Genius SP-HF3000A (discontinued) powered PC loudspeaker measurements

[dominikz]

This is a quasi-anechoic spinorama measurement + internal amp measurements of the Genius SP-HF3000A (discontinued) powered PC/multimedia loudspeaker.
It is quite an old product and there's not a lot of data available about it online anymore - here's one link with some very basic information. 10 or so years ago it was one of the cheapest 5" two-way active loudspeaker pairs one could buy where I live (I believe price was ~50-60€/pair).

Loudspeaker measurements

A few notes on measurement methodology:

• The loudspeaker has been measured at ~120cm distance from any reflective surfaces, with the microphone at 1m distance from the speaker, so the first reflection was around 4,6ms after the main impulse.
  • I typically try to measure at 50cm to maximize the gate length, but with this loudspeaker there was a change in on-axis response when I moved a bit further away (perhaps due to large distance [14,5cm] between woofer and tweeter), which is why I settled for 1m. The shorter gate further reduces mid-frequency resolution, sadly.
    
    
• The reflections were removed by temporal gating at ~4,6ms in REW to get some (low) resolution of quasi-anechoic measurement down to about 500Hz range (resolution is much better above ~2kHz).
• LF response (<500Hz) is spliced from nearfield measurements (baffle step corrected) and therefore not absolutely accurate. Take the absolute shape of the response there with a few grains of salt.
• The loudspeaker front baffle was vertically aligned with the centre of speaker stand/turntable rotation
• Loudspeaker stand has been covered with a blanket to reduce potential reflections and care was taken to angle the microphone boom to minimize boom reflections
• Microphone was pointed at tweeter axis
• REW, Cross-Spectrum labs calibrated Dayton EMM-6 microphone and RME Babyface interface was used to measure, and VituixCAD to generate the spin (exported with 1/24 octave resolution)
• Measured without loudspeaker grille

Basic measurements
Here's the full spinorama for the powered (right) loudspeaker:

Preference rating as calculated by VituixCAD is:

• Speaker alone: 2.2
• Speaker with sub: 5.2

We have very uneven response (especially on-axis) and a large directivity error between 1,6kHz-7kHz. Interestingly, the response around 60-70 degree off-axis approaches some semblance of flatness:

Perhaps it was designed to be listened without any toe-in? Hard to say, but the overall objective performance is not good.

Driver nearfield components:

We can see a couple things here:

• Very prominent resonances in the port NF measurement - using the VituixCAD 'Box volume' calculator indicates these are probably undamped box height resonances
  [EDIT 2021-11-28] Effect of damping material on box resonances has been explored in post #10.
• There is no real crossover - woofer is running full range and breaks up. If you open the speaker you see that just the tweeter is "high-passed" with a simple electrolytic cap

Horizontal directivity to 90 degrees:

Horizontal directivity (normalized to on-axis response):

Impedance
Here's the impedance for both units in the pair:

As we can see, there are several visible resonances in the responses.

Distortion
76 dB SPL

86 dB SPL

Bass distortion became pretty audible around 80dB SPL and I was scared to go over 86 dB SPL.

Amplifier measurements
I disassembled the powered loudspeaker and did a few basic measurements of the built-in amplifier directly with an 8,2 Ohm power resistor.
The amplifier is based on 2 pairs of bridged TDA2030A class A/B chip amps mounted to a relatively small aluminium heatsink.

There is even a schematic of the amplifier circuit available on-line, so I drew the circuit in VituixCAD to simulate the amplifier. After measurement I compared the simulated response with the measured ones (in both cases with tone controls set to neutral / mid-point):

As we can see there is an aggressive low-cut (probably to protect the woofer) and we can also see a ~4dB high-shelf. This can be somewhat mitigated by reducing the Treble tone control by ~10-20% to be within ~1dB of the LF, but a perfectly flat frequency response cannot be achieved, e.g.:

Or:

Here's what the tone controls do at their extremes (responses normalized to mid-position response):

Amplifier response at 5W into 8,2 Ohm load:

Let's now look at HD vs input level into 8,2 Ohm power resistor with amp volume set to max:

With both channels 1% THD is reached with ~750mV input which results in 14,3V output - so power into 8,2 Ohm at 1% THD is around 28W. So perhaps the 40W per channel rating at 10% might be possible (though I think heat dissipation from the small heatsink would be very problematic at those levels).

