[randog]

Just so ya know we're talkin' about ya:  

http://www.audiocircle.com/index.php?topic=1947

Randog

[Ravi]

Randy, I'll let Dave speak for himself, but here is my opinion on the matter:

Rick designed this per a special customer request, so I don't think he was trying to 'outdo' the 1801s, but fill the customers need.  Whether the need is met or not, we'll see.

From my experience, the fewer the drivers, the more coherent the sound is to me.  Some people may like the increased spl capability of the mmt, but IMO a well designed 2way is hard to beat for coherency and transparency.  

But I'll reserve absolute judgement till I hear it.  The Seas W18s aren't exactly cheap at $155USD a piece, so adding two more for the pair is adding over $300 just in driver cost over the 1801s.  I think these speakers fulfill different needs.

[randog]

Agreed. My only interest is with a center channel application. I mean, hell, I've got a pair of 1801's with the final screws going in place as we speak!  

In fact, I don't even *want* to hear these MMT's unless someone kicks one of them over first!  

Randog

[Ravi]

"In fact, I don't even *want* to hear these MMT's unless someone kicks one of them over first!"

Hehe, I like that  

I agree, the center channel application is the only way I can see justifying the expense of two W18s per speaker.  

Also good for people to know that if they want more SPLs, adding another W18 won't really go very far, as its the OW1 thats the limiting factor for volume.  If you want Dave's 1801s to go really loud, just pad the tweeter with a resistor (this has no affect on sound quality if you use a highquality resistor like Mills), this will take the strain off of the tweeter at high volumes, and will allow you to crank these babies to extremely loud levels.  I was amazed how much power a single W18 can take simply by padding the tweeter a bit.  I was able to fill a 37 X 35ft room with loud, crystal clear sound, and the 1801 didn't even break a sweat.  The extra padding on the tweeter actually sweetens the sound even more, so it has multiple benifits.

[randog]

OK, this is great info for the tweaks archives and I can't let you get off that easy! Can you be more specific about 'padding' the tweeter? In layman's terms? This is a new one for me.

Thanks,
Randog

[Ravi]

Padding the tweeter simply means to add a resistor in series with the tweeter's + terminal.  An easy way to experiment what level you want to set the tweeter padding is to simply use a resistor (at values ranging from .5ohm to 3 ohm) to 'jump' the positive woofer and positive tweeter binding posts.  Use a regular wire for jumping the negative woofer and negative tweeter terminals.  Then,  connect your speaker wire from your amp to the woofer binding posts.  Change the resistor values until you find the ideal balance.  Once your happy with a value (say 2.5 ohm), simply remove the tweeter and solder the resistor behind the + terminal.

I'm not the greatest at explaining things, but I hope this helped!

[randog]

Perfectly understood. Nice job... thanks.  

[EProvenzano]

I've done exactly what Ravi is describing with my 1801's.
I also experimented with 1-3ohm resistors with the purpose of making my poor recordings more listenable. I found that the 1ohm resistor just took a touch off the highs and lowered the fatigue I was experiencing with some crappy disks.
I'd like to caution, however, that padding the tweeter will not buy you much volume. I'd be willing to bet that the 3ohm resistor gave me a 2db drop in the tweeter. This isn't getting you much extra head room IMO.
I don't want anyone having a false sense of security with this tweak, and accidentally start over driving their 1801's.

Enjoy,
EP

[Ravi]

Eproven,

Thanks for bringing some sanity back to this discussion.  Yes, you're right.  What I meant was that by bringing the tweeter down about 2 to 3db, this gives the W18 a chance to really open up and show its stuff, and at this volume level, I really doubt anyone will find the 1801s not loud enough, unless you're throwing a block party.

[Rick Craig]

Randy, I'll let Dave speak for himself, but here is my opinion on the matter:

Rick designed this per a special customer request, so I don't think he was trying to 'outdo' the 1801s, but fill the customers need.  Whether the need is met or not, we'll see.

From my experience, the fewer the drivers, the more coherent the sound is to me.  Some people may like the increased spl capability of the mmt, but IMO a well designed 2way is hard to beat for coherency and transparency.  

But I'll reserve absolute judgement till I hear it.  The Seas W18s aren't exactly cheap at $155USD a piece, so adding two more for the pair is adding over $300 just in driver cost over the 1801s.  I think these speakers fulfill different needs.

