[HChi]

Hello Dave,
In one of the threads, you mentioned "Regardless of cabinet size, the W18 didn't/doesn't have the bass quality of the SS8545, Accuton C95 or Meniscus 838.  The W18 bass dynamics are very good, but not world class.  The W18 midrange is... a different story."   Also seeing your use of C95 in place of W18 in the 1801C, I am wondering in terms of midrange magic and other area, how is C95 compared to W18? What makes you switch from W18 to C95?  Also, have you had a chance to listen to C90?

Thanks,
Howard

[David Ellis]

Howard,

Good questions.  I will do my best to answer them thoroughly from a historical, business and personal perspective.  However, please realize that my comments are purely subjective, and supported by only 2 other folks.  I fully allow that others may have a different opinion on the matter.

First, I don't plan to replace the W18 with the C95 in the 1801.  The 1801B (using the W18) and 1801C (using the C95) will be offered concurrently.  The 1801B remains a very well reviewed product that continues to "produce" extremely happy customers.  As such, I don't have any plans to discontinue the 1801B using the W18 driver.  I will allow the market to determine the outcome for the 1801B and 1801C.

The 1801C's C95 drivers cost $250 more than the 1801B's W18 drivers.  As such, the 1801C kit will cost $1k.  This is a significant amount of money for a kit, and I am really not sure how the marketplace will respond.  The same was true when I offered crossover component upgrade for the 1801B several years ago.

There were several items replaced in the $100 crossover upgrade.  I replaced the the Solen capacitors with AudioCap PPMF (now Sonicap) capacitors.   I replaced the sand-cast Eagle resistors with Mills resistors.  I replaced the Solen inductors with Goertz inductors.  I really thought that about 30% of folks would fully appreciate the better components, but about 90% of folks purchased them.  I believe the customer logic was rooted in the sentiment that spending the additional $100 was a wise up-front purchase.  And, I was/am comfortable conveying that these better crossover components in a speaker have more positive impact than better speaker wire.  Hence, the better crossover components are a reasonable value for a sane hifi enthusiast.  However, the primary reason I offer them is because I use them in my personal speakers.  The same is true with the 1801C that will eventually displace the 1801B in my living room.

Speaker building remains a hobby focused on better sound in MY living room.  Yes, this does seem selfish, but this is the root of my endeavor.  My desire to share this experience with others has been fruitful for many, but the focus is on what's happening in my living room.  I do this stuff for me first.  If other folks wish to share in my hobby - great, it's a blessing for them and for me .  This is why I will eventually offer the 1801C.  I will use it in my living room.  Candidly, the 1801C isn't monumentally better than the 1801B, but the improvement does warrant my effort on another project/product.  I have experimented with many components over the years that failed to provide a better hifi/high-end value than the 1801B.  My initial experiments with the C95 were lukewarm .  After several months of dust gathering, I decided to re-address the crossover.  The results were very appealing .

The Accuton C95 has better bass than the W18, and the midrange of the Accuton C95 is marginally preferable too.  The C95 and W18 offer similar levels of detail, but the character of the C95 is less edgy and sounds more natural. The C95 almost sounds like a good paper cone driver with much more low level detail.  I now understand why folks are willing to pay $20k for a 2-way speaker from Kharma using the Accuton C95 midwoofer.  I also understand why many flagship speakers use Accuton cone drivers (Lumenwhite, Avalon, older Usher).  For many years I thought this was blatantly wrong  , but only had an 1 objective reference for this.

Mr. Linkwitz performed some great test a few years ago that are posted here:  http://www.linkwitzlab.com/mid_dist.htm  I do realize these test were not accomplished using the C95.  I also realize these tests were not accomplished in an integrated speaker.  Also, a few industry folks have conveyed that distortion tests on the Kippel Analyzer http://www.klippel.de/analyzer/default.asp makes all other methods of loudspeaker distortion testing seem archaic.  Nonetheless, these very decent distortion tests seem to indicated the Accuton C92 distortion is quite poor compared to it's peers.  I don't have a full explanation for matters in this realm.

