question for James Tanner re: PMC surrounds

Dokter_doug · « **on:** 27 Dec 2003, 05:46 am »

In other posts on this board I have seen references to a "CC-6" centre speaker, and to a (?) WB-1 surround speaker in the works, from PMC. I can't find anything about these speakers on the PMC site. Would you care to comment?

James Tanner · « **Reply #1 on:** 27 Dec 2003, 01:33 pm »

Hi Doug,

The CB6 Center speaker will be available starting in mid January. IN fact I am showing it for the first time at the Vegas CES show in January.
It is a horizontal 3-way Center speaker with the same driver compliment as the OB1. It mates with the OB1 the IB1 and the MB2. It could also be used as rear speakers as well.
The WB1 was talked about and was an 'ON Wall" speaker using TB2 drivers. Based on customer feedback we have cancelled this and may in the future lokk at an 'IN Wall" instead.

james

Dokter_doug · « **Reply #2 on:** 27 Dec 2003, 05:30 pm »

BAH! Veto "in wall"!

WE (the royal "we" that is) need a good bipolar or dipolar speaker for surrounds from PMC...PLEASE?!

James Tanner · « **Reply #3 on:** 27 Dec 2003, 06:46 pm »

Hi Doug,

Boy did you open a can of worms with this one.
In the days of Dolby Surround Matrix the idea was to have the surrounds non-directional and therefore the use of diploles on the sides and rears to prevent localization of images. Dolby Matrix was really a MONO signal so they just spead it out around the theater.
In todays world of DISCRETE Dolby 5.1 . 6.1 and 7.1 not to mention DTS 6.1 Discrete --- dipoles are a NO-NO. I know this will fly in the face of what some manufacturers tell you but believe me when the sound is being recorded for movie and music surround systems they are directional POINT SOURCE direct forward radiating speakers ( ike PMC of course).
In fact if you pick up any SACD surround disc by Telarc you will see in the liner notes where they specifically recommend 5.1 point source speakers for playback of their recordings.
So with Movies, SACD surround and DVD A the set up is based on direct radiators not dipoles, or bipoles. Also there is no such thing as side speakers in these setups.
The studio set up can be seen in one of my Newsletters on the Bryston website.

james

Dokter_doug · « **Reply #4 on:** 28 Dec 2003, 01:20 am »

Thanks for the replies James...and I am aware of the caveats regarding surround speakers, with discrete sends vs. a decoded common channel

I have labored long and hard to set up a surround system using direct firing speakers, including using my recently demoted FB1's as surrounds (having just purchased a pair of IB1's for mains). I have a large listening/viewing room (9'x16'x25') that allows for a lot of leeway in speaker positioning as my viewing seat is about 13-14' from the screen. I have followed the "instructions" to the letter regarding speaker placement. And I have tried variations in postioning as well, with the speakers pointing directly at me, angled forward or backward (in multiple positions), and raised above ear level in order to provide some diffusion of sound.

I have listend to SACD and DVD-Adio discs in a variety of surround sound iterations, from the "studio" oriented mix of Dark Side of The Moon (with the madman running around the room) to Rachel Podger's recording of Vivaldi's 12 Violin Concertos, where the surrounds are used only to reproduce the ambience of the cathedral in which the music was played (an astonishingly beautiful recording BTW). Direct firing surround don't work for me and ALWAYS leave a gap in the soundstage between that produced by the mains, and that provided by the surrounds, and the info from the surroounds then becomes intrusive and distracting. Using the bipolar Paragigm ADP 370's as surrounds produces a seamless sound stage which sweeps embracingly forward from the front speakers, and prevents the "who's that bloody horn player honking in my right ear?" syndrome.

The local PMC dealer is going to bring out two pairs of TB2's and two pairs of LB1's in an effort to convince me that direct firing surrounds are the way to go. I've asked him to bring 2 pairs of each, because I'm prepared to face one set forward and one set backwards in an effort to reproduce the dipolar sound if the direct firing setup doesn't work.

I'll let you know how it goes.

James Tanner · « **Reply #5 on:** 28 Dec 2003, 02:03 pm »

Hi Doug,

Well obviously you have to go with the setup that works best in your room but whenever we do shows/demos from city to city we have always used direct radiators with great success. In my own surround room I have 3- MB2's (LCR) and 3 IB1's (LS,BS, and RS) plus a XB3 sub. The room is 25 by 20.
It may be that you are getting early reflections from the surrounds that is causing the holes in the soundstage. The dispersion of the speaker is very important in being able to fill in the space and provide uniform coverage of sound. Are the holes at the side walls between front and rear or at the back behind you head?
Please let me know how you make out.

james

nicolasb · « **Reply #6 on:** 28 Dec 2003, 02:18 pm »

Quote

dipoles are a NO-NO. I know this will fly in the face of what some manufacturers tell you

The current THX spec actually requires dipole surround speakers too - a pair of direct radiators for the surround back channel, with dipoles either side of the listener for the surround L&R.

