[Sparks]

I've been wanting to get 3 matched speakers for my music\ht room for over a year.
I've considered DIY, retail, direct, used, you name it.
A little while back, I was having a cocktail and surfing the speaker sites.
I really liked the Veracity HTC configuration but since I use FP I want a vertical rather than a horizontal cabinet.
After thinking about it for a couple days, I e-mailed Jim to see what he thought of a vertical Veracity HTC.
To make a long story not quite so long,
Jim and Dennis Murphy are going to modify the HTC into a vertical config.
The crossover will be tweaked and the G2 replaced by the LCY to allow closer placement of the W18 drivers.
I've got to admit I'm kind of excited about it. I know buying speakers without auditioning is usually a no-no but I've got a feeling this will work out fine.
What do you guys think?
BTW, I did not see the other speaker idea on this circle prior to contacting Jim.  

[J North]

great service from the Salk guys!

one question is are you going to put the LCY into the L&R as well??

FWIG, it's pretty important to have the same voicing in HT, especially across the front.

[Sparks]

Yup, all 3 speakers are identical.

[jsalk]

Sparks -

I currently offer a Veracity HT1 and Veracity HT3.  Your design will be offered as a Veracity HT2.  Dennis is working on the crossover as I write this.

It just so happens that we recently designed a speaker using the LCY tweeter and the Extremis 6.8 midwoofers in an MTM arrangement (I need to get a web page up on this design - if I could just find the time).  At any rate, when I cut the test cabinet for that design, I cut the rebates for the 6.8's a little on the large side.  Wouldn't you know it, the W18's fit perfectly.  So no new test cabinet was required.

Your HT2's will be stand-mounted, sealed monitors.  The HT2's will be available in that configuration as well as a floor-standing, vented version (very similar to the LCY/Extremis speaker I am calling the EXT, but with an enhanced cabient design).

As for substituting the LCY for the G2, this is only being done in order to mount the W18's closer together than would be possible with the G2.  While the LCY has slightly enhanced dispersion and upper extension as compared to the G2, there will be no audible difference between the two tweeters.

I am looking forward to this design.  It will be a keeper!

- Jim

[DMurphy]

HI.  In theory, this should be a very nice sounding speaker.  I did a floor-standing MTM version of the 1801 (0W1 tweeter instead of a ribbon), and liked it very much.  Excellent bass from the dual W18's, and not at all harsh.  Although the LCY will allow a closer spacing of the woofers, the main advantabe will be a lower crossover point, which is very important in an MTM.  As I recall, I was able to get the LCY down to around 2100 Hz in the Extremis.

[brj]

As for substituting the LCY for the G2, this is only being done in order to mount the W18's closer together than would be possible with the G2. While the LCY has slightly enhanced dispersion and upper extension as compared to the G2, there will be no audible difference between the two tweeters.

Is the LCY dispersion "slightly enhanced" in the vertical direction, horiztonal direction, or both?

If horizontal, that might be attractive for some people looking for a wider sweet spot (although room treatments would be an even better idea in that case).


Does the LCY pose any advantages in terms of the crossover design?

[jsalk]

brj -

See Dennis' comments above.

The LCY dispersion is "slightly" enhanced on paper.  But as a practical matter, there would little, if any, audible difference.  The G2 dispersion is very good both vertically and especially horizontally.

As for frequency response, the G2 is down 3db at 40,000Hz whereas the LCY is down 3db at 60,000Hz.  But, of course, you cannot hear these frequencies so, from a practical point-of-view, there is no audible difference here either.

When we first started playing with the LCY, we talked about replacing the G2 in the Veracity line in general.  But we came to the conclusion that there would be no audible benefit to doing so, especially considering the added cost and the fact that all the crossovers would have to be re-worked  The G2 is an incredible driver to begin with.

If we were starting from scratch, perhaps it would be a consdieration. But it is certainly not worth changing a proven design as there would be no audible benefit.

- Jim

[ctviggen]

Is that theoretical or actual frequency response?  If it's actual, how do you measure it?  I can see using a sine wave generator for input, but most microphones aren't calibrated past 20kHz.

[brj]

Thanks for the response, Jim!

Please understand that my questions merely reflect curiosity, and not any concern about the Veracity design as it currently stands.  I just like to understand what drives various design trade-offs.

For the record, however, was the "slight dispersion enhancement" in the vertical or horizontal direction, or both?

Regarding Dennis' comments about the lower crossover point, I seem to recall that Seas W18EX plays (cleanly and flatly) a bit higher than most other mid-range drivers.  Thus, my understanding is that the lower crossover point enabled by the LCY would not pose any advantage on the Veracity series speakers, especially as they are not MTM designs.  (Although please feel free to correct me if I'm wrong.)

