Sunfire HRSIW8 DSP Subwoofer Amplifier

[amirm]

This is a review and detailed measurements of the Sunfire HRSIW8 DSP Subwoofer Class D amplifier. It is on kind loan from a member. The HRSIW8 seems to have come out back in 2012 with its companion in-wall subwoofer. As best as I can tell, the retail price is US $999 but I see it on ebay for much less.

HRSIW8 comes in a compact, 1-U configuration:

It is extremely heavy for its compact size. Hefty relays click on and off when you power the unit. A rotary control changes the volume. Press it and you get into a number of menus. Alas, there is no parametric EQ is available which would be highly useful to get rid of room modes. Instead you have a crossover and different modes for "music," etc. The crossover is fully programmable as far as frequency and roll off steepness. I set the crossover frequency to highest it would go (160 Hz) for testing.

Note that this is a single channel of amplification.

Subwoofer Amplifier Audio Measurements
Before we get into our usual dashboard, let's run our frequency response test:

Hmmm. What is going on here? No matter what I did I could not get rid of that peak. Is this just made to go boom boom? Heaven help you if you have a room mode at 37 to 40 Hz as you will indeed get very boomy sound.

With the above info at hand, I ran my dashboard at 40 Hz:

Second harmonic is very low. Third harmonic at -80 dB is likely to not be audible or moot if the subwoofer won't play it.

Next I ran a power test at 4 ohms:

Just 260 watts? What happened to the other 260 watts?

Warm up did not show anything of concern:

Conclusions
I was hoping this was a general purpose subwoofer amplifier with nice parametric EQ. Unfortunately it is not. It has a completely non-flat response with no way to bring that peak down that I can find. Considering the very high price of nearly $1000, it simply is not something I can recommend that you buy.

------------
As always, questions, comments, recommendations, etc. are welcome.

It is starting to snow and we are down to freezing temps. I picked such a great time to test speakers in our garage. To avoid being frozen stiff, I am running an electric heater. These cost money to run so I hope you see the need to donate generously using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

 

[noel_fs]

imaging visiting this site all day to see if there is new measurements


and then getting disappointed

 

[amirm]

Hey, at least you didn't have to do the work to measure the thing. And then pack and ship it back to its owner!

Tomorrow will be a speaker review so cross your fingers for that....

 

[Koloth]

Seeing that you've mentioned a companion in-wall-subwoofer, is there a chance that this extremely weird frequency response was somehow designed to work well with the sub, that would on its own be equally defective?

 

[amirm]

It might keep them from getting too distorted due to lack of low-end response:

Or keeping it from cracking the paint on the surrounding drywall.

Still, the amp needs to have parametric EQ for proper room optimization.

 

[pma]

This is a review and detailed measurements of the Sunfire HRSIW8 DSP Subwoofer Class D amplifier. It is on kind loan from a member. The HRSIW8 seems to have come out back in 2012 with its companion in-wall subwoofer.

I expect they equalize poor frequency response of the "companion in-wall subwoofer". Many subwoofers are small and do not have flat LF extension, talking about speakers itself only, so the amp "helps" them then.

 

[LTig]

Second harmonic is very low. Third harmonic at -80 dB is likely to not be audible or moot if the subwoofer won't play it.

I think most subwoofers will play the 3rd harmonic (120 Hz), the only exception I can think of are band pass subs. However I'm quite sure it is totally inaudible in all home installations.

 

[Tks]

Hey, at least you didn't have to do the work to measure the thing. And then pack and ship it back to its owner!

Tomorrow will be a speaker review so cross your fingers for that....

Dont listen to him too much, I love all the reviews on this site, you get all genre of review, some impressive engineering atistry, while some utmost comedy.

 

[Francis Vaughan]

The obvious answer is a Linkwitz Transform being applied. http://www.linkwitzlab.com/filters.htm (Half way down the page.)
OTOH, the curve measured isn't the shelving response that Siegfried Linkwitz shows. But coping with the excursions inherent with such low frequencies would make the shape reasonable.

The amplifier is designed to be used with the matching subwoofer, and can't be criticized for not being general purpose. That isn't its use case or design requirements. People selling it standalone on eBay however should be clear about what it is they are selling. It is only useful to owners of the subwoofer. It is a spare part for a system.

From the Sunfire Web page:
The 520 Watt, Class D HRSIW8AMP amplifier is specifically designed to supply speaker-level power to the Sunfire HRSIW8 in-wall subwoofer, to produce stunning low frequency effects for your home theater.

From the specs for the HRSIW8CAB subwoofer:
To be used with the dedicated HRSIW8 amplifier only

Bolding mine.

The question of the power spec remains, but the frequency response does not.

 

[gattaca]

So we win and lose some. We get some good and bad news. Either way, testing like this is "very good info to have" in our back pockets. But before we toss this baby out the with the bath water.. read the fine print and manual. There's more under the hood of this AMP and we may be leaping to conclusions on without the manual and specs in hand! This is an interesting case study and little amp.

