Sunfire HRSIW8 DSP Subwoofer Amplifier

[anmpr1]

Here's the FR of the sub measured at the Sound n Vision site. Compare with amp... In any case, the combination does not seem to be very good value for the dollar, even if you can get them to work well in your room.

https://www.soundandvision.com/content/sunfire-hrs-iw8-wall-subwoofer-and-amp-test-bench

 

[Francis Vaughan]

(wrt the amp measurement versus a LT response)
I think what you are seeing is a combination of two things. The different scale of the graphs, and the effect of a second filter intended to prevent over-excursion a low frequencies. LT filters typically provide boosts of the order of 10 - 18 db. So the peak of 12 db at 37Hz is perfectly reasonable. As is the order of the filer. The lack of a dip in the response would suggest that the subwoofer was intrinsically designed with a reasonable Q, and there was no need to correct for a pre-existing hump. That leaves the steep drop at frequencies below the rise. That I would think isn't part of the LT design per-se, but rather is simply an applied limit to the low end response to avoid destroying the drivers. It is imposing the new response that the subwoofers provide. It is unfortunate that visually it looks like a nasty peak. But in concert with the subwoofer design I would feel comfortable it is actually correct. The above measurement seems to confirm this view.

Further measuring the system as a whole will reveal the truth of the matter. (Although I hope there is approriate compensation available to cope with the intended mounting of the sub-woofer in the measuring system. I would imagine there is.)

 

[gattaca]

Thank you for the link. The comments are right about the price to retail value. Almost no one pays retail for these items - except in a no holds barred no budget custom built installations. FWIW, these AMPs sell for $250-400 on eBay.. with no sub attached. The frequency response from that graph is right in line with the areas I focused on. BUT then it fails to deliver the advertised power of at 4 ohms to drive those pistons. So it will end backup on eBay. I'm sure all of the ASR readers will enter into a massive bidding war for the unit. (ROTFLMAO).. Cheers and Peace.

https://www.soundandvision.com/content/sunfire-hrs-iw8-wall-subwoofer-and-amp

 

[anmpr1]

BUT then it fails to deliver the advertised power of at 4 ohms to drive those pistons.

Amp defective? Is that a possibility? Why would they ad it at 4 ohm?

This sort of thing is too complicated for me--I mean architectural speakers. With a sub box you definitely have to move it around in order to find an optimum location. I don't know how installation pros work it out. Cutting a hole in your wall is a pretty radical thing. How do they know the correct location for optimal sound? I'm sure there is electronic equalization. But still...

 

[Deleted member 2944]

I have to admit I don't know that much about LTs but I have played around with them and I don't remember ever seeing a peaked curve like that. I know what you are saying but what I'm saying is that that's usually not how a Linkwitz Transform looks..at least with any sort of descent subwoofer.

Folks seem to be talking/explaining about a Linkwitz Transform. Good information, but that's not what we have here in the Sunfire amp. This is simply a peak filter with a defined center frequency, gain, and Q. You can tell by the symmetrical shape of the response.
I see no indication it's implementing anything like an LT transfer function.

Dave.

 

[FrantzM]

I align myself with the views that this amp is a companion to a specific subwoofer and as such should be tested in a system context. We may debate for years if we want but what can be inferred from this review is that one shouldn't buy this product to be used with anything else but its companion subwoofer.
OTOH it seems incapable to produce the advertised 500 watts but this may not be of concern if it manages to produce the advertised SPL with its own matched subwoofer.
I suppose the best would be to test those 2, together. If possible.

Peace


P.S.
Just read anmp1's post . The combo would not have fared better. This thing deserved half a panther

 

[Francis Vaughan]

Folks seem to be talking/explaining about a Linkwitz Transform here. Good information, but that's not what we have here in the Sunfire amp. This is simply a peak filter with a defined center frequency, gain, and Q. I see no indication it's implementing anything like an LT transfer function.

Dave.

