the crescendo (grande) speaker system - diy hifi … manual 0.9.pdfdiyhifisupply® the crescendo...

diyhifisupply®

The Crescendo (Grande) Speaker System

diyhifisupply®


Table of Contents1 INTRODUCTION AND OVERVIEW 2 CRESCENDO DRIVER SPECIFICATIONS 2.1 CRESCENDO LF DRIVER 2.2 CRESCENDO HF DRIVER SPECIFICATIONS 2.3 DYNAFONE SUBBASS DRIVER SPECIFICATIONS 3 CRESCENDO ENCLOSURE DESIGNS 3.1 CRESCENDO 2 WAY 3.2 CRESCENDO SUBWOOFER 4 CRESCENDO CROSSOVER AND CONNECTIONS 4.1 CRESCENDO 2 WAY CROSSOVER 4.2 CRESCENDO SUBWOOFER CONNECTIONS 5 CRESCENDO ASSEMBLY PICTORIAL 6 CRESCENDO CONNECTIONS AND SETUP 6.1 CRESCENDO SETUP 6.2 CRESCENDO CONNECTIONS 7 TECHNICAL DATA

diyhifisupply®


1 Introduction and Overview

High Efficiency, friendly size, reasonable bandwidth and good sound. SET friendly. Impossible dream?

Unfortunately horns with any bandwidth are the size of a refrigerator. So…we have developed a horn ribbon based system which achieves our goals. The wide band horn ribbon covers from about 600hz to 23khz. The special carbon fiber reinforced paper cone cast frame 8” Driver covers below that, using 1st order (phase-coherent) crossovers.

The 600Hz Crossovers uses extreme quality parts: all film caps, oil paper and copper foil inductors, Silver Wire, Kiwame Resistors etc.

The Systems sensitivity is an honest 98db/w (100db in room as specified by many speaker manufacturers), nomi-nally 8 ohms. The box is 30L and covers from about 60hz to 23khz in room. The Crescendo can be used with many commercial Subwoofers to extend the low frequency response.

The -6dB coverage angle for the Crescendo HF 50 degrees horizontal and 30 degrees vertical. Such controlled dispersion over such a wide frequency range ensures that even in acoustically difficult rooms and the midrange and treble remain from excessive reflections and room reverb.

There is an option for bass modules – making the Crescendo into the the Crescendo Grande System. We wanted a cabinet that could slip under the Crescendos and take the place of the stand. For this a really beefy, quick bass driver was needed, which happens to be exactly what the DynaFone is. The cabinet is about 50L and tuned to cover down to 25hz flat.

Also needed was lots of power to drive the bass modules. We use some high quality plate Amplifiers which give us about 250w in a

small footprint integrated into the woofer cabinet. This bass system has no problem keeping up with the Cres-cendo horn ribbons while at the same time giving up really clean earthquake tones in our 170m2 shop.

How does it sound? The dynamics from this combo are pretty scary at times. Since the ribbon is horn loaded, wideband and closed on the back (doesn’t need nor use the box) it gives Electrostatic levels of trans-parency and immediacy, and the coherence of a full-range driver.

diyhifisupply®


2 Crescendo Driver Specifications

2.1 Crescendo LF Driver

Diameter: 8"(210mm) to basket rim edge. Cone Material: Aluminium AlloyImpedance: 6OhmPower Handling: 50W continous

100W programmeXmax: 3mm peak-peak Re: 5.2 OhmMoving Mass: 19.5 grammFs: 90HzQts: 0.45Spl (2.83V/1m): 98db

Rec. Enclosure: 30 Liter Net Volume70 Hz Port Tuning(110cm2 port crossection, 13cm port length)

* Frequency AND Impedance Response in recommended enclosure

diyhifisupply®


2.2 Crescendo HF Driver Specifications

Dimensions: 220mm X 275mm Waveguide Material: Aluminium AlloyDiaphragm Material: Kapton

Ribbon Surface: 91cm2

Fs: 480HzImpedance: 6OhmPower Handling: 60W continous

120W programmeSpl (2.83V/1m): 102db

diyhifisupply®


2.3 DynaFone Subbass Driver Specifications

Diameter: 10"(260mm) to basket rim edge. Cone Material: Aluminium AlloyImpedance: 8 OhmPower Handling: 200W continous

400W programmeXmax: 14mm peak-peak Re: 7.6 OhmMoving Mass: 75 grammFs: 35HzQts: 0.34Spl (2.83V/1m): 87.5db

Rec. Enclosure: 33 Liter Net Volume26 Hz Port Tuning(110cm2 port crossection, 95cm port length)

* Frequency AND Impedance Response in recommended enclosure

diyhifisupply®


3 Crescendo Enclosure Designs

3.1 Crescendo 2 Way

The Enclosure for the Crescendo System can be arranged quite wide arrangements as long as the volume and tuning is preserved.