Dipoles, etc., are a very individual thing in my experience - some people feel it makes the rear soundstage that much more enveloping (so it sounds as if a storm is all round you, rather than being heard through windows where the speakers are), others feel it diminishes the actual sound quality too much.

I think most people would agree a) that multi-channel music sources do not work comfortably with anything other than direct radiators, and b) that the efficacy (if any) of non-monopole speakers is strongly dependent on room accoustics.

There are a couple of intermediate solutions available - bipolar speakers are less directional than direct radiators, but not as diffuse (or bass-light) as dipoles. M&K make a type of speaker they call a "tripole" which has both direct and dipolar drivers, and hence can act as either type of speaker, or even both at the same time.

James Tanner · « **Reply #7 on:** 28 Dec 2003, 02:31 pm »

Hi nicolasb,

Yes I know the THX spec still has dipoles as part of the mix and the reason they are at the sides is to allow for the 'null' of the dipole to prevent localization. I think you are correct in that with movie sound the use of dipoles is less likely to cause problems than with music sources. The THX shift from dipoles all around to some direct radiators is an example of how the playback spec is changing relative to the recent recording methods.
I guess my point is that I have always been a big advocate of trying to reproduce in your home what the recording engineer intended you to hear. The engineering setup determines all the placement and spacial effects. If you replicate the studio setup as best you can then your chances of hearing what was intended is much more likely.
An exageration on this theme would be if you used one stereo speaker in a system which was a direct radiator and then the other stereo speaker was a dipole - I do not think your stereo image - as intended by the recording engineer - would be attainable.

james

james

Dokter_doug · « **Reply #8 on:** 28 Dec 2003, 05:46 pm »

Once again I feel like I'm swimming conversationally upstream

James, my soundstage hole appears between the front and side speakers, which are a bipolar type of Paradigm. I use Paradigm Sudio 20's as a direct firing rear speaker. Those I will replace with PMC's (probably LB1's, given my budgetary restrictions).

I have no problem with the soundstage created by direct firing surrounds when viewing movies. It is in listening to music that the direct firing surrounds just don't work for me.

Specific examples: Bipolar speakers fill in the hole between front and side speakers and allow for an experience (to whit, when listening to Riding With The King with BB King and Eric Clapton) that places me onstage with the musicians, but in the position of a front man, not sitting on the drummers head surrounded by noise. When listening to Joey DeFrancesco and Jack MacDuff's Multichannel SACD with bipolar speakers, each hammond organ (the greatest rock and roll keyboard ever invented

) is situated in a position that projects (roughly) from their respective front speaker to a position halfway along each wall (Joey on the right, Jack on the left). All Steely Dan DVD-Audio recordings have horns, "punctuating" keyboard parts, and percussion feeds emanating from the surrounds, but in a way which integrates the players with the rest of the band. When I use direct firing surrounds, in each instance, all of that surround info is extracted from its context and becomes an annoying addition coming from behind me.

Oh well. I'll keep playing around with this. I would really MUCH prefer to use PMC's all round. Thanks for the replies guys. I'm finding this interesting. Keep offering up your insights. I will endeavour to "comply" with the suggestions.

jethro · « **Reply #9 on:** 28 Jan 2004, 09:00 pm »

Quote from: James Tanner

Hi Doug,

The CB6 Center speaker will be available starting in mid January. IN fact I am showing it for the first time at the Vegas CES show in January.
It is a horizontal 3-way Center speaker with the same driver compliment as the OB1. It mates with the OB1 the IB1 and the MB2. It could also be used as rear speakers as well.

james

James,

When you say the CB6 can be used as rear speakers, do you also mean the surround speakers in a 5.1 setup ? (6.1, and 7.1 really make things confusing)
If correct, are the CB6's rotated 90 deg when used as surrounds ?

Thanks.

James Tanner · « **Reply #10 on:** 28 Jan 2004, 09:08 pm »

Hi,

The CB6 can be used for rears or backs. They would be better used horizontally though rather than vertically because you want to maintain maximum dispersion.

james