Paradigm Founder 120H loudspeaker Measurements

Sidebar 3: Measurements

I used DRA Labs' MLSSA system, a calibrated DPA 4006 microphone to measure the Paradigm Founder 120H's frequency response in the farfield, and an Earthworks QTC-40 mike for the nearfield responses; both microphones were used with an Earthworks microphone preamplifier.

I usually measure a loudspeaker's farfield behavior level with its tweeter, which the 120H's manual suggests is the optimal axis: "For the most accurate and natural timbre, place front speakers so that their high-frequency drivers are approximately at ear level." However, with the Founder 120H sitting on its outrigger stands, the tweeter is 42" from the floor, which is significantly higher than the average listener's ear height of 36". I queried RvB what axis he had used for his auditioning. He responded that Paradigm's John Bagby had told him that the acoustic center of the speaker and the measurement plane they use is between the tweeter and midrange. I therefore performed the farfield measurements on this axis, which is 39" high. I refer to this axis in the following text as the "design axis," and all the measurements were taken without the grille.

The speakers' powered woofers were still equalized with the ARC filter settings that RvB had used. I performed a set of acoustic measurements on the left-hand speaker with his settings, then installed the ARC Genesis app on my MacBook Pro and connected one of its USB ports to the port on the back of the loudspeaker. I couldn't see how to bypass RvB's ARC profile for the woofers. I therefore created a new profile with the ARC USB microphone 12" from the middle woofer. This minimized the corrective changes made by ARC and would reveal the intrinsic behavior of the woofers and the downward-firing port. I then performed another set of response measurements.

Paradigm specifies the Founder 120H's anechoic sensitivity as a high 92dB/2.83V/m. My B-weighted estimate was slightly lower, at 90dB(B)/2.83V/m (footnote 1), though this is still higher than average. The Paradigm's impedance is specified as "compatible with 8 ohms." My impedance measurement (fig.1, solid trace), taken with Dayton Audio's DATS V2 system, drops below 8 ohms in the upper midrange and top two audio octaves, with a minimum value of 3.44 ohms at 600Hz. The large increase in impedance below 300Hz will be due to the high-pass filter used to eliminate low frequencies from the midrange unit.

1122para.Para120Hfig1

Fig.1 Paradigm Founder 120H, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).

On the face of things, the Founder 120H would appear to be a relatively easy load for the partnering amplifier. However, the electrical phase angle (dotted trace) is high in a few regions and the effective resistance (EPDR, footnote 2) lies below 3 ohms over much of the audioband. The minimum EPDR is 1.5 ohms between 360Hz and 410Hz. The Founder 120H will work best with amplifiers that don't have problems driving low impedances, though the speaker's high sensitivity will reduce its need for current.

The traces in fig.1 are free from the wrinkles that would imply the presence of enclosure resonances. The enclosure did indeed seem well-damped when I rapped the panels with my knuckles; when I investigated their vibrational behavior with a plastic-tape accelerometer, what resonant modes were present were low in level (fig.2).

1122para.Para120Hfig2

Fig.2 Paradigm Founder 120H, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of sidewall level with top woofer (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).

The port's response, measured in the nearfield and with my minimized ARC setting, is shown as the red trace in fig.3. The output peaks sharply at 24Hz, which will be the port's tuning frequency, and while the upper-frequency rolloff is smooth for the first three octaves, there is a strong resonant peak at 300Hz. I could hear this peak with the noise-like MLSSA signal with the upper-frequency drivers disconnected, but it doesn't seem to have much of an effect on the nearfield output of the woofers (blue trace). The woofers roll off sharply above 300Hz, crossing over to the midrange unit (green trace) a little higher than the specified 300Hz. The 120H's upper-frequency response on the design axis has a slight peak just below 1kHz, then rises in the mid- and high-treble regions, reaching +5dB in the top octave compared with the level at 1kHz. This graph reveals that the tweeter's fundamental dome resonance occurs at 27kHz, safely above the audioband.

1122para.Para120Hfig3

Fig.3 Paradigm Founder 120H, acoustic crossover on design axis at 50", corrected for microphone response, with the nearfield responses of midrange unit (green), woofers (blue), and port (red), respectively plotted below 500Hz, 400Hz, and 550Hz.

The black trace above 400Hz in fig.4 shows the Founder 120H's quasi-anechoic farfield response averaged across a 30° horizontal window centered on the design axis and spliced at 400Hz to the complex sum of the midrange, woofer, and port responses. The shape of the trace in the midrange and treble is similar to that in fig.3, though the peak in the top audio octave is slightly lower in level. The low-frequency response has only a slight boost due to the nearfield measurement technique and rolls off very sharply below the port tuning frequency. This implies that there is a high-pass filter in the woofer feed to protect the drive units from excessive infrasonic excursions.

1122para.Para120Hfig4

Fig.4 Paradigm Founder 120H, anechoic response on design axis at 50", averaged across 30° horizontal window and corrected for microphone response, with the complex sum of the nearfield woofer and port responses without ARC correction (black) and with RvB's ARC settings (red) plotted below 400Hz.

