The VMPS Patent, Parts I, II, III, IV

John B · « **Reply #160 on:** 21 Oct 2005, 12:34 pm »

Quote

John B, could you compare without the modifications?

Bob,

I was thinking about that very thing last night. First I want to try the recommended speaker positioning and see where we're at. Then I'll remove the modifications and see what the soundstage placement looks like. It is a very simplified means of determining what you can hear at different points in the room, and I did not bring depth of imaging into it, as in this 2-dimensional AudioCircle universe we found ourselves in

it's a bit difficult to illustrate.

Brian Cheney · « **Reply #161 on:** 21 Oct 2005, 03:20 pm »

The effect is like moving your seat in a club or smaller venue. Your visual and sonic perspective change but the balance and sound quality remain almost the same. It's quite remarkable.

The reason the sound is not quite the same is that each listening position has its own set of late arrivals from reflected energy. This is also true when changing seats in any venue. Ask concertgoers about the "best sounding seat in the house" in Carnegie Hall, Lincoln Center etc.

trekker · « **Reply #162 on:** 21 Oct 2005, 03:38 pm »

So the CD primarialy affects the horizontal dispersion and not the veritical dispersion? Is one of the benefits of the CD allow the speaker to disappear w/o having to sit in a specific spot?

Brian Cheney · « **Reply #163 on:** 21 Oct 2005, 03:40 pm »

The slot also improves vertical dispersion, as forthcoming measurements will show. The idea is to be able to sit anywhere in front or inbetween the speakers and hear basically the same sound. Goal is Constant Directivity over a 180 degree angle.

trekker · « **Reply #164 on:** 21 Oct 2005, 04:04 pm »

Sounds good to me. One reason I haven't seriouly considered VMPS for my main speakers are the comments about having a very small/narrow sweet spot. But the CD may change all that.

I do own the Original Larger Sub and it has been trouble free since I bought it mid 90's.

Arnold

John Casler · « **Reply #165 on:** 21 Oct 2005, 09:35 pm »

Quote from: ehider

Hmmm,

The measurements that I posted show the exact issues that from a speakers comb filtering due to crossover design choices. These anomolies are still present in the speaker we have been talking about and are EXTREMELY similar in terms of using the graphs I presented to EDUCATE AudioCircle readers. They are NOT there to slam VMPS or talk badly the design decisions itself. Hell, I never even offered up any opinions to what comb filtering issues mean to me personally in a speaker designer's playbook Earlier in this thread I asked Brian to respond so we could all learn from his corner. He designed the speakers afterall The WHOLE POINT of my posts are to EDUCATE everyone who is curious with VALID informative measurables, not just conjecture and speculation.

For those graphs not to be posted is a serious dis-service to anyone reading these threads that is trying to understand the relationship of comb filtering occuring due to crossover slope selection. I have to seriously wonder about this decision to block the measurements I posted. As far as I'm concerned it speaks to a complete and total lack of understanding of an attempt to just answer another poster's question where he asked ME POINT BLANK for measurements so he could understand what I was saying ...

Hi Eric,

I have to apologize for "deleting" the graphs, however I can't imagine that you feel it is "acceptable" to post measurements from a direct VMPS competitor, on the VMPS circle, as "educational material".

As you know Brian is more than happy to answer questions relating to design decisions, but it is really bad form to take competitor generated material and post it here.

You are welcome to ask questions and critique all you wish, but when you start posting inappropriate documentation, then it will be sent to another circle.

Thanks for respecting this.

Marbles · « **Reply #166 on:** 21 Oct 2005, 10:04 pm »

John,

With all due respect, BC has never posted any FR curves of any of his speakers that I'm aware of. He has mentioned he only takes them VERY CLOSE to the drivers (but does not publish them).

Maybe if BC were to post FR curves at say 1-2M from his speakers at verying spaces, say 2-4" differentials, then we could use HIS graphs.

As it is, the people who have the tools to do this right for the most part are competitors who have been dismissed as such or amatures who have been dismissed as such.

Florian · « **Reply #167 on:** 21 Oct 2005, 10:18 pm »

I think i finally start to understand this CD over 180 degrees. Sounds like my other speakers in a huge room. You can move anywhere infront of the speakers and have pretty much the same image. Also you will never hear any drivers sticking out or hear any driver by itsself. If the RM gets that too and ontop of that also gets a solid bass foundation than i think i need to upgrade my Rm30's too

Any idea when we will see the first production run?

