ProAc Tablette 10 Signature - The Good and the Ugly, incl. Crossover Schematic

0 Members and 1 Guest are viewing this topic. Read 2987 times.

Jila

Specifications from ProAc website:
Nominal Impedance: 10 ohms
Recommended Amplifiers: 5 to 50 watts
Frequency Response: 55Hz - 30kHz
Sensitivity: 86 dB linear for 1 watt at 1 meter
Bass/Midrange: ProAc 5 inch with Paganni Mika cone, with acoustic coating and copper excel magnet system with solid copper phase plug.
Tweeter:  1 inch (25mm) ProAc silk dome air cooled and inner damping.
Crossover: “Finest components on dedicated circuit board. Multistrand oxygen free copper cable throughout. Split for optional Bi Wiring or Bi Amplification”.
Dimensions: Height: 12" (305mm), Width: 7" 1/2 (191mm), Depth: 6" 1/4 (159mm)

I wrote this blog to provide some in-depth look at the design approach ProAc took with the new Tablette 10 signature monitor speaker. It proudly wears the signature of the ProAc Founder, Managing Director and design authority Stewart Tyler, who sadly passed at the beginning of July this year. The impressiveness of ProAc’s speakers, incorporating his designs, work, and influence will not be forgotten.





First impressions:
Listening to the ProAc Tablette 10 Signature through my modified Audion Edison 60+ tube amplifier with 2x2 Electro Harmonix EL34 in parallel singled ended mode, a Chord 2Cute DAC and Tidal Master music files, the tonal balance and accuracy of the original timbres is striking. My listening room is relatively small with some acoustic treatment and thus the home turf for a small monitor speaker without port. The ProAc Tablette 10 Signature easily plays its part. Critical Listening reveals the speakers space and openness, almost analytical, with a high emphasis on detail, achieved through a boosting of the high frequencies. Despite the small and closed cabinet, sensitivity, i.e. the amount of sound output (Sound Pressure Level , SPL) measured in decibels (dB) is still reasonable.

The Anatomy:
A thin walled heavily damped infinite baffle enclosure, with bitumen inner cladding and a few layers of anti-resonance foam results in a cabinet that behaves more solidly than heavier built boxes.
Speakers:
A new bass/middle driver, purpose built for ProAc by Norwegian speaker manufacturer SEAS, made of a Paginna Mika cone material with a high-quality copper magnet system and phase plug. The tweeter is ProAc’s highly renowned 1″ silk dome model which is also used in many other ProAc models.

Crossover:
ProAc claims: “Finest components on dedicated circuit board. Many months of measuring and listening were taken”. Really? Granted, three capacitors are probably good quality Poly Caps, although not easily identifiable due to covering by ProAc labels. None of the inductors are air core, have ferrite cores that are not even laminated ferrite. The LCR notch filter inductor is of ‘dental floss’ gauge, and includes, wait for it, an electrolytic capacitor! This is perhaps in the notion that a notch filter is not in the signal path. Everything in a crossover is in the signal pass! These are cheap budget parts that don’t belong in a US$1,900.00 to US$2,220.00! What were they thinking?

Schematic picture:



Tracing the circuit diagram from the board that is mounted with ferromagnetic (!???!) hardware to the rear panel. I have not yet measured the values of inductors and capacitors. At least the notch filter helps to eliminate the traditional ProAc 2kHz bump in the frequency response.





Crossover Transfer Function picture attached, all measured at very close range with REW and miniDSP UMIK-1 calibrated USB measurement mic. Crossing a small bass-mid driver to a tweeter is obviously just a single crossover point, one that can be high up in frequency, given ProAc’s good bass-mid driver at circa 5kHz, resulting in a seamless and coherent transition. The bass/mid drivers decay characteristic looks good, with some energy propagating beyond the 300ms range, but probably below audible levels.



In summary: the ProAc Tablette 10 Signature is an excellent speaker. However, the performance could easily be raised to the next level with crossover parts that cost a few dollars rather than cents, although I realise speakers are designed to a budget, but this is not a cheap purchase. In doing so, the improvements would be audible as better:
•   Layering – The reproduction of depth and receding distance, which audibly places the rows of performers one behind the other.
•   Low-Level Detail – Subtle elements of sound, incl. the fine details of instrumental sounds & the final tail of reverberation decay.
•   Openness – a good width and depth in the presentation of sound. Plenty of room between the instrumentation.
•   Resolution - Microdetails in sound. The "texture" of the sound.
•   Soundstage – A 3D sound space, a wide soundstage allows to discern different positions for various sounds.