[doug s.]

That's certainly interesting.  But the critical phrase is "audible diffraction."  I wonder whether he's really performed the kind of blinded, controlled A-B comparisons that would be necessary to establish what's audible and what isn't.  I'm not necessarily denying that it's audible, but it's an open question.  I wonder how many people could really hear the difference between a good speaker with its grill on and off.  There are big differences in the measured response, but I've tried that test on some people, and it was flunk city. 

i think the reason a lot of hi-end mfr's get away w/no roundovers (or small ones), is cuz many times, the drivers (especially tweeters) are off-set, making the distance wary from the edge of the drivers to the cabinet's edge, & the resulting diffraction is dispersed thruout the audible range, making it harder to hear...  but this isn't always the case - my proac tablette 8 reference signatures do an amazing disappearing act...  mebbe its cabinet is too small to impart a lot of audible diffraction ?

doug s.

[Nuance]

So do the SongTower's implement a 3/4" roundover, or any roundover at all for that matter?

[doug s.]

So do the SongTower's implement a 3/4" roundover, or any roundover at all for that matter?

from the pics, it looks like ~0.5"-0.75" roundover.  note the curve of the baffle at its edges...

doug s.

[tktran303]

I have little doubt people heard differences, but I'm surprised that Dave was not able to measure any differences.
On the other hand, I think that in the past, Dave has also noted that he could measure differences, but couldn't hear them.
Nevermind.

But it this experiemtn, one speaker is a short standmount, the other is a tall floorstander... how can we attribute the listening differences to the roundovers alone??? Surely Dave should be able to identify the confounding factor in his little experiement.

[DMurphy]

But it this experiemtn, one speaker is a short standmount, the other is a tall floorstander... how can we attribute the listening differences to the roundovers alone??? Surely Dave should be able to identify the confounding factor in his little experiement.

Why are you assuming the stand was "short."  I would assume the stand was selected to move the tweeter to the same height as it was on the floor-stander.  I still kind of doubt the source of the sound difference was the roundover, but you never know. 

[TomW16]

Just hypothesizing here.... IF the roundover makes a difference, I assume that there would be less diffraction from the baffle edges and the sounds would energize the room more evenly.  The improvement would be most pronounced in a live room and be less so in a treated room.  Years ago a company, WaveForm I believe, created an "egg" cabinet and used this justification.  Or was it the inert sound of the inside of an egg?

In any case, I imagine roundovers greater than 3/4" to be similar to offset tweeter placement on the baffle.  Likely measurable but not necessarily audible.

Who wants to set up a double blind experiment  (kidding, just kidding).

Tom

[tktran303]

Hi Dennis,

Excuse my diction. We use UK English, and the often the word "standmount" speakers interchangeably with "bookshelf" speakers.

I'm not talking about height of the stand. I'm sure the stand was selected so that that both tweeters and woofers would be at equal heights.

I'm talking about differences in baffle dimensions between speakers A (short baffle) and speaker B (long baffle).

It is erroneous to attribute the differences to a single factor (eg. roundovers), when there are other differences that have not been eliminated (such as baffle dimensions). In this case, this baffle length is the confounding factor.

regards,
Thanh.

One pair of cabinets was the 1801 floorstanding version having square edges. 
The other cabinet was the 1801 stand mounted version with a 1 1/2" radius roundover.

[DMurphy]

I certainly agree about the need to control for other confounding factors in a scientific experiment.  But in this case, the extra baffle length beneath the woofer in the stand mount actually has very little impact.  I've conducted my own experiments on that variable, and it's the cabinet width that will be the controlling factor in baffle step and other diffraction effects.  Frankly, I find the whole description of that roundover experiment a little difficult to fathom.  Dave says the square-edge vs. 1.5" roundover had no impact on measurements.  That just couldn't have been true.  I've already given the link to my own measurements that show the dramatic effect on measurements of 3/4" roundover vs none.  I don't think that's an open question, either in theory or in practice. What is unsettled is the audibility of it all.

[tktran303]

Hi Dennis,

OK. Now that we're on the same wavelength...

In the process of converting a bookshelf speaker to a floorstanding speaker, my own measurements show that there is a 1dB lift below ~500Hz when extending a baffle length from 7.5"x15" to 7.5"x40" (WxL).
Whether it is significant or audible, that is another matter, but I've noticed this finding observed by fellow DIYers with much more comprehensive measurement suites than myself (eg. Troels Gravesen/Denmark), as well what the CAD software predicts (Baffle Diffraction Simulator etc). The exact frequency where it starts to occur, and degree of lift is dependant on initial and final baffle dimensions. Of course, accurate measurements below 300-400Hz is difficult to do indoors, so the conditions must be right to observe this effect.

If you recall, Dave has also previously stated that baffle roundovers created measureable differences, but it wasn't audible. (Regarding 1801F vs 1801, see Post 3 of of http://www.audiocircle.com/index.php?topic=7577.0).