Distortion spectrum at 5W into 8,2 Ohms:

Conclusion
Looking at the data, objectively this is not a very impressive pair of speakers. However, considering the low price (and lack of alternatives at the time) these were IMO not too bad as PC/multimedia speakers. We even used them for TV sound for a while, before buying a nicer pair - they were definitely much better for this than the built-in TV speaker. Going forward I plan to use them as a DIY project to learn more about loudspeaker design.

In case @MZKM, @pierre, @Maiky76 (or others) might be interested to do their magic, CTA-2034-A exports from VCAD are attached as well.

[EDIT 2021-11-28] In-room measurements and some listening impressions with corrective EQs added to post #9.

 

[sweetchaos]

Thanks for your efforts. Contributing to the pool of measurements…love it.

 

[McFly]

Nice work, well done. Shame about the speaker. Would probably give some people headaches.

 

[dasdoing]

Roland Ma-12c would be intresting

 

[Maiky76]

This is a quasi-anechoic spinorama measurement + internal amp measurements of the Genius SP-HF3000A (discontinued) powered PC/multimedia loudspeaker.
It is quite an old product and there's not a lot of data available about it online anymore - here's one link with some very basic information. 10 or so years ago it was one of the cheapest 5" two-way active loudspeaker pairs one could buy where I live (I believe price was ~50-60€/pair).

Loudspeaker measurements

A few notes on measurement methodology:

• The loudspeaker has been measured at ~120cm distance from any reflective surfaces, with the microphone at 1m distance from the speaker, so the first reflection was around 4,6ms after the main impulse.
  • I typically try to measure at 50cm to maximize the gate length, but with this loudspeaker there was a change in on-axis response when I moved a bit further away (perhaps due to large distance [14,5cm] between woofer and tweeter), which is why I settled for 1m. The shorter gate further reduces mid-frequency resolution, sadly.
    View attachment 167221
• The reflections were removed by temporal gating at ~4,6ms in REW to get some (low) resolution of quasi-anechoic measurement down to about 500Hz range (resolution is much better above ~2kHz).
• LF response (<500Hz) is spliced from nearfield measurements (baffle step corrected) and therefore not absolutely accurate. Take the absolute shape of the response there with a few grains of salt.
• The loudspeaker front baffle was vertically aligned with the centre of speaker stand/turntable rotation
• Loudspeaker stand has been covered with a blanket to reduce potential reflections and care was taken to angle the microphone boom to minimize boom reflections
• Microphone was pointed at tweeter axis
• REW, Cross-Spectrum labs calibrated Dayton EMM-6 microphone and RME Babyface interface was used to measure, and VituixCAD to generate the spin (exported with 1/24 octave resolution)
• Measured without loudspeaker grille

Basic measurements
Here's the full spinorama for the powered (right) loudspeaker:
View attachment 167207
Preference rating as calculated by VituixCAD is:

• Speaker alone: 2.2
• Speaker with sub: 5.2

We have very uneven response (especially on-axis) and a large directivity error between 1,6kHz-7kHz. Interestingly, the response around 60-70 degree off-axis approaches some semblance of flatness:
View attachment 167208
Perhaps it was designed to be listened without any toe-in? Hard to say, but the overall objective performance is not good.

Driver nearfield components:
View attachment 167209
We can see a couple things here:

• Very prominent resonances in the port NF measurement - using the VituixCAD 'Box volume' calculator indicates these are probably undamped box height resonances
• There is no real crossover - woofer is running full range and breaks up. If you open the speaker you see that just the tweeter is "high-passed" with a simple electrolytic cap

Horizontal directivity to 90 degrees:
View attachment 167210

Horizontal directivity (normalized to on-axis response):
View attachment 167212
View attachment 167215
Impedance
Here's the impedance for both units in the pair:
View attachment 167218
View attachment 167219
As we can see, there are several visible resonances in the responses.

