[David Ellis]

Over the past 2-3 years I have experimented with a few 8" drivers in various projects.  While the results were good, none of them will be purveyed as a kit or completed speakers.  This is simply because I don't think any of them proved worthy of the time necessary for me to build cabinets around them.

My first project was the SEAS CA21REX and SEAS 27TFFC.  I was very impressed by the paper coned CA21, but not so impressed with the 27TFFC.  The CA21 is a very light paper cone midwoofer that has some cone flex, but sounds very natural/normal to my ear.  For some reason I prefer the sound of a good coated paper cone over a poly cone in the midrange.  In this regard, I found the CA21 very pleasant, smooth, and had respectable bass and dynamics.  In the realm of T/S parameters, the compromise of the CA21 was toward high sensitivity and away from a small cabinet.  For a target system project, the CA21 would provide a great foundation when driven with a simple El84 push pull tube amp.  

I found the SEAS 27TFFC a bit gritty and harsh.  I didn't really care for the tweeter.  This was my 2nd SEAS tweeter @$25, and I actaully found the H400 more pleasant to the ear - smoother.  I don't know how this could be true, but this is the way I remember it.

Next was the Focal 8k dual voice coil driver and OW1F.  During this project I learned a couple of things.  First, the stiff cone of the Focal 8K sounded cleaner than the CA21 from the first pulse of my gated time response.  This proved true during futher listening and construction.  Second, Bud Fried was right.  

Many years ago Bud Fried use the Hiquphon OW2F with a VERY simple crossover in his Studio IV speakers.  Upon first exposure to this application I thought Bud was nuts for applying that much stress to the humble 3/4" ferro fluid tweeter.  Bud wasn't nuts.  I managed to cross the OW1F around 1600hz with a very steep 4th order slope.  Upon completion I cranked up the volume and the OW1F didn't wince.  Wow!  It was with this crossover that I really began to feel confident.  I killed the 8K resonance, and had very good power handling in the tweeter.  The impedance and phase were good too.  I later learned that I wouldn't really "target" this project at anything.  Sure, it was detailed, but for the same $, a guy could purchase some SEAS W22 drivers.  These proved much cleaner in the midrange (more to follow).

Next, however, came the Meniscus 8" 838 driver and SEAS H1212 tweeter.  I chose the Meniscus 8" driver because it is one of 2 8" drivers having a 2" diameter voice coil.  Theoretically, a 2" voice coil has a larger heat radiating area and will suffer less thermal compression.  This proved very true     The Meniscus 838 has the best bass of any 8" driver in this group.  It might be better than the Scanspeak 8" drivers, but I have not spent quality time with a Scanspeak 8" driver.  Surely in the sane price realm, the 8" meniscus is an extremely good bass driver - the best I have heard in a hifi speaker.  This is THE driver for bass.  If I wanted to build a "fun" speaker for recreational listening, it would use the Meniscus 838.  If I wanted to build a good sounding speaker for my teenage kid, it would use the Meniscus 838.  If I didn't care much for symphony/jazz, I'd use the Meniscus 838.  In short, the Meniscus 838 is, IMO, the driver of choice for 99% of non-audiophile folks, and probably 50% of folks who call themselves audiophiles.  The bass from the 838 is extremely good, and the midrange is very acceptable.

During this project I also learned about the SEAS H1212.  This is a dandy tweeter!  I think this might be my new favorite tweeter around $25.  Previously the Vifa D25, and Danny Richie's silk dome tweeter were the winners, but the H1212 is very decent.  The wide polymer surround really damps the dome nicely and creates a very smooth sound.  It doesn't have the detail of the OW1, but the H1212 also doesn't commit many of the sins common to aluminum dome tweeters.  It is very well damped.  In this regard, I find sins of omission much more tolerable than sins of admission.  I like the SEAS H1212 .