You really made some good points. All designs have tradeoffs and what route you take is based on personal listening preferences. I tend to like 3-ways better but some people like the simplicity of a 2-way. It's much easier to get good results with a MT versus a MMT or 3-way; however, after doing so many 2-way designs I find most of them just plain boring.

[Rick Craig]

"In fact, I don't even *want* to hear these MMT's unless someone kicks one of them over first!"

Hehe, I like that  

I agree, the center channel application is the only way I can see justifying the expense of two W18s per speaker.  

Also good for people to know that if they want more SPLs, adding another W18 won't really go very far, as its the OW1 thats the limiting factor for volume.  If you want Dave's 1801s to go really loud, just pad the tweeter with a resistor (this has no affect on sound quality if you use a highquality resistor like Mills), this will take the strain off of the tweeter at high volumes, and will allow you to crank these babies to extremely loud levels.  I was amazed how much power a single W18 can take simply by padding the tweeter a bit.  I was able to fill a 37 X 35ft room with loud, crystal clear sound, and the 1801 didn't even break a sweat.  The extra padding on the tweeter actually sweetens the sound even more, so it has multiple benifits.

I would advise against adding an extra resistor. You may prefer the results; however, the added resistor will change things other than just the tweeter level. A better alternative is to change the values of the resistor(s) in the tweeter section of the crossover as Dave has suggested.

The OW1 will play quite loud but any 3/4" dome will start to show some compression before a 1" dome will. A single W18 is plenty for most rooms but being able to move more air in the low frequencies is a big benefit of adding a second woofer.

[David Ellis]

Emilio and I concur on this issue.  Thanks for responding Emilio.  

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

I've done exactly what Ravi is describing with my 1801's.
I also experimented with 1-3ohm resistors with the purpose of making my poor recordings more listenable. I found that the 1ohm resistor just took a touch off the highs and lowered the fatigue I was experiencing with some crappy disks.
I'd like to caution, however, that padding the tweeter will not buy you much volume. I'd be willing to bet that the 3ohm resistor gave me a 2db drop in the tweeter. This isn't getting you much extra head room IMO.
I don't want anyone having a false sense of security with this tweak, and accidentally start over driving their 1801's.
 

I think it is great that you guys can share your own experiences and solutions regarding this issue!

Further, when swapping individual resistors there is some phase shift in the tweeter.  Maintaining the same circuit impedance via Thenvian' equivalents will assure no phase shift but requires swapping both resistors.  Explaining all of this gets VERY long and would essentially force me to re-write a few small sections of my electronics text.  I would rather not do this.  Please see "The Art of Electronics" by Horowitz for further explanation.  Swapping one resistor will effect phase, but small changes result in a very small phase shift.  It is measurable, but to my ears it is not audible.

The range of resistor swapping you gents are working with fall within a "range" of tolerance that mantains a decent phase and impedance relationship between the two drivers.  Some folks claim to hear a perfect phase relationship at the drivers.  I have not tested one of these guys, but suspect these folks are overly optimistic about their hearing.  I certainly don't hear anything change when moving my dead up/down 10" from the tweeter axis of the 1801.  This movement effects the even arrival of the wave front from the tweeter and woofer at the listenig position.  Moving off the tweeter axis of the 1801 will mess-up the phase, but I sure can't hear it.

One manufacturer claims that his speakers should be tilted rearward until the image "snaps" into focus.  At this point the drivers and listener are at perfect phase and the magic happens.  Frankly, I don't hear it.  

Can anyone hear this effect?  Can you guys hear phase?

Dave

[audiojerry]

Can anyone hear this effect? Can you guys hear phase?

Dave

I thought I heard it once
I too, have a hard time hearing small (to large) differences in absolute phase vs left/right channels being out of phase.

There has always been much emphasis placed on time coherent speakers from folks like John Atkinson, and Dunlavy, and that 1st order crossovers must be used to be time coherent, and that the speaker baffle must be angled, or that the drivers voice coils must all be in the same vertical plane, but I could never hear this. I'd like to find someone who can demostrate their ability to hear differences in time coherency.

[Pedro]

I will not claim I can easily hear phase differences between drivers, but I can categorically state that I hear BIG differences in phase, transient response, soundstaging and imaging between full range speakers and multiway, even those with 1st order XO's, time and phase coherent, aligned baffles etc.

