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#148689 - 09/04/05 06:47 PM My poor mans PAS
batty Offline
Member

Registered: 08/30/05
Posts: 36
Loc: Kingscliff, NSW, Australia
As requested here are some shots of my Logitech z5500 setup.



First you will notice that there are only 4 speakers on the stand. When I first got the system I did a bunch of listening tests with various speaker configurations and controller settings. I found that the system lacked mid/high projection when used with any of the surround sound settings. However when switched to 'Stereo x 2' and used with the front and rear speakers adjacent to each other, the sound was noticeably better (to my ears anyway) and more balanced with the sub.



The two speakers facing the camera are Left F&R and the other two are Right F&R. The speakers and cables are permanently wired to the stand, with the connectors housed in the compartment at the bottom which makes setting up easy. The whole thing stands about 6 feet tall when sitting on the sub as shown in the photos.

The interesting thing about the satellite speakers is although they are small they are directional on-axis. When you move to the side you tend to get quite a drop-off in the mid/highs which is more than you would expect from small drivers like this. So it seemed reasonable that if the satellites were setup like a PAS and the angles were correct, you could have two speakers facing left and two facing right with the middle covered by the overlap.



As it turns out, the angled setup works well and the resulting coverage is nearly 180 degrees. Please note that while this is effective it is still only a poor mans PAS and would not claim to achieve all that a PAS can. Still, there are a couple of advantages including the ability to rotate each satellite individually if you need to hear more 'foldback' i.e. the top speaker is exactly at standing head height for my singer, while the bottom speaker is rotated slightly upwards to angle directly towards my seated head height. If we swapped sides, I could rotate the speakers the other way to accommodate. The system is run in stereo and I guess you could describe the final sound as 'partial stereo' - you get a reduced stereo effect that is better than mono and not as good as true stereo. Of course, there is no electrical summing of the signal so the stereo output of the 9000pro sounds very good indeed.



And yes, I gig-proofed the sub!

Mark

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#148690 - 09/04/05 06:55 PM Re: My poor mans PAS
SemiLiveMusic Offline
Senior Member

Registered: 08/28/04
Posts: 2189
Loc: Louisiana, USA
Hey, several of us talked about it, you DID it! That's pretty cool.

So, you don't use the 5th speaker at all?

I have two z2200 systems. Do you think I could achieve pretty much what you have there except not as many watts? Also, I wonder if I could use both subs somehow.

EDIT: Also, the question is... does it sound better as configured than two separate poles with two, split apart on stage?

------------------
Bill
Yamaha PSR2000

[This message has been edited by SemiLiveMusic (edited 09-04-2005).]
_________________________
~ ~ ~
Bill

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#148691 - 09/04/05 07:46 PM Re: My poor mans PAS
travlin'easy Offline
Senior Member

Registered: 12/08/02
Posts: 15041
Loc: Forest Hill, MD USA
Thanks Batty,

Very creative setup, and it doesn't look bad at all.

Gary
_________________________
PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!

K+E=W (Knowledge Plus Experience = Wisdom.)

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#148692 - 09/04/05 08:50 PM Re: My poor mans PAS
Scott Langholff Online   content
Senior Member

Registered: 06/09/02
Posts: 3141
Loc: Pensacola, Florida, USA
Hey Batty

Some great ideas. I think I just might have to try something like that.

I like how you gig proofed your sub. I have been thinking of doing something similar. All I have to do is find where I can get that kind of carpeting, in black hopefully and the other hardware.

Can you give any tips how you did your sub? Did you have to take any of the sub apart? YOu seem like one handy guy. I hope I could do as well as you. What kind of glue do you recommend for the carpet? Just regular glue used for carpet laying?

Thanx
Scott

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#148693 - 09/04/05 09:51 PM Re: My poor mans PAS
batty Offline
Member

Registered: 08/30/05
Posts: 36
Loc: Kingscliff, NSW, Australia
SemiLive, the 5th speaker is in a box in my garage. Theoretically you only lose about 1dB by going from 5 to 4 speakers, but in practice the sound level is overall slightly higher by using 4 speakers in Stereo x 2 mode. This is because the stereo signal is exactly duplicated by the two pairs of speakers. Someone will correct me if i'm wrong but to use all 5 satellites with the Logitech you need to have some form of surround processing of the signal. The processing creates a great soundfield, but what I am trying to do is to reinforce the stereo signal using pairs of satellites to give the mids & highs a bit more punch.

I have no doubt that using the speakers on poles in a traditional way will give you a much better stereo effect, particularly if you like to be positioned midway between the poles when you play or listen. However I am convinced that the Poor Mans PAS (maybe PMP? ) has a much better coverage, more coherent sound at all locations and is a no-brainer to setup.