My next experiment was the SEAS W22 and OW1F.  This was a serious project that I really wanted to work well.  It came out okay, but was nothing to be truly excited about.  My wife and I both thought it sounded a bit different than the 1801, but not enough different to warrant another product.  The W22 easily had the cleanest midrange of any 8" drive unit tested, but the bass was nothing special. This surprised me.  I really thought the bass from the W22 would be better.  The Meniscus 838 had better bass (bigger voice coil), an the smaller SS8545 also had better bass.  Please don't infer that the W22 bass was bad.  The W22 bass was good/acceptable, but not excellent, and only marginally better than the W18E001 to my ears.  

My very last experiment was the SEAS P21RF/P and H1212 (again).  The bass quality from the SEAS P21 from the 2" voice coil was very good, but not very deep.  I figured this would be true.  The bass was also very tight.  Unfortunately, ya' can't have everything.  The bass was not very deep.  I expected this.  The P21 is a low Q drive unit.  I suppose the bass rolloed off about 50hz.  What really surprised me about the P21 was the quality of the midrange.  It had very good midrange - possibly equal to the Focal 8k.  The SEAS H1212 continued to perform very well.

I wanted to experiment with these drivers for my personal eduction and because I truly thought something special might come out of these projects.  IMO, the only thing(s) almost special was the performance of the Meniscus 838 woofer and the SEAS H1212 tweeter.  This is a dandy driver combination that has some slam.  I could listen to these drivers for days with pop music.  They are very fun drivers and have a reasonably good amount of resolution.  The sounded very good on my workshop stereo in the basement.

However, after all of this, I plugged the 1801s into that familiar setup...  Dang they sounded good and clean.  But I learned something subjective.  This will follow in another post.

Sincerely,

[Arctos]

Hi Dave,
Have you worked with any of the drivers by Eton?  I am considering building the Eton 8.1 kit that uses the 8-800 8" woofer and 25SD1 tweeter.  I am actually trying to make a decision between this kit and Dennis Murphy's Vifa Tower.

Just curious as to your experiences and opinion.

Regards,

R

[David Ellis]

Nooo,

I haven't spent any time with the Eton drivers.  However, I have heard a few, and understand the basic construction of the woofers.

The ETON has a very good composite cone & simple motor - much like the Focal 8K.  In this regard, I think the woofers should sound very similar.  The cone resonance on the Focal 8k was slightly more forgiving than the W22.  I suspect the Eton resonance would be very similar.  The stiff cone on the Focal 8k was easily audible, and I suspect the Eton would be similar.

Given the 2 soft cones I have puttered with (Meniscus, and SEAS CA21), I have some feel for the Vifa cone too.  While paper cones have an extremely wide range of doping materials, I think the basic stiffness of the Vafa M21 unit should be very similar.  

In this regard, I think you would be extremely happy with either project, but Dennis's project should sound a bit softer, and the Eton kit should favor more inner-detail.  The preference for either project should be decided by your preference for music.  If you prefer classical recordings, the Eton project will be more pleasing.  If you prefer pop/vocals the Vifa tower will prove equally pleasing.  I don't recomment you build either project if your preference is 1970's rock-n-roll.

You will notice some distinction in my comments.  I tend to prefer a higher resolution speaker.  This is simply because it will always outperform a low resolution (i.e. paper cone) speaker with classical recordings.  However, both will perform equally well with pop music.  There are some comments on this in this string:

http://www.audiocircle.com/index.php?topic=16181

Please understand that my comments about paper cones are a generalization.  There are many varieties of paper cones.  They range from very stiff (i.e. SCC300) to very soft (i.e. pro sound 15").  The degree of cone flex obviously follows.  Also, I must admit the Scanspeak carbon fiber cones are wonderful performers, and I prefer their sound to the newer paper cone units.  This is my preference and others are welcome to disagree.

Dave

[Arctos]

Dave,
Thanks very much for your comments!!  This helps a great deal in making my decision, but I'm still a bit torn.  I spend most of my listening time (which ain't much) with classical, jazz and Cuban music.  If drivers were the only factor in my decision it would be easy and I would go for the Eton kit.  However, I have great respect for Dennis Murphy's crossover designs and don't know if the Eton 8.1 kit's crossover is as well designed.  Also, my upstream components are not that great as compared to most folks that spend time on this site so the Eton kit may only serve to affirm this weakness (AMC 3050a integrated amp and AMC CD8b CD player).