The red trace in fig.4 shows the complex sum of the low-frequency nearfield responses with the ARC settings that RvB used to correct for his room acoustic problems. The differences between the red and black traces are minimal above 150Hz, but the red trace has two significant peaks between 50Hz and 150Hz and the low bass rolls off below 40Hz.

Fig.5 shows the Founder 120H's horizontal dispersion, normalized to the response on the design axis, which thus appears as a straight line. The off-axis behavior is well-controlled through the midrange and mid-treble, with the contour lines in this graph evenly spaced. Ridges and gullies appear to the speaker's sides in the top two audio octaves, which will be due to the peakiness in this region in the on-axis response smoothing out off-axis. The dispersion in the vertical plane is shown in fig.6. A suckout appears in the upper crossover region more than 5° above the design axis, but the response on the design axis is maintained 5° below that axis.

1122para.Para120Hfig5

Fig.5 Paradigm Founder 120H, lateral response family at 50", normalized to response on design axis, from back to front: differences in response 90–5° off axis, reference response, differences in response 5–90° off axis.

1122para.Para120Hfig6

Fig.6 Paradigm Founder 120H, vertical response family at 50", normalized to response on design axis, from back to front: differences in response 15–5° above axis, reference response, differences in response 5–10° below axis.

In the time domain, the Founder 120H's step response (fig.7) indicates that the tweeter and woofers are connected in negative acoustic polarity, the midrange unit in positive polarity. The decay of each unit's step coincides with the start of that of the next lower in frequency, which suggests optimal crossover implementation. The Paradigm's cumulative spectral-decay plot (fig.8) is commendably clean throughout the treble.

1122para.Para120Hfig7

Fig.7 Paradigm Founder 120H, step response on design axis at 50" (5ms time window, 30kHz bandwidth).

1122para.Para120Hfig8

Fig.8 Paradigm Founder 120H, cumulative spectral-decay plot on design axis at 50" (0.15ms risetime).

With the exception of that rising high-frequency response, the Paradigm Founder 120H offers excellent measured performance. I visited Paradigm's Canadian facility some years ago and was impressed by their engineering resources, which include an anechoic chamber. That exaggerated treble response must therefore be a design choice, perhaps to subjectively balance what appears from the step response to be a somewhat underdamped woofer alignment.—John Atkinson


Footnote 1: B-weighting reduces the effect of excessive energy at the frequency extremes on the calculated sensitivity. See my discussion of voltage sensitivity here and my reason for using this weighting here,

Footnote 2: EPDR is the resistive load that gives rise to the same peak dissipation in an amplifier's output devices as the loudspeaker. See "Audio Power Amplifiers for Loudspeaker Loads," JAES, Vol.42 No.9, September 1994, and stereophile.com/reference/707heavy/index.html.

COMPANY INFO
Paradigm Electronics Inc.
205 Annagem Blvd.
Mississauga, Ontario L5T 2V1
Canada
ARTICLE CONTENTS

COMMENTS
remlab's picture

Haha! So true!

RH's picture

Nice review, thanks. I was curious how these speakers would measure.
Given my experience auditioning the Persona line I wasn't surprised to see the rising top end. As JA says, seems to be a design choice.

Oh, and as a Canadian, I will affirm that meatloaf can indeed be awesome!

ok's picture

until you taste eurasian meatloafs first!

Jack L's picture

Hi

Sorry, out of audio topic...

If served with mashed baking potatoes, it can indeed be double awesome !

Being a homemade chef, I would mince really lean beef in my kitchen instead of picking up the so called "lean" minced beef from the meat stores.

Jack L

Jack L's picture

Hi

It could be double "awesome" if you would test it with bi-wiring connection already ready there !

Listening to bi-wiring is believing

Jack L

Indydan's picture

WRONG! Biwiring is useless.

Jack L's picture

Hi

Everything is "useless" to YOU "sick puppy" !

Keep on stalking, pal. You can get nowhere ! HeHee..

Jack L

Indydan's picture

Hey Jackie, you sound confused. Have a little drinky poo today?
https://preview.redd.it/v5gnqzmb6xo91.jpg?auto=webp&s=2cbfd3576b5d5254f7f3be4c8917bf7ce9514b7b

Jack L's picture

.

Long-time listener's picture

"Fig.5 shows the Founder 120H's horizontal dispersion, normalized to the response on the design axis, which thus appears as a straight line."

I would really prefer you show dispersion NOT normalized to the on-axis response (as you used to a number of years ago). To me, it presents a much clearer and more intuitive picture of actual dispersion patterns.

nunhgrader's picture

Fun review! Thank you

Kyotodoc's picture

Great review! I have the Founder 100F speakers which are the fully passive version. I have not found placement of the speakers to be an issue at all. In fact, I find these speakers to be easy to place, with great off axis response. I suspect there are some room shape/size issues that might have caused you to have to fiddle with them so much, although I am quite surprised that in a large room like yours you have them spaced only 5 1/2 feet apart. My room is much smaller and I have them 8 1/2 feet apart and 9 ft from my listening position with the speakers toed in about 18 degrees.