Here the design we use and recommend. It uses a simple box with a large cross-section port, to avoid compression and port noise.

The material should be void-free plywood, 18mm thick. Of course, Corian or Natural stone or solid stave-glued hardwood, or bamboo may also be used.

Glue with good filling properties is recommended for any of the wood materials, Grip-Fill (the professional version of liquid nails) or similar work well, as can resin based glues. Stone requires special glues.

The Back Panel is kept removable to allow the low frequency drivers to be mounted from behind. Unless you wish to use an external enclosure for your crossover building it on the removable back panel allows easy access for modification.

We suggest to first try the box without any stuffing or damping material. All the resonance modes caused by the enclosure dimensions are high enough in frequency to not appear within the operating bandwidth of the low frequency driver, mainly due to the low crossover point.

diyhifisupply®


3.2 Crescendo SubwooferThe Crescendo Subwoofer uses an enclosure that is a “cross” between a traditional vented box and a transmission line, called a mass-loaded transmission line.

The enclosure material comes down to similar choices as the Crescendo 2-way speaker. Make sure all seams etc. are well sealed.

Again, you can choose other mechanical arrangements as long as you keep the volume and port cross-section as well as port length.

The Plate Amplifier is mounted into the side of the enclosure in a suitable cutout.

The Amplifier includes the necessary sealing strips, to make sure the mounting is air-tight and the correct mounting screws.

The Dynafone driver is directly connected to the output leads fitted to the Amplifier.

diyhifisupply®


4 Crescendo Crossover and connections

4.1 Crescendo 2 Way CrossoverThe Crossover is as shown below. One possible way to assemble this crossover is shown on the right hand side.

diyhifisupply®


4.2 Crescendo Subwoofer connections

The Amplifier build into the Crescendo subwoofer is required to boost the signal a good deal (around 14dB or five times the voltage, or 25 times the power) to to allow the subwoofer to match the Crescendo 2 Way.

We generally do not recommend to use line-level feeds or active crossovers, instead simply connect the speaker level feed via an adapter cable as shown to the RCA Input (L or R does not matter).

The final crossover and level settings for the Subwoofer depend at least to a degree on room size and personal preference. As a starting point, set as shown below:

diyhifisupply®


5 Crescendo Assembly Pictorial

diyhifisupply®


diyhifisupply®


6 Crescendo connections and setup

6.1 Crescendo SetupThe system produces large amounts of SPL and very high levels of low frequency sounds. Placing the speaker rigidly coupled to the floor not only aids the sound quality, but is essentially to keep the speakers from “wandering about”. We recommend spikes or cones. Equally, it is essential to create an interface between

Subwoofer and 2-Way that is rigid or at least prevents 2-Ways from moving (e.g. small patches of blue-tack).

6.2 Crescendo ConnectionsAs designed the Crescendo 2-Way has binding pots for bi-wiring. If you do not use Bi-Wiring speaker cables you need to link both the negative and positive binding posts.

diyhifisupply®


You also need to connect the inputs of the subwoofer amplifier, as shown in the example below.

diyhifisupply®


7 Technical DataWoofer: One – 10 inch (26 cm) Aluminum ConeWoofer Amp: One – 250W Amplifier with electronic

crossoverMidrange: One – 8 inch (21 cm) Carbon Fiber / PaperTweeter: One – 14in2 (91cm2) magnetic planar driverSensitivity: 98 dB @ 2.83V @ one meter @ 1 kHzImpedance: 8 ohms, 5 ohms minimum @ 300 HzFrequency Resp.: +/-3 dB 26 Hz - 20kHz Min. rec. power: 2 watts per channelOverall Dimensions:Height – 110 cm w/o spikes

Width – 25.6 cmDepth – 35.6 cm

the crescendo (grande) speaker system - diy hifi … manual 0.9.pdfdiyhifisupply® the crescendo...

Documents