There is a certain "rightness" with FR speakers that is plain missing in multiways. But there is also a certain "WRONGNESS" with FR that make them hard to live with, such as peakiness, roughness in the upper midrange, rolled off highs (not necessarily a bad thing) and directionality.

Well done 1st order speakers retain SOME of this "rightness" to my ears

After many years as music lover and audiophile and more recently a loudspeaker DIY, I have concluded that "ideally' the less drivers and the less XO the better. I have been searching for the perfect combination for a looong time and have gotten closer since I've been rolling my own.

It is hard to persevere given the awful state of commercially recorded music, the incredible amount of hype in the audio market place and audiophiles that have forgotten what live music sounds like.

Just my two cents worth


[/quote] The range of resistor swapping you gents are working with fall within a "range" of tolerance that mantains a decent phase and impedance relationship between the two drivers.  Some folks claim to hear a perfect phase relationship at the drivers.  I have not tested one of these guys, but suspect these folks are overly optimistic about their hearing.  I certainly don't hear anything change when moving my dead up/down 10" from the tweeter axis of the 1801.  This movement effects the even arrival of the wave front from the tweeter and woofer at the listenig position.  Moving off the tweeter axis of the 1801 will mess-up the phase, but I sure can't hear it.

One manufacturer claims that his speakers should be tilted rearward until the image "snaps" into focus.  At this point the drivers and listener are at perfect phase and the magic happens.  Frankly, I don't hear it.  

Can anyone hear this effect?  Can you guys hear phase?

Dave[/quote]

[David Ellis]

Your comments about full range drivers does make very good sense.  Honestly, I have never taken the time to sit and listen to a good full range speaker.  I have a couple respectable drivers in my basement though.  One of my fellow DIY guys said these are actually very respectable sounding.

I appreciate you taking the time to offer this insight.

Can you recommend a very good full range speaker to audition.  I'll be driving across the USA and will likely have the opportunity to hear one somewhere.  I realized these things are pretty rare.  

I listened to a Tannoy Churchill once.  It had a cool sound too.  I liked it - a lot!  I didn't know if it sounded "right", but it was easily the best 300b SET setup I have neard.  This speaker obviously has a crossover though.  Hm, I have a question for you.

Pedro, do you think the cool full range sound could be partially atributed to the synergy between sensitive speakers (low impedance phase too) and SET amps?  Do full range systems still have that "right" sound on a SS amp?

Thanks for your input.

Dave

[audiojerry]

Pedro, thanks for contributing your insights. I am in strong agreement with you regarding a minimal of crossover electronics. I have gone round trip on the speaker merry-go-round several times owning many dozens of speakers and auditioning many more going from monitors to full range and back again with dynamic drivers, electrostats, ribbons and hybrids.

I have slowly been developing and evolving my listening skills and personal values regarding speaker virtues, and over time I am realizing that the strongest virtue in a speaker for me is transparency. More than than bass extension, dynamic range, or power handling, I cannot accept a speaker that lacks transparency.  I have owned some outstanding full range speakers including Vienna Acoustics Mahlers, B&W 801, Dunlavy SC-IVa, and more, and while I may sometimes miss some of the things that those speakers offered, I am totally addicted to the transparency, intimacy, and musicality of my small monitors, which are ProAc Response 1SC's. This week I just acquired a pair of Dynaudio 1.3SE, and so far have been very impressed by them as well.

Some of what I'm saying may sound conflicting, because I cannot verify if the crossovers of either the ProAc or Dynaudio is 'minimalist', but I think the fact that there are only two drivers with a crossover point set very high is crucial to producing a clean sound. To me lower crossover points degrade the smoothness of the very important upper midrange lower treble region of the music, and a much smaller cap and inductor is required. When you go to a 3 way driver you must insert another crossover into the mix with the need for even larger inductors and caps. Regardless of their quality, these crossover components will still compromise transparency.

By mentioning Dynaudio and ProAc, I'm not trying to run down Dave's 1801. I've heard it at both Jackman's and my home, and it is an excellent speaker, and definitely transparent. I think it has potential to be even better, and system and room matching has a big effect on results. In addition, value-wise the 1801 is a lot more affordable.  I believe Dave is a very fair and open minded guy who understands my position, and besides, this is his forum. If he wants to remove this post, it's his choice.

I plan on posting this subject of speaker design theory as a general topic in the Audio Circle Forum, but I'd like to get Dave's thoughts on this.