Distortion
76 dB SPL
View attachment 167222
86 dB SPL
View attachment 167225
View attachment 167224
Bass distortion became pretty audible around 80dB SPL and I was scared to go over 86 dB SPL.

Amplifier measurements
I disassembled the powered loudspeaker and did a few basic measurements of the built-in amplifier directly with an 8,2 Ohm power resistor.
The amplifier is based on 2 pairs of bridged TDA2030A class A/B chip amps mounted to a relatively small aluminium heatsink.

There is even a schematic of the amplifier circuit available on-line, so I drew the circuit in VituixCAD to simulate the amplifier. After measurement I compared the simulated response with the measured ones (in both cases with tone controls set to neutral / mid-point):
View attachment 167230
As we can see there is an aggressive low-cut (probably to protect the woofer) and we can also see a ~4dB high-shelf. This can be somewhat mitigated by reducing the Treble tone control by ~10-20% to be within ~1dB of the LF, but a perfectly flat frequency response cannot be achieved, e.g.:
View attachment 167231
Or:
View attachment 167232

Here's what the tone controls do at their extremes (responses normalized to mid-position response):
View attachment 167240

Amplifier response at 5W into 8,2 Ohm load:
View attachment 167237

Let's now look at HD vs input level into 8,2 Ohm power resistor with amp volume set to max:
View attachment 167233
View attachment 167234
With both channels 1% THD is reached with ~750mV input which results in 14,3V output - so power into 8,2 Ohm at 1% THD is around 28W. So perhaps the 40W per channel rating at 10% might be possible (though I think heat dissipation from the small heatsink would be very problematic at those levels).

Distortion spectrum at 5W into 8,2 Ohms:
View attachment 167238
View attachment 167239

Conclusion
Looking at the data, objectively this is not a very impressive pair of speakers. However, considering the low price (and lack of alternatives at the time) these were IMO not too bad as PC/multimedia speakers. We even used them for TV sound for a while, before buying a nicer pair - they were definitely much better for this than the built-in TV speaker. Going forward I plan to use them as a DIY project to learn more about loudspeaker design.

In case @MZKM, @pierre, @Maiky76 (or others) might be interested to do their magic, CTA-2034-A exports from VCAD are attached as well.

Hi,

Great job! Probably more measurements than this speaker ever went though during its development process...

Here is my take on the EQ.

These EQ are anechoic EQ to get the speaker right before room integration. If you able to implement these EQs you must add EQ at LF for room integration, that is usually not optional… see hints there: https://www.audiosciencereview.com/...helf-speaker-review.11144/page-26#post-800725

The raw data with corrected ER and PIR:

Score no EQ: 1.0
With Sub: 4.2

Spinorama with no EQ:

• Bad

EQ design:

I have generated two EQs. The APO config files are attached.

• The first one, labelled, LW is targeted at making the LW flat
• The second, labelled Score, starts with the first one and adds the score as an optimization variable.
• The EQs are designed in the context of regular stereo use i.e. domestic environment, no warranty is provided for a near field use in a studio environment although the LW might be better suited for this purpose.

Score EQ LW: 2.9
with sub: 5.7

Score EQ Score: 5.0
with sub: 7.7

Genius SP-HF3000A APO LW EQ 96000Hz
November222021-114846

Preamp: -2.2 dB

Filter 1: ON HPQ Fc 56.57,    0.00,    1.00
Filter 2: ON PK Fc 127.32,    -5.28,    2.45
Filter 3: ON PK Fc 995.66,    -3.11,    2.00
Filter 4: ON PK Fc 1550.41,    -5.67,    1.92
Filter 5: ON PK Fc 3227.02,    3.50,    2.17
Filter 6: ON PK Fc 6946.94,    -6.51,    1.98
Filter 7: ON PK Fc 14672.96,    -5.60,    1.26

