[KevinW]

I heard Soundguy3's RM40's last night, and was mightily impressed.  These have the TRTs, FST's, and Analysis Plus cable upgrade.  I couldn't help but wonder a couple of things...  What are the XO points in the speaker, and are the XO's first order, or fourth, or something else?

[Brian Cheney]

Crossovers are at 166Hz and 7 kHz, and are series first order networks with all drivers in phase electrically and acoustically.

[KevinW]

Cool...  I really like the idea of no XO in the midrange.  The results speak for themselves.  Any reason why you chose a series XO vs. a 1st order parallel XO?

[Brian Cheney]

The series filter transits from 6dB to 12dB characteristics with only two parts.  And it's phase coherent like the first order network.  Elegant and simple, with very little loss or compression.  Bud Fried and I have always been fond of the QSO (quasi second order, or series first order) filter.

[ekovalsky]

Brian,

How about a two piece per side system (a la Genesis), with a woofer column and a mid/tweeter column per channel?

I've recently been experimenting with placement of the RM40's.  The soundstaging and midrange/treble clarity were dramatically better when the speakers were placed far out into the room.  I tried this after reading the article on the Cardas website and used their formula, centering the woofers 0.267 x room width (48") from the side walls and 0.447 x room width (76") from the front wall.  Listening position made an equilateral triangle with the two speakers, and the speakers were toed in enough so I was listening about 10 degrees off axis from each.

The bass was a lot better when I followed the VMPS recommendations, i.e. further separation of the speakers, about 16" space between the speaker cabinets and the front wall, and lots of toe with a "crossfire" arrangement.  

I guess the best of both worlds requires four big cabinets.

[John Casler]

Brian,

How about a two piece per side system (a la Genesis), with a woofer column and a mid/tweeter column per channel?

I've recently been experimenting with placement of the RM40's.  The soundstaging and midrange/treble clarity were dramatically better when the speakers were placed far out into the room.  I tried this after reading the article on the Cardas website and used their formula, centering the woofers 0.267 x room width (48") from the side walls and 0.447 x room width (76") from the front wa ...

Being a "soundstage/imaging" nut, I have long extolled the virtues of "middle of the room" listening.

And in using this set up I have generally found that bass is a casualty.

As an experiment, I used the Bass sections of my Tower IIs (twin active 12" and 12PR) to supplement my RM40s.

It is rather devastating in the bass dept.  Even with the RM40 woofs switched off (toggle up and wired in bottom posts only) the bass is rather prodigious.

A couple times when I saw Old Tower IIs and such I mentioned that they may make good bass modules, by simply flipping the toggle and powering the woof section.  Only problem is the x-overs probably won't match perfectly, but a little placement could go a long way toward helping that.

Kind of a fun thing to do.  And the older Towers can be had for a "song" on E-bay.  If I remember correctly the LARGER SUB is nothing more than the woofer section of the Super Tower of years gone by. (as if that were not enough )

Uh OH!! UPS just arrived with the "Super Tweak" materials.

Will report soon.

PS, the VMPS Reference Cuts Volume One Disc One has finally been completed.  (including a couple of Brian's favorites) I'll post about it soon also.  Disc Two will be an all Classical Collection of Reference Cuts.  As Always I'm waiting for stuff to arrive to burn onto it.

Volume One is Pop stuff and it is Dyno-mite

[Tyson]

John,
Any cuts on the classical cd I might recognize

[John Casler]

John,
Any cuts on the classical cd I might recognize

Hey Tyson,

Well the Classical is still "in development and production", but I bet some of your suggestions make the cut.  They are ordered but havent arrived yet.

I'm putting them together for my clients to help them set up their speakers for the best soundstaging and imaging.

I still have to write the synopsis on each cut and how it is "supposed" to sound when properly set up.

It's a lot of freakin work. (searching, auditioning, deciding, burning, copying, analyzing, writing, packaging and shipping)    

Whew getting tired just thinking about it and this is only Disc ONE  

I'll be sending them to my clients as part of being a dealer (I'll send you one too), but I might offer them to others if they want them.   They include a detailed "set up" system that works with all speakers and systems.

Oh and I am almost ready to release the SUPER RM40 Tweak.  It is currently seeming to be the best $49 any one with RM40s could spend.

It is a Top hat and Lapels for the RM40s    (nope not yet)

[KevinW]

Oh and I am almost ready to release the SUPER RM40 Tweak. It is currently seeming to be the best $49 any one with RM40s could spend.
It is a Top hat and Lapels for the RM40s   (nope not yet)

Aha, I think that confirms my theory on what this super secret tweak actually is.  Am I right John?  