PS: Dave, if you are planning to travel to audition full range speakers, I am helping a dealer/owner in the Madison, Wisconsin area sell his pair of mint Tannoy Churchill's with the Super Tweeter option. There is an ad in audiogon: http://cgi.audiogon.com/cgi-bin/cl.pl?spkrfull&1056814929
They are awesome....and transparent.

[Val]

Dave, the speaker you have to hear is the Lamhorn, one I almost purchased years ago, and I understand the current version has been improved. Be sure to listen to one with the Reps 1 full-range driver, the best (and most expensive) of its kind. Robert Lamarre is almost as nice as yourself and he will surely recommend what dealer to visit. I think he has dealers in California, Ohio and Massachusetts:

Lamhorn Site

Tannoy Churchills (great name!) aren't full range but a conventional driver with an axially-mounted tweeter, similar the new KEFs and Thiels. Tannoy has been using this type of mounting for many years.

Val

[David Ellis]

I don't know anythining about the Lamhorn units, but will be driving through Ohio this month.  Hopefully I'll have time to stop in Dayton for a listen.  

His drivers appear to be well constructed.

Yes, I do know that Churchill speakers are not a true full-range speaker.  They do have that nice groovy sound though - very addictive.  I can see why guys like it.

Dave

[Pedro]

Your comments about full range drivers does make very good sense.  Honestly, I have never taken the time to sit and listen to a good full range speaker.  I have a couple respectable drivers in my basement though.  One of my fellow DIY guys said these are actually very respectable sounding.

I appreciate you taking the time to offer this insight.

You are welcome and thanks for listening

Can you recommend a very good full range speaker to audition.  I'll be driving across the USA and will likely have the opportunity to hear one somewhere.  I realized these things are pretty rare.  

I don't get around much anymore auditioning commercial designs (perhaps I should) so i cannot comfortably recommend anything with any degree of credibility. But I'll keep you posted.

I have a question for you.

Pedro, do you think the cool full range sound could be partially atributed to the synergy between sensitive speakers (low impedance phase too) and SET amps?  Do full range systems still have that "right" sound on a SS amp?

I've had three all tube setups (a monster ARC, a humble Jolida and an even humbler home made effort), they were all superior to SS in my opinion, all things being equal. And yes, I think SS and full range still show that "right" sound. As for SET amps Iv'e only heard two of them at lenght with a Lowther based system and a Brentworth? system. The Brentworth sounded fantastic, the Lowthers are not my cup of tea, but they both had a sonic presentation that was right to my ears. [/quote]

Regards

Pedro

[Pedro]

Pedro, thanks for contributing your insights.

And thank you for yours

I am in strong agreement with you regarding a minimal of crossover electronics. I have gone round trip on the speaker merry-go-round several times owning many dozens of speakers and auditioning many more going from monitors to full range and back again with dynamic drivers, electrostats, ribbons and hybrids

We have traveled the same path

I have slowly been developing and evolving my listening skills and personal values regarding speaker virtues, and over time I am realizing that the strongest virtue in a speaker for me is transparency. More than than bass extension, dynamic range, or power handling, I cannot accept a speaker that lacks transparency.

We part company here as I feel lack of real dynamic range is one of the barriers separating us from quality reproduction. Not sure what you mean by transparency as applied to sound, could you elaborate?

I am totally addicted to the transparency, intimacy, and musicality of my small monitors, which are ProAc Response 1SC's. This week I just acquired a pair of Dynaudio 1.3SE, and so far have been very impressed by them as well.

I have a dealer nearby that handles ProAc, I will check them out and the Futures series.

Some of what I'm saying may sound conflicting, because I cannot verify if the crossovers of either the ProAc or Dynaudio is 'minimalist', but I think the fact that there are only two drivers with a crossover point set very high is crucial to producing a clean sound. To me lower crossover points degrade the smoothness of the very important upper midrange lower treble region of the music, and a much smaller cap and inductor is required. When you go to a 3 way driver you must insert another crossover into the mix with the need for even larger inductors and caps. Regardless of their quality, these crossover components will still compromise transparency.

I read somewhere that the 1SC's have a high order XO. I take this to mean 1st order? I'm partial to most of what you say except for that "dynamic range" thingie. Very difficult (if not impossible) to achieve in a two way to the degree I think is required for realism without compromising other important factors. What to do?

Regards

Pedro