I have never listened to the underhung C90 simply because it's T/S parameter set is unsuitable for a midwoofer.  I am certain that it sounds very good.

The only discouraging part in all of this is the cost  .  Better components are nearly always more expensive.

I will post some additional subjective comments from Ralph regarding the 1801B versus the 1801C this evening.  I'll have to dig through some email messages, but should still have Ralph's comments.

Dave

[HChi]

Thanks, Dave.  Since you have a pending 3-way project, I thought that you may have tried C90 already.
If you find Ralph's comments on 1801B and 1801C, I would like to hear them also.  Thanks again.

[David Ellis]

The hold on the 3-way project is the due to the woofer.  There is no sense buying a bunch of midrange drivers when I don't have a woofer.  Also, the improved bass performance of the C95 over the W18 in the bass region alleviates a considerable amount of my desire to build a 3-way.  The bass articulation from the C95 is really good.  It has really great punch - just like the Scanspeak 8545.  !  I have stopped "chasing" TC Sounds for a woofer.

[David Ellis]

Ralph's comments are thus:

> Dave,
>
> 1801B
> I found to be extremely detailed with a soundstage on plane or slightly
> forward of the speakers. It was excellent from the upper midrange though
> the mid-bass. It became slightly less distinct in the dilineation of bass
> notes as it moved lower in the scale of the bass range. Decay is superb,
> particularly notable when hearing the dying resonances of instruments in
> the fade out at the end of songs. In some music coherence of the overall
> presentation is lessened due to the sharp relief of the detail presented.
> Instruments can seem more forward from the whole of the music than usual
> because of an aggressive attack. It walks very close to "edgy" but never
> gets there. Realistic and accurate reproduction of the input signal with
> minimal colorations are the hallmarks of this speaker.
>
> 1801C
> This version sounds very natural in its delivery of musical tones
> sacrificing only the smallest bit of detail to the 1801B. I was more
> impressed with the smooth presentation of difficult to reproduce piano
> notes and female vocals with the "C" than the 1801B. Again superb through
> the upper mids, mids and upper bass and having a better tonal quality in
> the lower bass region though not going much deeper. The decay is wonderful
> like the 1801B revealing instrument and vocal nuance. The attack is much
> smoother. The layering and texture of music is better to my ear than the
> 1801B because it suits my preference of coherence and musicality in
> speakers. There is accuracy in the presentation a more refined delivery.
>
> Associated gear:
>
> Meridian 508.24 CD player
> Reference Line 1A Passive Preamp
> Atma-Sphere M60MkII.3 OTL amps
> JPS labs Superconductor FX interconnects and speaker wire
>
> Ralph

[Rocket]

Hi Dave,

I will watch with interest your new product (1801c) as I really like the sound of accuton drivers.  I haven't heard a hyquphon tweeters but they have a stellar reputation on the forums.

I would consider purchasing a kit from you at the $1000k mark.

Regards

Rod

[chrismercurio]

The 3-way...

the C220 Accuton seems like a likely candidate, but perhaps there is a reason you do not want to use it.

C

[David Ellis]

The 3-way...

the C220 Accuton seems like a likely candidate, but perhaps there is a reason you do not want to use it.

Generally, a bigger woofer in a bigger sealed cabinet sounds better.  I was really hoping for a sublime driver from TC Sounds, but those folks have decided to chase other matters .  Also, the only reason for me to build a 3 way is for something different/better than what is already present in the marketplace.   Wayne Wendel is brewing a speaker with the Accuton C220 that is finished.  Jim Salk already builds a very solid 3-way speaker using a 10", low sensitivity, ported TC Sounds woofer.  Both of these speakers are quite competent, and compete extremely well compared to commercial offerings at any price IMO .

However, as mentioned above, the bass from the C95 is quite decent.  I think it's on par with the SS8545.  As such, this configuration satisfies my desire for more boogie-woogie and slam very well.  Sure, an underhung 40hz F3, 90db/8 ohm sealed woofer would perform wonderfully, but this unit isn't available.