1.  There is a positive aesthetic, measurable and theoretical impact of a nice baffle edge roundover.

2.  It ain't audible.

Now he is stating the opposite. That's fine with me.

I have no doubt that Dave indeed hears what he hears, however I do not agree with this interpretation of his findings, or these conclusions regarding causality.

Anyway, back to the Songtower RT's- I like the look of them with the alu baffles.
I don't care if it has roundovers or not, I'm sure it sounds great nevertheless.

[jonwb]

to my count 14 posts related to this round-over v. no round-over v. bigger/smaller round-over... 

I think its safe to say this thread is now thoroughly off-topic...  Albeit interesting, perhaps there is a better place for this discussion and members can get back to the discussion on the SongTower RT.

[DMurphy]

Well, it is a little off topic now, but it probably won't be for future offerings.    Anyhow, I doubt that people with anything to add on the RT ST are being discouraged by our babble.  I think we're all waiting to see what Frank has to say about his anyhow. 

[doug s.]

I have little doubt people heard differences, but I'm surprised that Dave was not able to measure any differences.
On the other hand, I think that in the past, Dave has also noted that he could measure differences, but couldn't hear them.
Nevermind.

But it this experiemtn, one speaker is a short standmount, the other is a tall floorstander... how can we attribute the listening differences to the roundovers alone??? Surely Dave should be able to identify the confounding factor in his little experiement.

in dave's 1801c thread, i specifically asked him about whether comparing stand-mount to floor-stander might not be an apples-to-apples comparison; this was his response:

"...Your query is reasonable, and I have considered this.  Unfortunately, it is not he controlling variable.  I have spent many hours with the 1801B in floorstanding (square edged baffle) and stand-mounted configurations (3/4" roundover).  Several folks have performed this comparison.  The difference was extremely small/non-existent...."
http://www.audiocircle.com/index.php?topic=50882.msg509738#msg509738

doug s.

[ThorsHammer]

Well, going a little more off topic I've got a "good news" "bad news" story....the bad news -I got all pumped a little while back thinking I had bought Bruce's H2's that were for sale, we had been corresponding and I made the full offer so I just assumed I was in. Turned out he had an above full price offer from a local buyer ahead of mine...no H2s for me.

The good news - it motivated me to get off my @ss and finally place my order for the SongTower RTs and a SongCenter. So, in about 30 days I finally get to hear what all the buzz is about...and, I am jacked.

Just wanted to again thank Nuance, funk and all you other poor Salk junkies for giving me so much quality info. If it wasn't for the "In search of the perfect speaker" thread I probably never would have even heard of Salk...and the feedback from all the owners sealed the deal.

[Nuance]

Thor - I guess that's bad and good news.  Either way, I am glad you're joining the Salk family.  And thank you for the kind words; happy to have helped.   

I look forward to your impressions!

Frank, when will you be spending some quality listening time with the RT's?  I can't wait to get your impressions! 

[robinje]

The pictures of the SongTower RT's in Pau Ferro Rosewood at the top of this thread were just too much to take.  I just ordered a pair finished with the same veneer!   aa

I have mostly been a lurker here, with occasional inquiries about the Veracity QW and HT2.  But, with an optional ribbon tweeter now available in the lower cost SongTowers, I could not resist Salk speakers any longer.  Based on all the positive remarks on this forum and elsewhere regarding the SongTowers and Salk speakers in general, I am optimistic that these will be just what I am looking for. 

Here's what I'll be feeding tunes to the SongTowers with:

VPI Scoutmaster w/Dynavector XX2Mkii
Rega Saturn
Modwright SWP9.0 Sig. phono preamp
Modwright SWL9.0 Sig. line stage preamp
Wyred 4 Sound SX500 monoblock power amps

[carusoracer]

The pictures of the SongTower RT's in Pau Ferro Rosewood at the top of this thread were just too much to take.  I just ordered a pair finished with the same veneer!   aa

I have mostly been a lurker here, with occasional inquiries about the Veracity QW and HT2.  But, with an optional ribbon tweeter now available in the lower cost SongTowers, I could not resist Salk speakers any longer.  Based on all the positive remarks on this forum and elsewhere regarding the SongTowers and Salk speakers in general, I am optimistic that these will be just what I am looking for. 

Here's what I'll be feeding tunes to the SongTowers with:

VPI Scoutmaster w/Dynavector XX2Mkii
Rega Saturn
Modwright SWP9.0 Sig. phono preamp
Modwright SWL9.0 Sig. line stage preamp
Wyred 4 Sound SX500 monoblock power amps

That Rosewood is very nice. Makes you wish you could have a collection of different speakers in various veneers
Nice system.

[funkmonkey]

The good news - it motivated me to get off my @ss and finally place my order for the SongTower RTs and a SongCenter. So, in about 30 days I finally get to hear what all the buzz is about...and, I am jacked.

Just wanted to again thank Nuance, funk and all you other poor Salk junkies...

Congrats, Thor.  I am sure you will be a very happy god of thunder when they arrive! 
Cheers buddy
-Funk