You are correct. This amp has been designed, tuned and operates with the companion sub in a very specific range and load of 4 ohms! A lot of sub makers are DSP programming their amps today to protect the sub and optimize the output. My guess the DSP is programmed to compensate the lower / weaker side of of the SUB unit. So you need to bypass all of that by using the front button to step thru the many modes: EQ mode and LFE mode specifically. I'm thinking that might remove the peaking / compensation but I do not know for sure.

The output is rated into 4 ohms. So that's maybe where they measured those "520 watts" at some specific load and frequency... (my gut says that's what the companion speaker rates to...). (This is why I like to dig into the specs.. YMMV).

• Amplifier Output 520 watts rms into 4°
• High Cut Filter 40 Hz - 160 Hz adjustable, with an LFE bypass position, and 12 to 36 dB/octave adjustable slope.
• 12 - 36 dB/octave adjustable slope
• Frequency Response 33 Hz - 150 Hz (-3 dB)

Here's the link -> https://www.sunfire.com/product/matching-1u-amplifier-hrsiw8-subwoofer-HRSIW8AMP
Here's the manual (see the modes and EQ options) -> http://resources.corebrands.com/products/HRSIW8AMP/pdf_HRSIW8AMP_manual.pdf

This amp has several modes and I think they need to be defeated to flatten that bump.. but it's never going to get passed the upper range design limit.

EQ Mode allows you to choose from five preset EQ settings to suit your listening program:
Movie, Music, Dynamic, Impact, Defeat (Flat).

LFE/SUB Mode In SUB Mode, the Crossover Slope and Crossover Frequency can be adjusted, and so these menus are available. In LFE mode, the Crossover Slope and Crossover Frequency cannot be adjusted, and so these menus are hidden. The crossover adjustment is then left to the Home Theater preamplifier.

This AMP is loaded with features too some of us long to see in amps / see the specs: XLR inputs, 12V triggers, DSP processing, Remote controls, ...

So some things to think about are should things like this be taken into account when evaluating, testing or measuring? Every AMP we see is not designed for a 20-20kHz.. in fact the Crown XLS2502 is rated at 1kHZ. So everyone is playing with these figures when they can... sadly that's a whole other thread! So if we just consider this AMP is driving a SUB in a limited frequency range does that change your gut reactions? Is is delivering on what the designers intended? I mean it's not a general-purpose 20-20kHz full range amp - never intended to be.

So does this make us think a bit differently / out-of-the-box? Hmm.. I am still very disappointed with that claimed power measurement.... who knows maybe its into 2 or 3 ohms - they really don't say which always makes me wonder what details may have omitted. YMMV Peace.

 

[direstraitsfan98]

So we win and lose some. We get some good and bad news. Either way, testing like this is "very good info to have" in our back pockets. But before we toss this baby out the with the bath water.. read the fine print and manual. There's more under the hood of this AMP and we may be leaping to conclusions on without the manual and specs in hand!

You are correct. This amp has been designed, tuned and operates with the companion sub in a very specific range and load of 4 ohms! A lot of sub makers are DSP programming their amps today to protect the sub and optimize the output. My guess the DSP is programmed to compensate the lower / weaker side of of the SUB unit. So you need to bypass all of that by using the front button to step thru the many modes: EQ mode and LFE mode specifically. I'm thinking that might remove the peaking / compensation but I do not know for sure.

The output is rated into 4 ohms. So that's maybe where they measured those "520 watts" at some specific load and frequency... (my gut says that's what the companion speaker rates to...). (This is why I like to dig into the specs.. YMMV).

• Amplifier Output 520 watts rms into 4°
• High Cut Filter 40 Hz - 160 Hz adjustable, with an LFE bypass position, and 12 to 36 dB/octave adjustable slope.
• 12 - 36 dB/octave adjustable slope
• Frequency Response 33 Hz - 150 Hz (-3 dB)

Here's the link -> https://www.sunfire.com/product/matching-1u-amplifier-hrsiw8-subwoofer-HRSIW8AMP
Here's the manual (see the modes and EQ options) -> http://resources.corebrands.com/products/HRSIW8AMP/pdf_HRSIW8AMP_manual.pdf

This amp has several modes and I think they need to be defeated to flatten that bump.. but it's never going to get passed the upper range design limit.

EQ Mode allows you to choose from five preset EQ settings to suit your listening program:
Movie, Music, Dynamic, Impact, Defeat (Flat).

LFE/SUB Mode In SUB Mode, the Crossover Slope and Crossover Frequency can be adjusted, and so these menus are available. In LFE mode, the Crossover Slope and Crossover Frequency cannot be adjusted, and so these menus are hidden. The crossover adjustment is then left to the Home Theater preamplifier.

This AMP is loaded with features too so of us beg to see in amps / see the specs: XLR inputs, 12V triggers, DSP processing, Remote controls, ...

So some things to think about are should things like this be taken into account when evaluating, testing or measuring? Every AMP we see is not designed for a 20-20kHz.. in fact the Crown XLS2502 is rated at 1kHZ. So everyone is playing with these figures when they can... sadly that's a whole other thread! So if we just consider this AMP is driving a SUB in a limited frequency range does that change your gut reactions? Is is delivering on what the designers intended? I mean it's not a general-purpose 20-20kHz full range amp - never intended to be.