Consequently, the question about the crossover was to determine if the LCY tweeter enabled a simpler crossover, which might balance out the driver cost issue and/or sound better in total (driver change + crossover).  I haven't seen a plot of the HT3 frequency response, but the HT1 response (G2 + W18EX) on your website is remarkably flat already.  While I don't know what phase or time alignment issues might crop up with such a tweeter/crossover change, I'd be impressed indeed if an audible improvement could be achieved!

Is that theoretical or actual frequency response?  If it's actual, how do you measure it?  I can see using a sine wave generator for input, but most microphones aren't calibrated past 20kHz.

Naval sonar system!

[brj]

the main advantabe will be a lower crossover point, which is very important in an MTM.

Dennis, would you mind educating me a bit?  Why is a lower crossover point important for an MTM design?

Thanks!

[jsalk]

Bob -

The -3db at 60,000Hz is theoretical as supplied from the manufacturer.  This upper limit has no bearing on speaker design as it is inaudible.  It does provide some insight as to the driver's ability to reproduce low-distortion detail in the upper audible frequencies.  But other than that, it has no practical impact.

- Jim

[DMurphy]

the main advantabe will be a lower crossover point, which is very important in an MTM.

Dennis, would you mind educating me a bit?  Why is a lower crossover point important for an MTM design?

Hi  That's because of an MTM's uneven vertical dispersion due to interferrence between the two woofers.  On axis, the two woofers will image in the center at the tweeter position, and the crossover is designed to give flat, or whatever contour you want, on axis.  As you move to the sides, the only thing that will change is the inherent horizontal dispersion of the drivers, and the response should stay fairly flat if the designer has done enough homework.  But Euclid gets into the act as you move above (or below) the tweeter axis.  The higher you go, the greater will be the difference in the relative distance of the two woofers, since they are mounted vertically and apart from each other.  This will change the relative arrival times from the two woofers, and that will affect phase.  The two woofers will start to get out of phase with each other, and frequencies in the midrange and upper midrange will start to cancel.  I have a measurement of that here: http://murphyblaster.com/content.php?f=gem_mod.html     Go to the bottom of the page.        That doesn't change the on-axis response, but it does affect the overall room power response, including all reflected sound. And it affects the sound when you stand up.  The way to minimize (but by no means eliminate) the problem is to get the woofers as close together as possible, so the relative distances don't change as much off-axis vertically,  and to cross as low as possible to narrow the range where the woofers will interact.  

Thanks!

[brj]

Thanks for the explanation, Dennis!  It made a great deal of sense.

The plot you mentioned is quite illuminating, although it would be helpful to mention how far off axis the microphone was during measurement (distance and angle).

Are you aware of any published plots that show the on and off axis response of the same MTM speaker crossed over at different frequencies and/or with the woofers spaced at different distances?  Nonetheless, it seems that the greater efficiency of an MTM design will definitely involve some level of tradeoff for those desiring a larger sweet-spot.

Thanks again!

[DMurphy]

Hi  The plot was taken at standing height, and at a little over 1 meter, which will exaggagerate the effect, since the difference in relative woofer position will be less the farther back you go.  But I can't measure at a normal listening distance.  Sorry--I'm not aware of any comparo plots such as you mention.

[Sparks]

Your design will be offered as a Veracity HT2

Cool!

Personally, I'm hoping for the open, airy. spacious sound with detail and neutrality.
Able to listen at low levels and of course crank it up and remain clean and non-fatiguing.
You know, rosin, horse hair, gut strings, .50 cal machine guns,  everything.  

[jsalk]

sparks -

Personally, I'm hoping for the open, airy. spacious sound with detail and neutrality.
Able to listen at low levels and of course crank it up and remain clean and non-fatiguing.
You know, rosin, horse hair, gut strings, .50 cal machine guns,  everything.  

You should have no problem.

- Jim

[Brucemck]

The measurement example of standing response was very instructive!

Dennis, how far "off axis" is meaningfull? 5 degrees? 10? 20?

(And, I assume it's lower if the crossover is higher?)

[DMurphy]

Dennis, how far "off axis" is meaningfull? 5 degrees? 10? 20?

(And, I assume it's lower if the crossover is higher?)[/quote]


All I can really say is that you will definitely notice the change in frequency balance if you stand up at a normal listening distance.  That said, the effect is not at all disagreeable.  The sound just has less presence--it's not like you lose all kinds of higher frequency information, as you would if you moved off-axis listening to an electrostatic panel.  

I've pretty much finished the crossover for the floor-stander Veracity MTM.  The combination of the W18 and LCY tweeter makes for an extremely open and detailed sound.  I suspect the sound is notably more open than on the similar Thor MTM, which uses the Seas Millennium tweeter.   We'll have to optmize the box tuning (I'm using one tuned for the Extremis woofer), but the hard work is done.  I hope to get to the sealed monitor version next week.

[Sparks]