Regards,

R

[Al Garay]

For your taste in music, you should skip the Vifa towers (not enough resolution, detail) and go with Dennis' CAOW1 or the MBOW1.

[ooheadsoo]

You should be aware that the mbow1/caow1 do cost over twice as much as the vifa tower when all is said and done.

[David Ellis]

However, I have great respect for Dennis Murphy's crossover designs and don't know if the Eton 8.1 kit's crossover is as well designed

I think this is a valid concern.  Dennis indeed spends considerable time on every crossover, and has considerable experience.  However, I suspect that if the Eton kit is a factory kit then it should be good too.  The factory folks obviously have a vested interest in their products performing very well.

However, I have heard sold rumors that a few commercial folks simply used very simple and very unrefined crossover designs.  A good crossover takes time.  For commercial folks this is expensive.  Also, a great many commercial folks don't measure/Q.C. their speakers.  This might seem okay, but even the very best drivers will vary over time.  Failing to measure can be very detrimental.

Dave

[David Ellis]

For your taste in music, you should skip the Vifa towers (not enough resolution, detail) and go with Dennis' CAOW1 or the MBOW1.

Sure, if you don't listen at higher spl, then the CAOW1 or MBOW1 are most excellent projects.  They are almost double the cost of the Murphy Tower, but will provide very good resolution.

I must admit that either 8" speaker will provide a bigger sound than the smaller CAOW1 speaker.  This is nice, and I do enjoy the sound of an 8" woofer.  All things else being equal, bigger is better.

Dave

[Adarsh]

How good is 15 cm woofer for a room which is rougly 4 x 4 x 4 metres (box)?

[David Ellis]

How good is 15 cm woofer for a room which is rougly 4 x 4 x 4 metres (box)?

Well, it'd be extremely sensitive - if the surround material is physically possible.


However, my comment...

I must admit that either 8" speaker will provide a bigger sound than the smaller CAOW1 speaker. This is nice, and I do enjoy the sound of an 8" woofer. All things else being equal, bigger is better.

... addresses that a bigger driver will generally use a bigger cabinet.  This is certainly not always true.  However, when the woofer SYSTEM (i.e. woofer and cabinet) is done right, a bigger woofer system will indeed sound better.  It'll be either more sensitive, or have more bass (or both).  I encourage you to spend time with the DPC from Futtrup and fiddle with the VAS driver characteristic.

http://www.diysubwoofers.org/audiolinks.htm

The VAS is primarily a product of the surround material.  It varies depending on the durometers of squish in the surround.  Hence, the "same" driver with a different surround can/will have a different VAS.  Higher VAS will positively impact sensitivity or bass.  

After calculating the desired T/S parameter set from Futtrup's DPC, the next issue is determining if that parameter set is physically possible.  The surround, spider, magnet, cone etc etc materials may/may not be obtainable.  Certtainly cones must have weight, and surround materials must have mass & flexibility.

Your cynical query is fair    .  I really encourage you to spend some time with Futtrup's DPC .  If you remain intrigued, visit a driver builder.  The journey is quite interesting

[Arctos]

Very interesting, as I have been planning on my next project being the MBOW1!  I already have built the cabinets built for tower speakers so I am committed to either the Vifa or the Eton (FYI the Eton 8.1 kit is available from Meniscus or from Madisound, maybe this leads me to believe that the crossover is good?), but when I'm done the MBOW1 is next.  Unless, of course, I am in better financial condition, then I will build the 1801b's!!

Regards,

R

[David Ellis]

There is yet another possibility unpublished.  You certainly could build my SEAS H1212/Meniscus 8" project.  I can promise it will have the best bass.  The rest is respectable, but nothing to rave about.  The Meniscus 8" driver is darn fun.  The cabinet width should be 9-10" in 40-50 liters.

I made some copies of the crossover and can send them to you via mail.