Dave

[hubert]

Hello,

I could post in the "3-way" thread but your quote is here, so...

Sure, an underhung 40hz F3, 90db/8 ohm sealed woofer would perform wonderfully, but this unit isn't available.

Yes, you are right, woofers with T/S parameters adapted to sealed boxes are very rare indeed (except some subs, with heavy mass cones...)
As you know, the main issues about sealed enclosures are their 12db slope high-pass (so maybe a gain often adapted to some rooms and placement), their best step response and no wave escaping a (nonexistent) hole.
However, a very good approach is a low tuned bass-reflex, with the entire box fitted with BAF (evidently except around the vent). Low tuning allows similar step response and curve/slope than sealed, even reducing the cone displacement at some frequencies and the large amount of BAF kills the inner resonances and main part of mid-energy escaping the vent.
I listened to such a design, a diy 3-way speaker using the accuton C220 (43 liters, Fb=25Hz Fs=27Hz) vs a similar design also using the C220 (but 50 liters Fb=Fs=27Hz, walls covered) in a large and clear room. The first design had  better bass, at same time very crisp, clear and sufficiently extended and with less resonances than the second one. These results were NOT the fact of a better suited room-gain because in the same room my 1801b (standard tuning)did not sound muddy or thick. I have also to say that...yes, this C220 gives way better bass than the 7" Seas.
 aa

[David Ellis]

Dang,

I just typed a decent response, but lost it!!! I accidentally hit the backspace key  !

Anyhow, thanks for your very thorough response.

Several years ago I performed a good a/b experiment with different size cabinets using the SS8545 midwoofer.  The smaller cabinet sounded cleaner/tighter.  The larger cabinet sounded deeper.  The port tuning was accomplished by ear and I don't remember the exact frequencies used for tuning, but the difference between the 20 and 30 liter cabinet was quite audible. I didn't really have a decisive preference regarding which sounded better, but perhaps I marginally preferred the smaller cabinet.

I have only accomplished a very crude test with cabinet stuffing that would be similar to your experience.  The woofer wasn't very good, and my test wasn't very pervasive.  Hence, my lack of difference could easily be attributed to a poor test with poor components.  Certainly the C220 is a very good woofer.  It's easily on-par with the Scanspeak 8" drivers that are very popular.

[TF1216]

Dave,

Have you given more thought on using a waveguide for the tweeter that will be mated with the Accuton driver?

[David Ellis]

Have you given more thought on using a waveguide for the tweeter that will be mated with the Accuton driver?

I am guessing that you are referring to a long pipe behind the tweeter?? 

Dave

[TF1216]

Sorry for the confusion Dave.

I was asking if you have thought about trying something like this...
http://www.zaphaudio.com/Waveguidetmm.html

We talked on the phone a while ago about my W18EX/waveguide design with a Hiquphon tweeter.

[EProvenzano]

I'm picturing an MTM using C95's and a wave guide loaded OW1.
The sensitivity would be getting up there, time alignment,.... aa

Very interesting.

[David Ellis]

Sorry for the confusion Dave.

I was asking if you have thought about trying something like this...
http://www.zaphaudio.com/Waveguidetmm.html

The sensitivity would be getting up there, time alignment,....

This is actually a very good question.  My short answer is "no", but the your questions certainly warrant an explanation.  There is considerable substance behind something that is visibly relatively simple. 

I wouldn't characterize the zapaudio creation as a waveguide.  Some of my reluctance to this terminology is due to my history repairing RADAR's.  In a RADAR, the waveguide is behind the horn.  In the zaphaudio creation, the "waveguide" is actually a subtle horn setup.  This is present to a lesser extent in the SS9900 faceplate and the very small horn surrounding the OW tweeter domes.  The effort in all of these creations is to provide some degree of directional response for the tweeter.  In the very extreme cases in pro-audio horns the response does indeed become very directional.  The potential problem in all of these creations is the potential for resonance inside the horn.  I read a very good article on this several years ago, but I don't remember the mathematical specifics.  However, the very simple truth the author conveyed is that horns are great for providing a directional response, but commensurately problematic for providing fidelity.  Hence, they are seldom used in hifi applications. 