As I described above, I don't see the application of a LT plus a steep rolloff as being inconsistent with the response measured. However you want to charaterise it, if the resultant parameters are consonant with this way of generating the response, that is what it is. If it turns out that implementation of the required parameters is easilly effected with a simple peaking filter, then why not? In a DSP this will be much easier. All filters are defined with a frequency, gain and Q. A peaking filter is simply symmetric. In order for this to be a LT section, the order, Q, and frequency would be chosen by deriving them from the subwoofer's Fs and Qt. I would argue that if this is the case, it is an LT filter. The shelving nature of the LT filter section is not required, especially if you need to apply some excursion limiting.
What matters is the overall system response, and as seems to be measured above, it is exactly what the specifications of the system claim it should be.

 

[gattaca]

Amp defective? Is that a possibility? Why would they ad it at 4 ohm? ... How do they know the correct location for optimal sound?

Doubtful. I sent Amir the brand new never outta the box except in my hands AMP.

As for the locations, in installations where these may be typically installed, the home owners tend to care more about the speakers disappearing and blending into the walls than fully optimal sound. These are a compromise to do both. We are talking 7-8 figure houses with AV budgets in the 5-6 figures. YMMV.

 

[Deleted member 2944]

Francis,

There's no way to fully characterize this electrical response to the acoustic response because we don't have that Sunfire woofer to measure the combination with.
Whether this particular filter was designed to implement some sort of "hybrid" LT response, I don't know. I suspect not.

It looks to me like a crude bass boost scheme approximating the necessary EQ to extend the system LF response and bring the Qtc to a higher value. The electrical roll-off on the bottom end is obviously not what a shelving second-order low-pass filter would look like. But, generally, it probably works okay (in situ) because room gain accentuates response and there's no need to continue with electronic equalization at very low frequencies.

I can't see any reason to belabor the point further. Amir (and a few others) didn't understand the reasoning for this type of EQ, but I think we've explained it pretty well.

Dave.

 

[audioBliss]

Seems like a pretty useless subwoofer to me - nothing below 40Hz. Imo it's not a subwoofer at all and this amp looks about as useless - good match.

 

[jasonhanjk]

Even Though specs mention 4 ohm, I went to check the companion subwoofer.
That sub model doesn't include any impedance spec. Frankly I'm not surprise.

According to the power results in the measurement, calculating backwards; changing 4 ohm to 2 ohm will definitely get the rated power.
Anyone who own that sub care to measure using a multimeter?

 

[gattaca]

^^^ I do not own that speaker... but I think you are dead on target. The thing that chaps my *@*@( is that the AMP's manual clearly stated the rated power into 4 ohms, not 2... If they'd done that, it would be more transparent (and accurate)...

 

[xykreinov]

This would have definitely made my "Most Craptastic Audio Products of 2020" list if I'd remembered it. I probably would have started the reason off with something like, "Starting 2020 and this list off with a bang, or more fittingly, a BOOM, with the Sunfire HRSIW8 DSP Subwoofer Amplifier!"

 

[gattaca]

I stumbled on this one a few weeks back. It appears this little SUBWOOFER AMP is also being sold by RBH Sound too. These units appear identical in features, functions, displays, back panels, ... There are not too many makers of a 1U DSP SUBAMP.

FWIW, I've used 3 of these for several years driving ~3.5lb linear motors (buttkickers). They are being fed ULF from films and they do a good job really thudding/thundering my floor quite nicely. Of course, this is an "off label" use!

As we all concluded, YMMV with other uses.

RBH units -> https://rbhsound.com/img/manuals/manual_sa250dsp_sa500dsp.pdf

Sunfire/Nortek -> http://resources.nortekcontrol.com/products/HRSIW8AMP/pdf_HRSIW8AMP_manual.pdf

Stay safe, stay alive. Peace.

 

[AudioArchitech]

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:

View attachment 45769​

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:

View attachment 45770

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:

View attachment 45772

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:
View attachment 45773

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

Warm up did not show anything of concern:

View attachment 45774

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/

I'm guessing that you missed trying it with the EQ setting set to FLAT (and maybe needs to be in Sub mode as well)

 

[Trdat]

We never really got the punchline from this thread. I have been looking into the threads on amplifiers that power subwoofers to see if I can find anything in the comments on the audibility between say an amp that measures such as this compared to something potentially decent like a Hypex NC2K(although that is not measured) if and only using it for subwoofer purposes.

If we are only using for under 130hz would say a decent amplifier provide us with any audible improvement? What improvements can we get?