So does this make us think a bit differently / out-of-the-box? Hmm.. I am still very disappointed with that claimed power measurement.... who knows maybe its into 2 or 3 ohms. YMMV Peace.

This kind of approach to things doesn't seem to ever go down well here, since Amir sees it as directly attacking his measurement methodology.

 

[gattaca]

Sorry, my post is not meant to come off as attacking Amir or his approach at all!

There's no absolute right and wrong - only the facts as designed and measured.

Just as the AMP was designed specifically for a range, so are what's being tested and how.

We just need to frame the context of both. Peace.

 

[Duckeenie]

Dont listen to him too much, I love all the reviews on this site, you get all genre of review, some impressive engineering atistry, while some utmost comedy.

Not sure if my seeing his comment less literally is correct or you have him nailed. Either way, If it weren't for people viewing things differently, we would still believe that the world is round.

 

[anmpr1]

Something like this can reasonably be evaluated in conjunction with its in-wall subwoofer. Otherwise, is there any use in taking time on it? Even with it's dedicated sub, I don't know how one could 'measure' the combo in a lab setting; it's purpose is integration into a wall. Outside of an installation, what can you tell? Is it possible to draw conclusions otherwise? Not an install guy, I'm pretty ignorant of the techniques used by installers. I guess this stuff goes in when you are building your house?

I presume all the modern Sunfire stuff is post-Carver?

 

[WesParker]

Something tells me that if "flat" mode is in the same menu as "dynamic" mode, he probably tried it. My guess is that Sunfire designed it to work with a dip in response from the smallish drivers and that their expectation is it needs that bump to get the package to "flat." Also, I agree with his assessment, that if you are buying this off ebay to power a subwoofer, it probably isn't the best idea. Unless you can design an enclosure that needs a similar boost. And then you'd still be missing any kind of eq, or contending with an extra eq if you put one in front of the amp.
Luckily if you still want to buy it, you won't be contending with Amir running up the auction price.

 

[Deleted member 2944]

A dedicated amplifier for a dedicated woofer. The EQ curve is typical for a closed-box system where the enclosure is quite a bit smaller than would be nominal for the woofer used. The proper test procedure would include the woofer as well with a close-up microphone measurement.

I don't know why this warrants the panthers head cut off. Incorrect evaluation.

Dave.

 

[audioBliss]

Even if it's a dedicated EQ why would you do it this way and also why such a high Q, high gain EQ like that? +12dB at 37Hz?? 37Hz is not even a low frequency for a subwoofer.

 

[BostonJack]

The obvious answer is a Linkwitz Transform being applied. http://www.linkwitzlab.com/filters.htm (Half way down the page.)
OTOH, the curve measured isn't the shelving response that Stanley Linkwitz shows. But coping with the excursions inherent with such low frequencies would make the shape reasonable.

The amplifier is designed to be used with the matching subwoofer, and can't be criticized for not being general purpose. That isn't its use case or design requirements. People selling it standalone on eBay however should be clear about what it is they are selling. It is only useful to owners of the subwoofer. It is a spare part for a system.

From the Sunfire Web page:
The 520 Watt, Class D HRSIW8AMP amplifier is specifically designed to supply speaker-level power to the Sunfire HRSIW8 in-wall subwoofer, to produce stunning low frequency effects for your home theater.

From the specs for the HRSIW8CAB subwoofer:
To be used with the dedicated HRSIW8 amplifier only

Bolding mine.

The question of the power spec remains, but the frequency response does not.

"stunning low frequency effects" seems to admit a lot of booming, cannonballs rolling around, etc. not associated with high sound quality.

 

[Deleted member 2944]

Even if it's a dedicated EQ why would you do it this way and also why such a high Q, high gain EQ like that? +12dB at 37Hz?? 37Hz is not even a low frequency for a subwoofer.

That's how (one way of doing it) you equalize a woofer that's in too small a box. That electrical response doesn't translate to acoustic response is what I'm saying. If you made an acoustic measurement at the woofer cone you would see something much closer to a flat response, I suspect.

Dave.

 

[gattaca]

^^^ Absolutely. Using this AMP with the speaker it's designed for would be an "active speaker" setup where the AMP's DSP has been programmed to compensate for deficiencies in the woofer's delivery.

But unlike most, this amp's dsp has the means to disable that programming (I think) with the EQ Mode and LFE/SUB mode I posted earlier. Gut says those might remove that large bump as measured. However, the watts out at 4 ohms remains disappointing for a SUB AMP, IMHO. This is why I'm betting the marketing figure comes from something lower or something at a specific frequency - those pesky details.

FWIW, we are seeing more "active" speaker systems on the market (mass market) for this very reason. They can better control the entire delivery instead of having to make the whatever part play nice with everything under the sun. It's like saying AMP A sucks for driving planar speakers but is great for driving Y Why? b/c they may be more efficient speakers which need less power? Does AMP A then suck b/c it doesn't do both well? That is where a matter of perspective is key.