"Aliexpress" Subwoofer Plate Amp Review

[Azrael]

The problem with the high-pass filter is that it is overshooting and is undocumented as far as response. You sim your subwoofer, then go and test it with this amp and get something different because the sim assumes flat amplification (perfect voltage source).

Yes, exactly. And I don’t need to simulate that to reach this conclusion either; see above.

However, one might infer from the review that a high-pass filter is generally unnecessary for a subwoofer. But that would be wrong. And I wanted to pre-empt that possible misunderstanding.

 

[DWPress]

I use a HP filter @ 18Hz on my big sub too because without it the decay in my room is very annoying. The little SVS seems to have one already baked in but doesn't naturally get down low with an F3 of around 25Hz.

Full agreement with Amir that I'd want this information before I ordered a plate amp though and that it would be more difficult to model without this knowledge and very disappointing to get it and discover later - usually weeks or months later when a project finally comes together.

I've got a couple old MCM plate amps sitting in the closet I could run through their paces with Mutitone perhaps but I'll hold off any further judgement on this one until a few more plate amps like the Dayton are tested. I really like the XLR pass through feature on this one though. Thanks for the review Amir!

 

[levimax]

Looking at the FR graph printed on to amp the high pass does appear to be documented?

 

[amirm]

Looking at the FR graph printed on to amp the high pass does appear to be documented?

It is kind of there but the scale is large so it is easy to ignore.

 

[mhardy6647]

I would LOVE to see a test of the Dayton Audio SPA500DSP that is supposedly identical to the amp used in the Wilson Lōkē subwoofer.

Dayton Audio SPA500DSP
Wilson Lōkē Subwoofer

FWIW and apropos of almost nothing -- I've got its little "250 watt" brother (or sister, or sibling, or whatever) on my (very) seldom used 2 x 15" subwoofer.




I "built" a pretty embarrassingly crude box for it upon receipt. Don't judge me!

 

[DWPress]

I've seen (and built) worse.

edit: is that the crossover on top of the speaker on the left?

 

[john61ct]

Yes I would always want a rumble filter, very steep slope just below the acoustic bottom drop off of the sub. So maybe 15Hz with a bottom-most trueSub.

Why let impossible energy affect linearity?

If I was using active DSP then I would want to be able to disable any frequency management in the power amp itself.

My expectation for a plate amp would be active DSP, at least as good quality as miniDSP included built in.

Preferably with a line-level output for splitting the channel, crossover tuning of at least one more external enclosure.

Ideally with the ability to coordinate config to others, at least L/R mirroring for two channels.

Tinysine, Wondon, et al should be able to be very competitive in these higher-power sub markets

 

[solawind]

I use https://www.audiosciencereview.com/...tpa3255-amplifier-kit-480-1-29a-review.50283/ for my DIY subwoofer because I am too lazy to look for something more suitable. It handles my 2-ohm driver perfectly. It's so powerful that it's hard to hold the driver in your hands during testing.
So I guess I have one of the cleanest subwoofers out there - although, for a subwoofer, that doesn't really matter, lol.

 

[phoenixdogfan]

I don't know what the rationale could even be for an undocumented high pass filter at 60 hz in a subwoofer plate amp. Looking at Amir's graph I don't see how any woofer driven by this amp could play at 20 hz. which kind of defeats the purpose of having a subwoofer in the first place. It's also underpowered. My SVS SB-2000's have a 600 wpc amp in them. 200 wpc just seems a little anemic. The 61 db Sinad that's looks noise dominated is probably inaudible given the ear's insensitivity at the frequencies this amp will be reproducing. Finally, why couldn't they have made it under $100? When I shop Ali or Temu I want to feel like I'm stealing, and this doesn't quite feel like stolen property to me.

As always, Amir, thanks for the great review.

 

[Azrael]

I don't know what the rationale could even be for an undocumented high pass filter at 60 hz in a subwoofer plate amp.

Well, if I start from the top of this strange peak, I get a -3 dB point below 30 Hz. How did you arrive at 60 Hz?

*edit*:
It occurs to me that it’s worth noting: the bandwith of the vertical scale of this diagram is much smaller than that of typical loudspeaker frequency response diagrams. Here, the vertical bandwidth of the diagram is about 10 dB, whereas for loudspeakers it’s usually 50 to 60 dB. This may make the graph look worse than it actually is.

To illustrate this, I simply scaled the height of the diagram down to one-fifth:

 

[phoenixdogfan]

Well, if I start from the top of this strange peak, I get a -3 dB point below 30 Hz. How did you arrive at 60 Hz?


