Philharmonic Audio

The Philharmonic 3

The flagship Philharmonic 3 provides the deepest bass response of all our speakers.  The state-of-the-art ScanSpeak Revelator 8-inch woofer extends useful bass response down to 20 Hz with very high power handling across the entire bass spectrum.  For two-channel music applications, there should be no need for a separate subwoofer to enjoy the full impact of a symphony orchestra.  For increased realism, the BG Neo8 planar midrange driver is housed in an open-back midrange chamber that adds ambiance and depth to the sound stage.  The amount of back wave information may be tuned to suit the needs and tastes of the user by varying the amount of acoustic fill in the cabinet chamber.  Highs are handled by the superb RAAL 10D ribbon tweeter.  Sorbothane feet isolate the upper midrange-tweeter cabinet from bass vibrations. 

The carefully optimized 19-element crossover achieves nearly perfect 4th order acoustic slopes and remarkably flat frequency response and impedance across the audio spectrum.  Capacitors are Clarity Cap polypropylene except for the woofer-circuit capacitor, which is a Solen Fast Cap polypropylene.  Resistors are Mundorf noninductive.  All inductors are air core except for the woofer circuit, where the transmission line tuning requires the very low resistance provided by steel laminate inductors.  Although we do not encourage upgrades in the standard crossover components, purchasers may specify premium capacitors or resistors for the difference in our acquisition cost. 

Cabinets for the Philharmonic 3 are made to order domestically with the customer’s choice of veneer.  Pricing for the Philharmonic 3 starts at $3,500 a pair in standard veneers such as cherry or maple.  More expensive veneers are available at additional cost.  A slightly revised cabinet with a sloped front baffle and 1.25" chamfered edges is available for $3,700/pr.

The custom Phil 3's shown above, in walnut burl and pepperwood, were ordered by a Grammy-award-winning recording engineer for use as his reference monitors. 
The custom Phil3 shown below is in pau ferro rosewood.


Drivers ScanSpeak 22W8851T00 “Revelator” 8-inch woofer, BG Neo8 planar midrange, RAAL 70-10D ribbon tweeter
Response 25Hz – 20kHz (+/- 2 dB)
Sensitivity 85 dB (db/2.83v/1M)
Box Alignment Mass-loaded transmission line
Dimensions 43" H x 12" W x 24" D

Frequency Response and Impedance Measurements

The Philharmonic 3 has been designed to deliver as even a frequency response into the room as possible.  The sound you hear is determined both by the on-axis response, which is the first arrival of sound to your ears, and by subsequent delayed arrivals from reflected sound.  In order to provide a smooth and focused sound field across the sound stage, the combined on-axis and off-axis response of the speaker should form a flat “power response.”  As the following frequency response measurements illustrate, the Philharmonic 3 demonstrates exceptionally flat response both on axis and off axis.  This is due to careful crossover design, the very broad horizontal dispersion of the RAAL tweeter, and the shape of the upper cabinet module, which minimizes diffraction effects. 

If you study the on-axis response carefully, you will see that it is slightly depressed in the region between 1500 Hz and 2500 Hz.  This contouring compensates for a small increase in the output in this region beginning at 45 degrees off axis.  The various curves sum to produce a virtually flat overall response that is free of the peaks and dips that characterize most speaker systems.

The following measurements are “anechoic” and are restricted to the region above 200 Hz.  The test signal that produces these plots is very short, and the subsequent measurements are free of the thousands of reflections that would otherwise produce a jumble of peaks and cancellations from these reflections.  The plots thus measure the inherent response of the speaker system.  Because the measurement “window” is so short, it is impossible to capture the longer sound waves of frequencies below about 200 Hz.  The following section, “Woofer Enclosure Design and Performance,” addresses the predicted response of the Philharmonic 3 below 200 Hz.

On-Axis Response

15 Degrees Off Axis

20 Degrees Off Axis

30 Degrees Off Axis

45 Degrees Off Axis

The following plot shows the “reverse null” of the Philharmonic 3, which uses a “Linkwitz-Riley 4th Order” crossover.  For this type of crossover, the drivers should be precisely in phase with each other where they overlap at the relevant crossover frequency.  If this goal has been achieved, then reversing the connections to the midrange driver will throw it fully out of phase with the woofer and tweeter, and a deep null should develop at the crossover frequencies as the output between the woofer and the midrange, and the midrange and the tweeter cancel.  As the plot demonstrates, this in fact occurs at the crossover frequencies of about 640 Hz and 2800 Hz.

Reverse Null

The last plot presents the impedance measurement for the Philharmonic 3.  Impedance is practically flat above the Transmission Line tuning region and should present no problems to any amplifier capable of stable output into a 4 ohm load.

Complex Impedance


Woofer Enclosure Design and Performance

The Philharmonic 3 utilizes a ScanSpeak 22W8851T00 “Revelator” 8-inch woofer in a mass-loaded transmission line (ML-TL).  The line length is 66 inches, with a net volume of almost 80 liters.  A rectangular mass-loading port is located near the end of the line, exiting through the top of the woofer enclosure at the rear.  For a better understanding of an ML-TL, see “What’s an ML-TL?”.

Based on a 2.83-volt input, the following modeling graphs show the expected performance of this woofer in its TL.

System bass response (red line):

Due to this woofer’s high performance, F3 models at 27 Hz, F6 at 22 Hz and F10 at just below 20 Hz.  These are anechoic projections, and do not take into account room gain, which will significantly increase bass output.

Woofer (red line) and port (blue line) responses:
Impedance characteristic (red line):
Woofer excursion (red line):
Port air velocity as a percentage of the speed of sound:

With this input of 2.83 volts, the port’s air velocity peaks at 0.8% of the speed of sound, or 2.7 m/s.

Increasing the input to 40 watts into this nominal 8-ohm load:

System output (red line):

This 40-watt input causes the system to generate ~105 dB SPL from 30 Hz on up.

Woofer excursion (red line):

The ScanSpeak woofer has a rated Xmax of 9 mm Peak.  Allowing an additional 15% excursion increases that to 10.4 mm Peak, and converting that to mm RMS gives a value of 7.3 mm, which is shown in the above graph as being reached at both 34 Hz and just before 20 Hz, then exceeding that below.

Port air velocity percentage:

The port’s air velocity reaches its peak of ~4.3% of the speed of sound (14.7 m/s) at 23 Hz.