-Flo

John Casler · « **Reply #168 on:** 21 Oct 2005, 10:34 pm »

Quote from: Marbles

John,

With all due respect, BC has never posted any FR curves of any of his speakers that I'm aware of. He has mentioned he only takes them VERY CLOSE to the drivers (but does not publish them).

Maybe if BC were to post FR curves at say 1-2M from his speakers at verying spaces, say 2-4" differentials, then we could use HIS graphs.

As it is, the people who have the tools to do this right for the most part are competitors who have been dismissed as such or amatures who have been dismissed as such.

Hi Rob,

While most know that Brian doesn't generally post measurments (although I know we posted some RM/x graphs some time back)

I think he has said that some are coming from both himself and Bascom King in the near future.

It might just be me, but I still think posting the measurements of a competitor on a "Manufacturers" Circle is bad form.

I know recently John Atkinson (Stereophile) posted some attrocious measurements of the Cyberlight cables which I have heard several times, and find among some of the best cables out there. In fact, the accomapanying Fremer review was "glowing", but the measurements basically told everyone they were "unlistenable".

Go Figure.

If you guys wish to demand numbers from Big B, have at him. Sure he has been asked before

Marbles · « **Reply #169 on:** 21 Oct 2005, 11:00 pm »

John, the point was there aren't any VMPS generated FR curves of VMPS speakers.

Anyone who posts FR curves of VMPS speakers is automatically said to either be incompetant or have an axe to grind. Ehider was asked to post "a link" to them and he posted the actual curves. Then he was blown up..and you still think it bad form.

I'm sure he would have used VMPS generated curves if they had been available.

Now it looks like you are making excuses for curves that are about to be posted. What's that all about?

tinear99 · « **Reply #170 on:** 21 Oct 2005, 11:36 pm »

Dennis Murphy posted some graphs of the RM1 on his website murphyblaster.com judge for yourself, Dennis is real good with crossovers and his measurements are spot on.

Florian · « **Reply #171 on:** 21 Oct 2005, 11:56 pm »

I think Eric posted curves from his old RM/x speakers. Why is it a bad thing to post curves? I measured my RM30's with the Tact which was quite helpfull. But it indeed difficult to get a good measurement.

-Flo

J Harris · « **Reply #172 on:** 22 Oct 2005, 01:58 am »

Hey guys

When will these be available for the 626R? I want.

Patrick (J Harris)

Brian Cheney · « **Reply #173 on:** 22 Oct 2005, 02:06 am »

No upgrades available yet. Watch this spot for details.

John B · « **Reply #174 on:** 22 Oct 2005, 02:46 am »

Part 2 of my soundstage investigation got put on hold a mite tonight. I added a couple of items to my system that had a very positive effect on the quality of my sound. This distracted me from my task

Though I did take time to remove Brian's "modifications". I got enough of that after about a minute. Talk about losing soundstage dimensionality/depth, not to mention tonal neutrality; it was not something I needed to listen to long to know that the "Constant Directivity Guides" are an integral part of the RM30's now. It's a different speaker, as you will hear when you get the upgrade or new VMPS speakers.

pugs · « **Reply #175 on:** 22 Oct 2005, 04:19 am »

Maybe it's not so simple, but can't anyone take a sheet of wood, cut a slit in it and attach it to their VMPS speakers? Would it work on any ribbon speaker?

Brian Cheney · « **Reply #176 on:** 22 Oct 2005, 04:21 am »

No, no, no. Bizarre colorations ensue. Don't do that with any speaker.

Xi-Trum · « **Reply #177 on:** 22 Oct 2005, 12:21 pm »

Quote from: pugs

Maybe it's not so simple, but can't anyone take a sheet of wood, cut a slit in it and attach it to their VMPS speakers? Would it work on any ribbon speaker?

You have to deal with the reflections. I'm guessing this is where part of the "novelty" comes in.

Tweaker · « **Reply #178 on:** 23 Oct 2005, 06:18 pm »

I've come in to this thread late so forgive me if this has already been discussed but is there plans to make a waveguide for the
RM2 with spiral ribbon tweeters? And I understand there are plans to license this to other speaker manufacturers. Will this work with moving coil loudspeakers designs?

Brian Cheney · « **Reply #179 on:** 23 Oct 2005, 07:06 pm »

The patent includes CD waveguides for cone dynamic/dome tweeter systems.

I will deal with this subject later in "The VMPS Patent--Part After the Last".