attitube

Well, here is the tale of putting the things together with the Rhythm kit by North Creek.

At the time that I purchased this kit from US, it was not easy to make an import from another continent into

a former communist country. George was kindly helping me by finding a freight company and dispatch the kit overseas

towards a wild country.  It was a damn adventure and a clash of nerves at the custom until I get the kit-box home!

The kit was very well packed, and the quality of all components was the best money can buy at that level of refinement.

The only thing you missed was the front covering cloth grilles!

Sporting the famous Scan Speak D2905/9900 Revelator as tweeter,

(one of the best in the world) the kit uses two 6.5″ bass drivers

SCAN-SPEAK 18W/8545SC in an 35 Liters MTM configuration with

the tweeter mounted offset.

The crossover is already build and each speaker has two separate

filters, as the project is engineered for by-amp connection. The

parts are top class:

• Crescendo precision film-and-foil capacitors
• 10 AWG low torque winding air core inductors
• Ohmite precision resistors

The Cabinet is a heavy business, very well designed, heavily braced, rigid,

dead quiet and damn tricky to build it properly. The aperiodic internal bracing

was a pain to build for a beginner like me, but my carpenter friend Mitica was

of a big help!   The front of the cabinet are consisting in a double layer

of 25 mm thick MDF, ontop of a 22 mm birch  plywood ,  resulting in a frontplate

of a 72mm !!! total thickness ( that was rigid).

The back plate of the box reaches 47mm thickness, as the sides were made from

25mm MDF. Internal bracing  was shaped, as suggested by George, in 22mm

hanmade birch plywood ( the carpenter went to a special place to make the birtch

sandwich from 3 separate layers at a special pressing machine that uses urethane,

and high pressure for veneering / multi layer wood products !) .

Finally, each of the cabinets reached  like 22Kg weight, whitout the mounted hardware.

Inside, the cabinets were religiously covered with the goop provided in the kit,

that treatment reducing further the internal resonances already reduced by the

aperiodic extensive bracing, as well as the stuffing materials ( long wire syntetic

acoustic wool). The biggest challenges for a rookie ‘carpenter’ like me was to

shape the radius for the front plates sides, and to properly cut the faceplates for

receiving the loudspekers in a flushed way.  A good idea at the time was to

create first the thick faceplate of the cabinet, then to mill the side radiuses on an industrial milling machine.

Then, after the ’rounding edges’ operation was done,  we proceed to make the flushed

holes for the speaker. In case we have a problem, we could make another faceplate

before the costly operation of making the holes. Holes are making each structure

weaker !  After the front plate was finished,  fixing this onto the cabinet in tha’ place

was another step,  precision and  tight nerves being a must. The connectors back plate

that is also a visiting plate, also needs a little attention from the beginning.  If you

forget about from the beginning , in not a disaster but that will make your life harder

later on,  as the separate crossover networks needs to be installed on the lower section

of the cabinet trough the visiting back plate, which also supports the binding posts,

and must to be attached to the cabinet in a very rigid way.

The cabinets were covered with natural pine veneer, sanded and sprayed with

transparent spray lack.

Woodworking skills, to accomplish the task of finishing this kit installation,  are crucial and I  just want to show some examples :

• Sandwiching the back wall of the Rhythm cabinet

 

 

• Internal bracing general view

• Internal bracing front detail

• Other construction montage details

• Crossover network design could be fund here, as well as few pictures of the High and Lows separate units

Some observations about the final assembly:

• be carefully and use proper tools for the spike holders on the cabinet sitting plate, as they could break under heavy torque, or  when the dedicated holes are not at the suggested diameter
• use the provided self-adezive gasket to seal the contact area of the speaker with the cabinet when installing the drivers
• be precise when marking the fixing holes for the driver units. Use a 0.5mm pencil, then a 1.5mm drill to make a pre-drill hole
• use a adjustable torque wrench for installing the drivers. make some tests before on a similar piece of material, using the same wood screw. tighten one by one the opposite screws, rising the toque with small increments. You will never get it too slow!
• take good care at the driver’s membrane while screwing around, use a mask when screwing with hard tools around the paper cones
• use the goop provided to fix the crossover networks inside the lower floor of the cabinets, as these boards must not to vibrate. can be used modern silicone for plumbing instead, with good results.
• use a weight scale to split in two all the damping wool provided, as the damoing must to be equal in both boxes
• use small magnets underside the veneer (4 of them will be enough) as this will be the most elegant clamping system for the cloth grill that protects the drivers.

Rhythm cabinet finished

Rhythm’s response 1 meter

Rhythm loudspeakers at work in  my system

The diagram, side dissection and output graph from this page were take from:

northcreekmusic

where you could find more info on these kits and their creator.

HOW ABOUT THE SOUND OF RHYTHM?

What can I say, It was the more refined speaker system I’we got so far!  Due to the use of  Revelator tweeter,

the sonic scene created by these speakers was cinemascopic large. I drove this kit with a tru class A push-pull

amps created bt Erno Borbely – the A75 – and listening to acoustic music, small jazz ensemble, choir, small scale classical

or electro music was simply thrilling.  What was amazing at Rhytm was the medium and highs: natural and coherent, with

superb voicing. The bass was more deep than you expected from such small but fierce low drivers.

The Rhythm sound is warm, sensitive and involving, very refined, still precise and focused. The sounstage is 3D

holographic, in an addictive kind of way if you have some tubes in your system! The charm of  Rhythm consists in the mix

of resolution plus extreme finesse in the middle and highs combined with the strong, big  fundament created by the bass

drivers . Whatever  the amplification used to drive the Rhythm was, the only drawback of these speakers was that trying to

listen Jimmy Hendrix or Metallica  did not transport you were expected.  Otherwise, if one plays the best recordings from his

music  library, they will sound amazing; but if  you try to enjoy some less perfect recordings, then you have a trouble – they

will sound worst than deserving 🙁

So, these kits are not for those mad about groovy blues, hard-rock  or heavy- metal music . The Rhythm presentation is too much

refined and polite for hard ‘raw’  music like “The White Stripes”,  Hendrix, “The Clash” or “System of a Down”, “Red Hot

Chilly Peppers “or “Kings of the Stone Age”  🙂

Still, they cold make you mad on Prodigy early albums! Just for the record, the ‘Amnesiac’ album of  Radiohead sounds

terrific – one of the best sound I heard in a small system ever since, with all details that creates a schizoid like atmosphere!

If you love jazz, electro, voices, small acoustic groups and generally  not complex but refined and well recorded music,

these are for you.

© attitube 2011