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RBH SI-1010 & SA-500DSP Measurements and Analysis

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We were curious to see how the SI-1010 subwoofer measured so we took it outside and performed a groundplane frequency vs output test. We also put the SA-500 amplifier on the bench with our Audio Precision APx585 Audio Analyzer.

SI-1010P Subwoofer Measurements

We positioned the SI-1010 sideways on the floor with the microphone 1 meter away equadistant from both drivers. The front panel cover was removed so we could test for the highest output possible. RBH informed us with the panel removed, the SI-1010p will play about 1.5-2dB louder than with it installed.  If you don't need to hide the woofers for aesthetic reasons, then we'd recommend removing it.

RBH SI-1010 SPL vs Frequency 

RBH SI-1010 SPL vs Frequency Response @ 1 meter Groundplane

The SI-1010 sealed narrow enclosure somewhat prevents it from digging as deep and loud to comparably priced large box subwoofers.  The measurements above did however demonstrate that this sub has quite a lot of output for something you can conveniently hide in a ceiling or a floor, something you can't do with a big bulky box subwoofer.  The -3dB pt of the system was 40Hz with NO EQ applied but virtually ever sub on the market employs low frequency boost to yield better extension.  As is, the SI-1010 played loud and clean with no hint of distress.  It stopped getting any louder as a result  of the limiter circuit build into the SA-500DSP.  If I had a more powerful amp, I am confident this sub would have a good deal more output to reveal.  The SI-1010 is flat all the way to almost 400Hz making it an ideal sub to blend with small satellite speakers that require a higher than 80Hz high pass filter.

RBH SI-1010 SPL with EQ Correction

RBH SI-1010P SPL vs Frequency @ 1 meter Groundplane with EQ

Bassaholic LargeWith EQ applied, I was able to lower the bass extension to a -3dB pt of around 25Hz which held up even at high SPL output.  However, due to the long sweep tones, it tripped the self-resettable fuse in the subwoofer that protects the driver from excess current when sweeps exceeded 110dB.  Although this is a bummer on the test bench, it's not something that ever happened in real world listening tests with real program material.  It is actually a good design compromise to increase reliability.  The one thing you don't want is to blow a driver once you have this box installed in your ceiling or floor.  I checked with RBH and since this products inception over 10 years ago, they've had only a few unit requiring service in the field due to a blown driver and that was before the SA-500 amp was being used to power it.

If you want your SI-1010 to exhibit the frequency response measured above, than you'll need to set the EQ boosts in the SA-500DSP amp to the following settings:

20 Hz: +6dB
25 Hz: +6dB
31 Hz: +6dB
40 Hz: +3dB

Using the SA-500 amplifier with EQ boost, the SI-1010P was able to earn our large Bassaholic Subwoofer Rating which is quite astounding for an in-wall type subwoofer product. 

SA-500DSP Amplifier Measurements

The SA-500DSP amplifier sports a Class D output stage with a linear power supply.  We were big fans of the original SA-400 amp that RBH has been using for their other in-wall or externally powered subwoofers so we were curious as to how the more compact but up to date SA-500DSP would perform.  On paper, the SA-500DSP is rated at 100 watts (500 watts RMS @ 4 ohms) more output compared to the SA-400 and it also has a host of DSP options like adjustable PEQ and subsonic filters, as well as adjustable crossover and programmable EQ settings.  More features for sure, but what about performance?

Frequency Response

SA-500 Frequency Response

RBH SA-500 Frequency Response

The SA-500DSP is clearly NOT a fullrange amplifier. In fact, I measured a -3dB of about 2kHz so this amp is for bass duties only.  I checked the Low Pass filter response and found the unit measured a -3dB pt of the crossover you selected (ie. 80Hz) with the desired slope (in this case I had it set to 24dB/oct).  I would have liked to see the crossover point selected actually be the -6dB pt with the slope set to 24dB/oct as it is with THX certified products when matching subwoofer and satellite systems with a HPF slope of 24dB/oct in the AVR bass management circuit but it shouldn't be too hard to dial in a proper response since both the frequency and slope are adjustable on the SA-500 amplifier ( 9 bands and slope from 12 to 36 dB/oct).

