[Rick Craig]

I finally have a minute or two and wanted to respond to some things said here, some of which is very misleading.

This is a common misconception and I've seen other commercial array designs that make the same mistake.

First of all, Rick, you need to knock it off. Those of us in the know already know that I am the only person that has designed commercially available line sources using planar magnetic drivers and low crossover points so this was obviously directed at me.

Those other recent little digs, jabs, and bashes have not gone unnoticed either. While you have been very covert in you efforts and have not mentioned me or my company by name, most still know clearly who you are referring to.

Putting everyone else down does not build you up and only makes you look bad. Please stop it.

It is very apparent that while Rick is trying to talk about the technical aspect of the OP question, the responses to his posts are fanboys who do not understand crossover design.

Jim, calling my customers a bunch of fanboys is demeaning and insulting.

Furthermore my customers know what they have, they know what they hear, and completely understand the aspects and performance of their speakers. In short, they get it.

Rick insists on insulting them but has not heard them, does not understand, and does not get it. His off topic use of this thread to insult my customers is not appreciated.

The driver C-T-C spacing of the 6" woofers is the problem and because of that the planar would have to be crossed lower. With the PT2 you really cannot go low enough to make a smooth transition over to the woofers.

This is misleading and not at all true. Center to center spacing of the woofers in a line source does not determine the crossover point and has little to no bearing on it at all.

The amount of drivers has no bearing on how low a planar should be crossed... The same acoustic principles apply to the low frequency extension for 1 or 100 woofers. Making a claim that a 6-7" woofer in a 2-way array will have 20's extension comparable to say a 10" or 12" driver is misleading and utter BS.

This is also not at all true and shows a clear lack of understanding as to what is going on with the tweeter and woofer lines.

Whether you have one driver or 100, the the low frequency or F3 point does NOT go lower.

This is also not true in application. A 5, 6, or 7 foot line of woofers used in a line source design and used in a typical listening room environment (even in a large room) will not have a response that is anything like a single woofer in the same room even if loaded and tuned the same.

Two things happen when you use a line of drivers. You get coupling and cancelling, and you get them both at the same time. It all depends on distance and wavelength. Both effect the response curve tremendously.

The Neo8 is essentially comparable to a 2" mid dome in frequency response and are best used as a mid range rather than a tweeter.

This is not really true in any since either especially the custom variant that we are using in the LS-6 and LS-9. The playing surface on the front side is only 5/8" wide and has better off axis response than even a 3/4" dome tweeter. The output also extends to 40KHz so there is no problem with it covering the range from a small woofer all the way up to 20kHz. 

The in-room measurements that have been quoted don't accurately reflect the true bass extension of the woofers.

The in room response measurement always confirms the low bass extension in that room. 

The only way to do a fair and accurate comparison is to do a nearfield test that correctly sums the output of the port and woofer.

This is not at all true for a line source. The near field measurement only tells you the output level of a single driver. Even summing in the output of the port tells you nothing about what kind of output level one can expect in the lower range once the speaker is placed into a room. This is especially true if the port is on the rear of the cabinet.

Most people know that one can push the speaker closer to the rear wall and gain more output from coupling from the port and pulling it further out into the room reduces the output levels of the port in relation to the rest of the output.

Also doubling the distance from the rear wall will cause a 6db drop in output from the reflected energy that the port will have from the rear wall. So there is no way to splice in a port response to any level that will accurately represent the port output in a room.

But those woofers won't give you the same bottom end extension that a larger driver will unless you add a massive amount of active equalization.

This is not true at all either.

It's easy to do with an active crossover but when a passive crossover is involved, physics rears it's ugly head. Since I'm not a crossover designer, here's my suggestion.

Well I am a crossover designer and the physics are the same whether the crossover is passive or active.

I'm not talking about non-linear behavior but the inherent low frequency resonances that are present in a planar driver regardless of the amount of drivers. You can see them by looking at impedance curves as well as with distortion tests. When you cross too close to / or below them you can have audible distortion and adding more drivers won't make it go away. This is true with ribbons or planar drivers.

Yes this is true, but FYI, the Fs on the custom built planar magnetics from BG average about 268Hz. Also the magnitude if the resonance is very minor and only creates a very small rise in impedance on the magnitude of a couple of tenths of an ohm. So crossing them at 850Hz or even lower and creating a third to fourth order acoustic slope is no problem at all.

nearfield tests for bass extension are widely used and accepted in the industry as being the most accurate way to determine the actual bass extension of a system.

Again, not correct at all. It will NOT determine the actual bass extension of a system. It will only determine the bass extension of a single driver in an anechoic environment.

I'll respect Fred's request and not respond here. And by the way Danny I'm using a 14'x23' room for array design - please correct the post in your circle.

[Chops]

Just an update... While people on here have been bickering on this thread (I won't name names), I went out and bought a pair of 1 month old Monitor Audio RS6 towers. I am now on a hunt for a matching center channel as well as an amp for the mains. I'm seriously considering either the Marsh Sound Design A200s or Vincent SP-331. Just have to do a little more research on both.

Anyway...

[jono2channel]

My Goodness! Those aren't what you said you were looking for in your first post.

[pbrstreetgang]

[ecramer]

might want to check this one out two

http://emotiva.com/

ED.

[Chops]

My Goodness! Those aren't what you said you were looking for in your first post.

No, but a great choice at any rate. Excellent bass, excellent midrange, excellent treble, imaging, soundstaging, etc, etc, etc... I'm happy. 

[Chops]

Not really.

[Chops]

might want to check this one out two

http://emotiva.com/

ED.

Yep, been looking at those today as well. Hmm... Choices, choices.

[jono2channel]

I looked on the Monitor website, and couldn't find what I was looking for. Are those 2.5 way?

[Chops]

I looked on the Monitor website, and couldn't find what I was looking for. Are those 2.5 way?

Yes they are. The top woofer runs all the way up to 3kHz while the lower woofer only runs up to I think 300Hz.

These little towers throw out an amazing sound and the amount and quality of deep bass will literally shock you, especailly at high volumes. I just got Tracy Thorn's latest solo album "Out of the woods", and boy can these RS6's rock! They don't seem to care how loud you play them. They just get louder and stay ultra-clean and tight. I certainly have no regrets of deciding to go with these.