Genius SP-HF3000A APO Score EQ 96000Hz
November222021-114307

Preamp: -1.3 dB

Filter 1: ON HPQ Fc 65.32,    0.00,    1.27
Filter 2: ON PK Fc 121.08,    -5.49,    1.58
Filter 3: ON PK Fc 971.48,    -3.11,    4.48
Filter 4: ON PK Fc 1500.26,    -5.80,    1.35
Filter 5: ON PK Fc 4880.98,    -1.75,    3.43
Filter 6: ON PK Fc 7311.52,    -7.01,    1.44
Filter 7: ON PK Fc 15032.92,    -6.55,    1.36

Spinorama EQ LW

Spinorama EQ Score

Zoom PIR-LW-ON

Regression - Tonal

Radar no EQ vs EQ score
Improvements...

The rest of the plots is attached.

 

[sweetchaos]

Great job! Probably more measurements than this speaker ever went though during its development process...

 

[pierre]

Thanks for the measurements @dominikz.
That's a case where optimising for LW being flat or for minimising the score gives very different results.
Can you listen to the 2 EQs from @Maiky76 and tell us if you have a clear preference?

I have more or less the same results.

 

[dominikz]

Thanks for the measurements @dominikz.
That's a case where optimising for LW being flat or for the score, it gives very different results.
Can you listen with the 2 EQs from @Maiky76 and tell if you have a clear preference?

I have more or less the same results.

Sure, I'll try to do it in the coming days and report back! My suspicion is that preference in such cases may be significantly impacted by the listening distance - I'll see if I can test at a couple different distances.

 

[dominikz]

Thanks for the measurements @dominikz.
That's a case where optimising for LW being flat or for minimising the score gives very different results.
Can you listen to the 2 EQs from @Maiky76 and tell us if you have a clear preference?

I have more or less the same results.

Did some listening today (nearfield only - around 0,8-1m from speakers) and, somewhat unexpectedly, I clearly preferred the score-optimized EQ. TBH I was quite surprised by this, as I expected that in nearfield conditions LW-optimized EQ would sound better.
However, with the LW optimized EQ the sound was a bit harsh and sibilant - I assume this is due to the poor directivity, where optimizing for LW caused a huge sound-power boost at ~3,5kHz.

Of course both EQ presets sound better than no EQ with these loudspeaker

Some in-room MMM measurements, and compared to spinorama PIRs:

No EQ

Notice that the left unit (passive) deviates quite a lot from the right one around 1,8-2kHz - unit-to-unit consistency is likely not very good with these.
Comparing to the spinorama I was surprised to see that the measured response matched better with the PIR than the LW in the nearfield. My room is untreated and fairly live, so that might be (part of) the reason.

@Maiky76 LW EQ

Definite improvement vs no EQ, but a bit harsh sounding.

@Maiky76 Score EQ

This one sounded the most balanced to me and was a big improvement.

Next I applied a bit of room EQ and flattened the 1,8kHz resonance in the left unit:

This of course sounded the best. I switched a bit between this and my primary nearfield speakers (Neumann KH120A), and of course the Neumanns sound much better - so I guess EQ can only get you so far. But IMHO @Maiky76 Score EQ was definitely a step in the right direction!

 

[dominikz]

Driver nearfield components:

We can see a couple things here:

• Very prominent resonances in the port NF measurement - using the VituixCAD 'Box volume' calculator indicates these are probably undamped box height resonances
• There is no real crossover - woofer is running full range and breaks up. If you open the speaker you see that just the tweeter is "high-passed" with a simple electrolytic cap

Since box resonances are very prominent (first height resonance is visible from woofer response as well) I tried lining the side, bottom and top wall of the enclosure with 3cm sound absorbing foam:

This is the measurement before and after:

As we can see, adding damping material nicely cleans up the responses (it also changes the box tuning slightly).