View attachment 546263

*edit*:
It occurs to me that it’s worth noting: the bandwith of the vertical scale of this diagram is much smaller than that of typical loudspeaker frequency response diagrams. Here, the vertical bandwidth of the diagram is about 10 dB, whereas for loudspeakers it’s usually 50 to 60 dB. This may make the graph look worse than it actually is.

To illustrate this, I simply scaled the height of the diagram down to one-fifth:

View attachment 546266

How about because it starts rolling off at 60 hz?

 

[Azrael]

How about because it starts rolling off at 60 hz?

As far as I know, the cutoff frequency of a high-pass filter is defined as the frequency at which the signal level has decreased by 3 dB as it passes through the filter.

*edit*:
If you look at the graph which I've scaled down vertically to one-fifth its original size it actually looks as if the high-pass filter is set even lower and that a peak filter ("bass boost"?) with its peak at about 60 Hz has been implemented.

 

[Timcognito]

I "built" a pretty embarrassingly crude box for it upon receipt. Don't judge me!

Yours looks okay but compared to this one, I wouldn't worry about it. Some real Spinorama there

A Call For Humor!

www.audiosciencereview.com

 

[Cote Dazur]

I would like to be guided to a good thread discussing high frequency bypass settings practice.
I have always set my high pass to the lowest setting only playing with volume and placement of my subs.
My goal is to provide support to my 2 full range tower speaker 12 inch woofers. In other word use them as subwoofer. So I am only interested in frequency starting from 40hz and down from my subs.
I only listen to music in a fairly large open space area on that system.

 

[SuicideSquid]

I almost bought a couple of these recently for a stereo subwoofer build I'm working on. Ended up going with a Douk amplifier and looking at these numbers, very glad I did!

 

[Dave TR3A]

FWIW and apropos of almost nothing -- I've got its little "250 watt" brother (or sister, or sibling, or whatever) on my (very) seldom used 2 x 15" subwoofer.

I have SPA250DSP plate amps in both of my Bill Fitzmaurice-designed THTLP subwoofers. I ended up not using the amp’s DSP capabilities.

 

[Grenadine]

From the product listing:

"Introduction:
This is the new subwoofer amplifier board in our store. Many buyers strongly recommend us to produce a high-quality subwoofer amplifier board designed for home theater. After referring to many international first-line brand gun amplifier boards, the chief engineer of a foreign-funded enterprise for more than ten years has designed two high-quality subwoofer amplifier boards. One is the rated power output of 350W, and the other is the rated power output of 200W. The power supply adopts a high-efficiency half-bridge power supply, with 120V and 230V transfer switches, suitable for global use, and the power supply margin is quite large, and the ripple is lower than the traditional transformer power supply. The power amplifier output also uses a MOS high-current tube output, this model truly achieves 1% distortion of 350W, and the control is amazing. The front stage adopts the current leading technology in the subwoofer industry, using dynamic EQ algorithm, high speed, low dive, and high control. A low-cut is also designed, which cuts all the frequency below 15Hz and converts the energy to the frequency range of 25Hz-60Hz, which makes people sound endless and full of energy. This gun board is made of solid materials, with an aluminum back plate, and almost no noise at the end. It is a rare subwoofer power amplifier board for home theaters."

Also, while the "ethics" amp has been with Amir, I've been using this sub amp. Has dsp manual controls. Highly recommend for sub duty. Stable to 2 ohms, 1000 watts @ 2.7 ohms. Tested/assembled in Irvine, CA:

HTB-700

Mono Block Standalone Subwoofer Amplifier Home Theater (HT) STABLE at 2 ohms 1000W @ 2.7 ohms 700W at 4 ohms 350W at 8 ohms 53 VRMS (75 Vp) at Hi-Z Subwoofer DSP Controls OVERVIEW: This product is uniquely designed to produce high power output at extremely low frequencies, making it perfect for...

www.speakerpower.com

 

[mhardy6647]

I have a SPA250DSP plate amps in both of my Bill Fitzmaurice-designed THTLP subwoofers. I ended up not using the amp’s DSP capabilities.

Me, too, as it happens.
But it's nice to have them, just in case, no?

 

[Azrael]

Has dsp manual controls.

I can't find any indication that this device has a DSP built in. Based on the description, the high-pass filter also doesn't seem to be freely configurable, as would be possible with a DSP.

 

[amirm]

This is a purely analog amp.