slopes, ie, 4th order LR.

The comment is FALSE if the active XO is designed in conjunction with the measured drivers response to deliver a target acoustic response. Any passive XO can be emulated with an active design, given the proper XO CAD software.

Best regards.

[stvnharr]

wwmeatman/Tom,
I don't frequent this forum too often anymore, sorry Dave, but I happened on this this evening and I really like your speakers.  
I built a pair of 1801's nearly 2 years ago, and almost immediately wanted to build some kind of bass module, 3-way, or something to fill in the low end.  Dave and I had numerous emails on the subject at the time.
I liked the idea of a dual 8" bass module w/L21's.   Your idea of using a Marchand and another amp is fabulous, as long as the money isn't a concern.  I think that's really the best way to go.
I ended up going to a 2.5 way w/a second W18.   It's the best speaker nobody but me has heard!!!!!!!!!  But it doesn't do the low bass like your bass module does!!!!!
You will never want for another audio speaker, EVER.
Congrats!!!!!


BTW, the concern about one large bass driver or 2 smaller bass drivers is something I remember reading about several years ago as per B&W 801 or 802.   The single large driver does have a small edge, of which I am too deaf to really hear.   But I think the biggest difference is in cabinet size to accomodate the larger driver vs. dual smaller drivers, IMO anyway.

[David Ellis]

Thanks for your comments Steve.  I feel prompted to address some things.

The connection between driver(s) and cabinet is fairly simple after some dissolving.  After dissoliving all the T/S numbers, the basics are true.

1.  Bass depth is directly proportional to cabinet size.  Deeper bass requires a bigger cabinet.

2.  Sensitivity per watt is directly proportional to cabinet size.  More sensitivity requires a bigger cabinet.

The above are true regardless of how many woofers are used.

So, there is no real difference with regard to trading cabinet size for multiple woofers.  If the double (smaller) woofer produce the same sensitivity/watt and the same bass depth, then they require the same cabinet size as the single bigger woofer.

There are some commercial marketing assault herein.  The most prominent issue is that speakers are generally conveyed with a sensitivity db/2.83 volt rating.  The result is that speakers with a lower impedance (i.e. 2 woofers) APPEAR to provide twice asmuch output per unit of energy used.  This is not true    , when watts are considered.  A speaker with 4 ohm impedance (i.e. 2 woofers) will have 1/2 the output per WATT when compared to a 8 ohm speaker.  Effectively the advertised ( hopefully realistic ) db/2.83 volt rating (most common) for a 4 ohm speaker is actually 3db LESS SENSITIVE when compared to an equivalent 8 ohm speaker.  Hence a 90db 4 ohm speaker is eqivalent to a 87db 8 ohm speaker when WATTS are considered.

The lagging REAL sensitivity of a 4 ohm speaker is directly related to thermal compression.  Thermal compression is directly related to how many WATTS of electricity are dissipated in the driver voice coil.  These watts create heat.  The heat raises the DC resistance of the driver.  The input signal encounters more resistance - viola!  Thermal compression.   This happens with all drivers.

As an aside, a mature gentlemen asked me once, "where did the dynamics go?"  He remembered his old 15" JBL drivers from the 70s that really kicked, and conveyed a certain fondness for them.  I certainly agree the dynamics from big/sensitive speakers are very present.   I believe, with good support, that thermal compression is a major contributor to this issue.  There are other issues too, but I believe thermal compression is the most significant.

It might seem that I am totally against using a couple 8" drivers.  I'm not.  There are at least 3 very good reasons for using two 8" drivers.

1.  History proves their superiority.  Before the era of truly stiff cones, all drivers had some flex.  The degree of flex was often determined by the radius of the cone.  Bigger cones had more flex and sounded more muddy.  

Today most cones that appear stiff are not.     The fabric/kevlar cones (sans resin) still have some flex.   Probably the most obvious is are those conveyed by a well-kown manufacturer that purveys a "stiff cone" in one glossy brochure and a midrange from the same cone material in another glossy brochure with NO surround.  The "stiff cone" is directly attached to the frame of the driver at the leading edge.   Duh, if the cone was really stiff, and the leading edge was attached, the cone would NOT move.

In this realm a stiff cone is a stiff cone.  This is true whether the driver is 5, 6,7,8 or 12 inches in diameter.

2.  Dual woofers look really cool    .  I think they look cool anyhow.  I think the Sonus Faber Amati is a very neat looking speaker.  I have nothing against this.  The look is slim/tall and very high tech.

3.  Dual woofers have more voice coil radiating area   .  Since there are 2 voice coils there is also double the radiating area for the WATTS dissipating in the driver.  Ultimately, the amount of total surface area, and exposure to cool air,  on the driver (s) determines how well the voice coil(s) dissipate heat.  This is truly a good thing and cannot be ignored.

Summary, I think using a couple 8" woofers is a bass module is a good idea, but there are better ideas.  The theory presented above has also endured my subjective experience.

Whew, that got long.

Dave

[stvnharr]

Dave,
You took a lot of words to say what the B&W engineers said, that we think a single large driver is better than 2 smaller drivers.
My former speakers, Waveform Solos had a big driver in a big bass cabinet.   The bass went low and was very clean.   If one can handle the big cabinet, construction wise and room wise, that really is the best way to go for the best sound.

[David Ellis]

You took a lot of words to say what the B&W engineers said

Dang!  Somebody stole MY ideas again!

They obviously really didn't steal MY idea.  These thoughts should be apparant to anyone who spent a good quantity of time with loudspeaker design.  It took me about 4 years to arrive at these conclusions.

There are other issues extant too.

[stvnharr]

Now Dave..............
When you get your speaker finished the B&W engineers should be coming to visit YOU and YOUR ideas as your speaker will be better than theirs!!!!!!

[David Ellis]

I am certain that most loudspeaker manufactures could do much better.  I am also certain their reluctance has nothing to do with knowledge.  Better sound always comes at a cost.  Better drivers, capacitors, cabinets... are the primary contributors IMO.  These items also have the most impact in the accounting department. Those engineers certaily don't need to visit me.  They are brilliant guys.  

I think B&W does a very decent job with their commercial speakers.  Sure, they have shorfalls, but commercially they do nicely IMO.