If anyone else wants to figure out what John is probably doing, check out this thread on Edge Diffraction on the GR forum, and scroll down to my post(s):  
http://www.audiocircle.com/index.php?topic=1101&postdays=0&postorder=asc&start=10

Assuming my guess is right, I think John has a very good idea, and his product will be well worth the money to achieve a significant upgrade in sound quality.  In fact, the speakers I am developing have exactly the same idea already built in.

[Sedona Sky Sound]

Hello John,
  You do realize that copying music material (in whole or part) without express written concent of the copyright owner is ILLEGAL don't you  ? That's the reason I currently do not have music on my set-up CD-ROM except for test tones I personally created (at least until I get my friend who owns the recording studio to generate some tracts copyrighted to me   ). Therefore, I assume when you say "burning, copying" you actually mean "recording myself playing the guitar, and copying it to CD"   .  

I also can't wait to see your Super-Tweak. Happy listening.  

Julian
www.sedonaskysound.com

[John Casler]

Hi Julian,

Of course all my cuts are made from "non-copywrited" material

I'm sure you also know that using ASCAP and BMI registered music for an "audition" to sell speakers without paying the ASCAP/BMI fees is also illegal

I'm surprised the "ASCAP" police haven't been busy busting at "Audio Conventions", like they do Restaurants and Aerobics Studios.

I hope this SUPER TWEAK isn't a "BUST" but I will say it certainly "sounds" incredible at this point.  To my way of thinking it gives the RM40s a more similar character to the RM/x, by reducing the refractive surface of the cabinet (hint, hint)

In fact, to this point, it is the single most result producing tweak I have performed on my system.   SInce I listen nearfield, it doesn't seem to add any lobing, additional beaming, or frequency "suck outs" so, I'll be taking some pictures soon.

[wshuff]

Hey John,

Count me as a client who would like a copy of "your" CD.

Also, did you previously say that your UberTweak is something that would also work on a 626R?  If so, by all means let me know.

Gracias.

[BrunoB]

Crossovers are at 166Hz and 7 kHz, and are series first order networks with all drivers in phase electrically and acoustically.

I looked at the schematics of the crossover of my 626R and I can see the series crossover between the woofer and the mid panel. But for the tweeter, I have the impression it is connected in  parallel to the two other drivers like in a second order network (one cap + one inductor). Is the tweeter also in a series first order network for the 626R? I don't know much about crossovers but I am curious about the speakers I own (and built as a kit).

Bruno

[Brian Cheney]

The woofer and mid are in series.  The tweeter is added at 7kHz at 6dB oct.  An additional filter pole out of band (around 4 KHz) accelerates the rolloff below that frequency.

[lkosova]

Geez Julian,

It's amazing how much John sounds like Diana Krall when he sings!!!

Larry

[BrunoB]

The woofer and mid are in series.  The tweeter is added at 7kHz at 6dB oct.  An additional filter pole out of band (around 4 KHz) accelerates the rolloff below that frequency.

Do the speakers with the biwiring/biamping option have a series crossover?


Bruno

[Ric Schultz]

Brian,
While the 626R is clearly a series crossover (one inductor and one cap used for both the mid and woof), I don't see this in my RM-40 kits.  You have a separate inductor for the woofs running from their own binding posts and a different value inductor with cap before it on the midrange coming directly from the midrange/tweeter posts.  The woof and midrange are not tied together.  It looks like (from the schematic) that you used do do a series xover when there was only one binding post or when you used two binding posts you could biwire/biamp for the tweeter only........can you explain further?....thanks.  I would assume everyone is now getting their RM-1s, RM-2s, RM-30s, RM-40s with two sets of binding posts and no switches.  If so, then I would think the only speaker that has a series crossover is the 626R......No?!?

[Brian Cheney]

Series crossovers are standard on the 626 and LRC and the cone dynamic systems.  RM2 and up are parallel crossovers and biampable.  If you don't plan to biamp or biwire a series filter configuration is available on the RM 2,30, and 40.

[BrunoB]

The woofer and mid are in series.  The tweeter is added at 7kHz at 6dB oct.  An additional filter pole out of band (around 4 KHz) accelerates the rolloff below that frequency.

Wouldn't it be beneficial to have a  three way series crossover?
(I just found this   interesting reading about series crossovers)



I can see a disavantage for a three way system: in a cascade series network,  the high frequency current has to go through two sets of caps to reach the tweeter. This network would need very transparent caps.

Bruno