I agree with all your comments on the sound quality of the speakers- these are the best speakers I have ever heard or owned. They are transparent, detailed and very well balanced and coherent all through the frequency range. You didn't mention anything about their soundstage or imaging so would have liked to hear your take on that. I find the speakers do disappear and soundstage is quite tall and imaging very good. To me the closest comparable speakers are the Revel 228be but with stronger bass response and more engaging. I expect these will be my reference speakers for many years.

Jack L's picture

Hi

BINGO !

It is an acid test for quality sound system that when the music is on, the front loudspeakers should sonically 'vanished' !

Listening is believing

Jack L

Indydan's picture

If only Jackie L would vanish...

Jack L's picture

.

Jack L's picture

Hi

Really? While I have not auditionrf both the Paradigms under review & Revel 228Be side by side (Have you at all ?), I just comment on the technical specs of them.

How come Revel 228Be full-passive floorspeakers can beat the Paradigms with class-D powered woofers by "stronger bass response" ??????

Techhnically impossible !

FTI, Revel 228Be are best for large, larger room, not too good for medium & small rooms as per a publised review of a loudspeakers only review journal.

There are at least 5 brandname full-passive floorspeakers beat Revel
228Be for its deep bass response. Incidentally, they are all same: Goldear Triton series. The lower model Triton 2+ got low frequency response down to 19Hz - full passive.

Jack L

Indydan's picture

Hey Jackie L, I am blowing you a kiss.

Jack L's picture

.

Jack L's picture

Hi

"For me, it wasn't a problem: I like my music loud." qtd RvB.

Not all music should be played back "loud". Classical piano music solo performances, for instance, do not perform "loud" at all & should therefore be played back the same not so loud levels.

Any music performances,e.g rock&roll, soloist guitar or classical piano music or whatever, should be played back at their ORIGINAL performance level as heard at the attendant's location, irrespective of whoever's loudness preference.

Like the famous piano solist piece, my very favourite, Chopin Nocturne E flat major (9/2), it should be played back pretty quiet as per the title of the music : nocturne - "of night scene" in French.

With my sound level meter mounted at my ear level at my sweet spot being 11.5 ft from the front panel of each of the L & R KEF 2-way front standspeakers, set at dB(C), max level & fast reading, the whole performance hardly measured over 75dB(C). It starts with pianississimo quiet notes at around 61dB(C) & fortississimo at round 83dB(C) lasting only half a second in the whole performance.

Yet I enjoy it bigtime playing back on my CD on my cheapie non-stereophile no-name DVD player/DAC. Sooo livelike & soo spatial abundant, particularly at the piano pedal resonant decay !!! Wow.

A good sound system should just be played at the right levels, not necesssarily "loud", to retrieve the music "kick, excitement or presence".

From RvB above review per my post caption, could it be the problem of the Paradigms or the rest matching equipment ???

Listening is believing

Jack L

ChrisS's picture

...everything about yourself.

That's nice.

Jack L's picture

Hi

Why not? You "enjoy everything about" some sick dog here ??

Jack L

Indydan's picture

Aye Jack L. mon amour. Veux-tu faire du frottage fromage avec moi?

Jack L's picture

.

Indydan's picture

Aye Jackie L, je t'envois un beau bizou!

Jack L's picture

je t'ai demande d'arreter d'aboyer !

Jack L's picture

.

Jack L's picture

Hi

My second thought re yr above comment winds down to the design issue of the Paradigms: the built-in ACTIVE cross-over network.

Most most, if not all, loudspeakers with powered woofers have included a built-in active cross-over network which splits the incoming music signals from the driving amp into LF, MF & HF to drive the dedicated amps to drive the woofers, MF & HF discretely.

Without the design schematic of the Paradigms under review, I can only assume logically the built-in X-over network also handles the M/F & H/F.

It is the design issue of the Paradigms active X-over network that somewhat 'screws' up the sound at SPL below 75dB, IMO, basing on my hands-on experience in interphasing my audio system to my 3 powered subwoofers (L, R, & L+R) for soo many years.

With my design/built interphasing, I allow my subs built-in adjustible Lo-pass network to handle only the sub-LF, tapped out from the main-stream music signal driving my main front 2-way passive bi-wired KEF front standspeakers.

It means the mid-L/F, MF & HF of the music signals drive direct my front louspeakers without going thru any active electronics! It works like a chime.

I can enjoy some excellent performance playback on my 24-bit mastered gold-plated reference CD track: "The Great Gate of Kiev" from "Pictures at an Exhibition" at any any levels from solo instruments below 50 dB(C) immediately followed by some 103 dB(C) bass drum beats as per my SPL measurement. NOoo sweat !!!!

Listening is believing

Jack L

X