Recessing the tweeter from the baffle may often make the crossover easier to design.  I believe this is the reason for the sloped baffle in Kharma and Avalon speakers.  It was also present in some Thiele and more expensive Hales speakers.  This may well be the case for the zaphaudio speaker.  Certainly eliminating some crossover components could be possible when implementing the recessed "waveguide" used on the tweeter.  The recessed tweeter is often helpful.  I will comment somewhat more on this below, but my general opinion is that implementing a sloped baffle to simplify the crossover should only be implemented as the very last means of improving sound quality in a loudspeaker.  There are soooo many other possibilities that cost much less money.  I believe this sentiment is shared among the propensity of loudspeaker designers.  However, there are a few marketing departments winning customers with sloped baffles in lesser speakers.  The Meadowlark audio folks used a subtle slope for many years.

If the recess places the diaphragm base of the tweeter behind the base of the woofer a time-aligned speaker is truly possible.  The acoustic centers of the drivers are very close to the base of the diaphragm in woofers and tweeters.  Adding some phase advancement to the tweeter via the filter capacitor(s) and phase delay via the woofer inductor(s) will happen in the crossover.  Therefore, the tweeter's acoustic center must be BEHIND the woofer's acoustic center.  This is the only way a time-aligned configuration can happen.  The most common way this is a achieved is a very sloped baffle such as the one found on the ACI Jaguar:



I would also like to take a minor seguay reflecting on the comments from the bottom of the review at soundstage. The full article is here:  http://images.google.com/imgres?imgurl=http://www.soundstage.com/revequip/pics/aci_jaguar2000.jpg&imgrefurl=http://www.soundstage.com/revequip/aci_jaguar2000.htm&h=300&w=128&sz=11&hl=en&start=5&um=1&tbnid=gZ4IINdN1KmLWM:&tbnh=116&tbnw=49&prev=/images%3Fq%3Daci%2Bjaguar%26svnum%3D10%26um%3D1%26hl%3Den%26safe%3Dactive%26sa%3DN

In the conclusion the author writes: 

But what you will not find is a single speaker that outperforms the Jaguar 2000 in all of these parameters. While the Jaguar 2000 may not be the clear winner in each area, it is consistently near the top, and like the Tour de France racer who doesn’t always end the day with the fastest time, the Jaguar can finish the race as the declared winner after all is taken into account.

I concur with these comments. The author/reviewer is completely accurate.  The ACI Jaguar is a profoundly good speaker when all flavors of music are considered.  I have heard that a few of these speakers can be found for about $1k.  IMO, this is a VERY good value.  Also, I am fairly certain the ACI Jaguar is a time-aligned speaker.  The tweeter is sufficiently recessed to allow this phase relationship.

There is certainly a very good theoretical basis for this configuration.  Indeed it should be advantageous.  However, sometimes things that are theoretically valid just aren't audibly significant.  It is also important to note the more recent ACI designs are not accomplished using this configuration.  The more recent ACI designs have a flat baffle.  I agree with this sentiment.

Having auditioned a few time-aligned designs, I really don't think there is any special "magic" present.  Dennis Murphy agreed on this sentiment several years ago when the 1801 was ordained.  Sure, the time aligned configuration can sound very good, but the extra work required in the cabinet is unwarranted.

So, when squeezing the last possible shard of performance from a loudspeaker a sloped baffle may help the crossover designer.  The result may be fewer crossover components or a higher impedance curve.  Either are theoretically advantageous and may provide that last small increment of audible advantage.

Dave

[hubert]

about horns or waves guides:

The potential problem in all of these creations is the potential for resonance inside the horn.

if so, don't you think this will easily be seen in the response curve?

[David Ellis]

if so, don't you think this will easily be seen in the response curve?

No, 

The resonance from the horn should be present in a waterfall analysis, but not in a response curve.  A response curve shows amplitude only.  I suppose a guy could make a guess about the resonance from the response curve based on what he thinks the response SHOULD be, but such a guess would be questionable.

Dave