SA 500 Programmed EQ modes

RBH SA-500 Pre-Programmed EQ Settings

Shown above is what the pre-programmed EQ settings does to frequency response of the amplifier and corresponding subwoofer attached (in this case the SI-1010).  If one of these modes don't suite your needs, RBH does offer adjustability of +- 6dB for its fixed 9 band EQ of frequencies of 20, 25, 31, 40, 50, 63, 80, 100 and 125Hz.  I tested these and they worked as expected but would have preferred adjustable frequency and Q for finer tuning.

Power & Distortion Tests

I was able to hit the 500 watts continuous power rating into a 4 ohm load for the bandwidth of operation of concern.

RBH SA-500 Power Vs Frequency

RBH SA-500 Continuous Power vs Frequency

RBH SA-500 Psweep2
RBH SA-500 Power Sweep Test

Sweeping the SA-500DSP at 200Hz for power vs distortion revealed the actual 500 watt rating was hit at a rather high distortion of 0.4% THD + N.  This is acceptable at bass frequencies but far from state of the art as far as full range amplifiers are concerned. Using a CEA-2006 burst test, I was able to get 540 watts into 4 ohms at 1% THD +N for our dynamic power testing. 

RBH SA-500 FFT

RBH SA-500 FFT Distortion Analysis

There is no kind way of saying that this measurement is mediocre.  While the residuals at 1 watt are clean, the noisefloor of this amp just isn't all that stellar.  It should be a good 20dB lower than this.  However, I only found this to be slightly detectable as background noise if I stuck my head within a few feet of the connected subwoofer when it was turned on with no program material running through it in a quiet room.  In this day and age there should be no reason for this so we hope RBH can improve upon this in future iterations of the amplifier.  However, for long cable runs, we recommend using twister pair to minimize noise pickup since this amp seems a bit more sensitive to it than comparable linear AB amps we've previously tested.

 

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Recent Forum Posts:

AcuDefTechGuy posts on May 26, 2017 12:40
ParadigmDawg, post: 1189233, member: 21334
I was able to place the sub in my sweet spot it's just 14 ft higher then it was but it's still a good spot for it.
LOL.
ParadigmDawg posts on May 26, 2017 10:37
lovinthehd, post: 1189143, member: 61636
Just what you said was what I wanted you to share, especially with your having had better subs before that….
Then my work is done here…lol…

I was able to place the sub in my sweet spot it's just 14 ft higher then it was but it's still a good spot for it.

Don't underestimate the difficulty in getting a 75 lb sub up a ladder and across the attic and screwing it in place without dropping it through the Sheetrock. It was not fun.



Here is what you see of it:

lovinthehd posts on May 25, 2017 21:11
ParadigmDawg, post: 1189119, member: 21334
What would I say? I went from Paradigm Studio 100's and two SVS PB13 Ultras, then got rid of one SVS, then got rid of the Paradigms and went in-ceilings with the SI 1010.

Does it sound as good as my real system, nope but 90% of the time, for listening to music at normal volumes and watching movies below reference level, I am very pleased.

The sub actually impresses me at times. A second one will likely be really, really nice and may just happen at some point. In the meanwhile, I am way more pleased than I ever thought I would be and guest whom don't see or expect a system, are blown away. I get way more comments on how nice it sounds than I did when you could see everything.

Look how clean this is compared to the old system






Just what you said was what I wanted you to share, especially with your having had better subs before that….
ParadigmDawg posts on May 25, 2017 17:51
lovinthehd, post: 1188920, member: 61636
Maybe @ParadigmDawg can comment, I believe he installed one of these in his living room during a remodel….
What would I say? I went from Paradigm Studio 100's and two SVS PB13 Ultras, then got rid of one SVS, then got rid of the Paradigms and went in-ceilings with the SI 1010.

Does it sound as good as my real system, nope but 90% of the time, for listening to music at normal volumes and watching movies below reference level, I am very pleased.

The sub actually impresses me at times. A second one will likely be really, really nice and may just happen at some point. In the meanwhile, I am way more pleased than I ever thought I would be and guest whom don't see or expect a system, are blown away. I get way more comments on how nice it sounds than I did when you could see everything.

Look how clean this is compared to the old system





lovinthehd posts on May 24, 2017 17:20
Maybe @ParadigmDawg can comment, I believe he installed one of these in his living room during a remodel….
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