I believe you could use both z2200 systems set up in a similar manner. Ideally you would use 4 speakers and one sub with two Left speakers connected in parallel and similarly for the Right, although this is not recommended without checking the impedance requirements of the amps i.e. the satellite speakers are rated at 8 ohms each, and the amps may not be capable of sustaining less than 8 ohms load. The alternative is to use both subs, either one on top of the other or side by side, then split the stereo signal from your keyboard (or mixer) to have an identical stereo input to each of the systems. You would then set the volume on each at the start, and control the master volume from the keys or mixer.

As a point of interest, I have experimented using the sub to run a pair of B&W hifi speakers (rated at 6.5 ohms) and the amps had no problem. My next experiment will be to run a couple of 10"+ horn boxes. The 10" PA speakers will have a much higher sensitivity than the Logitech satellites and I should be able to get a lot more sound level out of the system. This is only for curiosity as I am more than happy with the sound of the PMP for my gigs.

Mark

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#148694 - 09/04/05 10:47 PM Re: My poor mans PAS
Scott Langholff Online   content
Senior Member

Registered: 06/09/02
Posts: 3141
Loc: Pensacola, Florida, USA
HI Mark

I see you want to try some 10" speakers. I don't know if you've seen any of my other posts, but I use the sub only from the z5500's and 2 powered JBL Eon 10G2's and this is one excellent combination. I just plug the sub into the kb headphone jack and the 10's out of the regular left and right out of the kb. So far I have not had to use speaker stands. The JBL's conveniently tilt back and the sound bounces off the ceiling for a very nice all over sound that doesn't blast anybody in the face.

If you try them, and they are in your budget, I'll bet you stick with them. Either way, I'd love to hear your comments about your end result using 10's.

Best
Scott

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#148695 - 09/04/05 11:25 PM Re: My poor mans PAS
batty Offline
Member

Registered: 08/30/05
Posts: 36
Loc: Kingscliff, NSW, Australia
Scott, the first thing was to cut a piece of plywood for the top surface of the sub. The sub timber box is not very thick and didn't seem suitable for attaching handles. The plywood was about 15mm thick (say 1/2" or 9/16") and was glued and screwed into position. I then trimmed a little off each corner of the box to allow the corner protectors a better fit.

The carpet is actually speaker box carpet and is designed to be very flexible to bend around the shape of boxes. It came from a place called Clark Rubber here in Oz, but I guess you could get it from a similar type of store that sells rubber mats, outdoor carpet, marine carpet etc. Alternatively check out speaker building suppliers or even electronics/hobbyist stores.

The carpet is glued on using contact adhesive which you can get as brush-on or even in a spray can. With contact adhesive you normally have to apply the glue to both surfaces, wait for it to touch dry then join the surfaces, but with this speaker carpet there is no solid backing and so the carpet is quite 'breathable'. Subsequently I found no need to apply to both surfaces - just the sub. This means you can brush it on the sub and just press the carpet, one side at a time. You carpet right over the port then cut it out with a sharp knife. The carpet goes on as one long strip starting at the bottom middle of the sub and going all the way around.

The handles are screwed down using 25mm (1") countersunk timber screws. This length should be equal to the thickness of the handle plus plywood plus sub box so that the screws dont protrude inside the sub. I normally use bolts for handles but I didn't want to have to dismantle the sub to fit the nuts. With the extra plywood I guarantee these screws will not pull out.

At the moment the heatsink still sticks out at the back, but one day I will make a removable cover that clips on and off easily.

Hope this description helps.
Mark

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#148696 - 09/04/05 11:38 PM Re: My poor mans PAS
batty Offline
Member

Registered: 08/30/05
Posts: 36
Loc: Kingscliff, NSW, Australia
Scott, I reckon your EON setup would punch out some serious sound!

I am thinking of looking at the flipside and seeing how well the Logitech sub's built-in amps can power a pair of passive PA boxes. I guess for the experiment the aim would be to take it one step further and go for Stereo x 2 and use 4 passive boxes.......now where can I find a couple more 10's.......

Mark

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#148697 - 09/05/05 12:33 AM Re: My poor mans PAS
Graham UK Offline
Senior Member

Registered: 01/20/01
Posts: 1890
Loc: Lincolnshire UK
Batty. When you move to the side you tend to get quite a drop-off in the mid/highs which is more than you would expect from small drivers like this.

Nice design, I would suggest the following.

The reason for this (mid/High Drop Off) is closeness of the speakers to the rear support structure. If the support was open mesh the speakers would be able to breath, at the moment they are reflecting sound from the support frame which would also add colouration.

[This message has been edited by Graham UK (edited 09-05-2005).]

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#148698 - 09/05/05 03:17 AM Re: My poor mans PAS
Stephenm52 Offline
Senior Member

Registered: 04/13/05
Posts: 5072
Loc: USA
Batty:

Thanks for posting with your in depth description of the details.

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