[Al Garay]

My feeling is that if you are spending all this time and effort on DIY, then go for the better quality drivers and design.

Given that you already have the tower cabinet, I think the Eton 8.1 kit will be superior in detail and soundstage to the Vifa towers... basing this on Andy's remarks and having listened many times to his Eton speakers.

Worst case, you turn around and sell them for the cost of the kit.

[David Ellis]

I think the Eton 8.1 kit will be superior in detail and soundstage

I think so too.

My feeling is that if you are spending all this time and effort on DIY, then go for the better quality drivers and design.

I agree.  Most folks spend @30 hours on a good pair of speakers.  Given the value of most folks time, spending a scosh more makes good sense.  Then, this is a hobby for many - including me.  As such, the value of time investment probably isn't considered.  If hobby time were valued, Minnesota whitetail meat would be the most expensive meat on the planet.

[Arctos]

Well folks,
My options have just been limited, as I just found that the Eton 8-800 woofer is actually a 9" driver.  My cabinets are 8.5" wide internal and the mounting plate for the Eton driver is 8.8" diameter, thus I cannot mount it in my cabinet without atleast 2 screws going into the edge of the cabinet side, which is not acceptable to me.  It also left just .25" on each side of my woofer hole for breathing room.

My choices are now the Vifa Tower or Dave's Meniscus/Seas option.

Dave, I would really appreciate you sending me the crossover plans for your option (see email address below).  Do you think this would be a more detailed option than the Vifa?  Also, my cabinet is currently about 62 liters.  I can reduce it to about 57L without issue, but less than that would be tough.  Will this still work?  FYI, the baffle is 10.5" wide (8.5" internal, as I used 1" MDF for all cabinet walls).

Thanks,

R

rdshep@hotmail.com

[David Ellis]

Do you think this would be a more detailed option than the Vifa?

Well, it'll be close.  The Vifa has a curvalinear cone (more flexible) and the Meniscus has a stright cone (stronger).  However, the Meniscus cone is quite soft.  Also, the Meniscus 8" has a larger voice coil (more inductance).

The bigger cabinet won't be a problem  I simply suggest you tune the port by ear.  

It also left just .25" on each side of my woofer hole for breathing room.

This really isn't significant.  I thought this too when I started building speakers.  I thought breathing room was a big deal.  It's not.  On every driver there is a huge obstruction behind every woofer - the magnet/motor.  This would seem terrible, but it's not.

I just measured the Meniscus 8" and it's 8 1/4" diameter.

I don't have the crossover digital, but can mail you a paper copy.  Send me your mailing address.  

Also, if you do decide to build this project, I'd be very happy to walk you through the steps & issues.  Overall, the Meniscus 8 and SEAS H1212 is my favorite speaker for listening to all kinds of music all day long in the workshop.  It certainly isn't the last word in resolution, but is a very fun sounding speaker.

[MemphisJim]

Dave- I know you wouldn't recommend listening to purely '70's rock on the 1801's. So I have a question regarding the Meniscus 8 and SEAS H1212. You mention this:

It certainly isn't the last word in resolution, but is a very fun sounding speaker

Well, I figure '70's rock = fun and you think this speaker = fun, so I'm thinking that this may be a speaker I want to look at for generic purposes (garage/ etc). I've been wanting to build one of these kinds, but I'm not sure even where to start. The drivers are kinda pricey and the cabinets are kinda big for what I have in mind, but if you think they sound good for this application, then they may be just what I'm looking for...

Jim

[Arctos]

Thanks Dave,
I will send you an e-mail this weekend or sooner with my address and appreciate you sending me the crossover plans.  If you think there won't be much difference between your plan and the Vifa Tower I may make my decision on cost and ease of construction.

Regards,

R

[Arctos]

Dave/All,
Just an FYI that I just ordered the parts/drivers to build the Meniscus/Seas tower!!  I will let you know how it turns out, costs, component details, etc when I am finished.

Regards,

RDS

[David Ellis]

I managed to put the crossover plans and some other instructions into a word document.  Please email me for this information as desired.

Dave