Hifi experts' advice wanted - ohm/wattage question

[mindforge]

I'm ashamed to admit I never paid attention in physics and have no knowledge of electricity. However I am into hifi and AV.

I would like to add a bass shaker (passive subwoofer) to my cinema room.

It's a tactile transducer, so my plan is to fix some wood to the bottom of the sofa, attached to the two cross struts and then fix the bass shaker to that for good vibrations.

However these are far more popular in the US than here so the options are much more limited.

What I'd like advice on is whether this 100w amp would power sufficiently (but not overpower) this bass shaker. If I like the effect could potentially add another that I understand can be daisy chained. The amp would be connected to a spare subwoofer out on the main AVR. The amp has a cut over dial as well as volume, so could be tweaked as well as the crossover on the AVR itself.

Bass shaker:
https://www.amazon.co.uk/gp/product/...PE2O9HT9&psc=1

Amp:
https://www.amazon.co.uk/gp/product/...O6BEJ1QF&psc=1

[mondie]

On the face of it yes, it looks ok. The Aurasounds rated at 4 ohm 50w max and the amplifier is 100w into 4 ohms (Class D hence why its compact). However, the usual caveat applies to anything audio - the specs are only half the story. I recall a mate messing around with shakers years ago and I recall he found them quite power-hungry. It all comes down to your listening volume, the effectiveness of your mounting and expectations. The amp could be the weak link but on paper, it should work> Your buying from Amazon so you can return it if it's too weak or the specs turn out to be too optimistic.

[mindforge]

On the face of it yes, it looks ok. The Aurasounds rated at 4 ohm 50w max and the amplifier is 100w into 4 ohms (Class D hence why its compact). However, the usual caveat applies to anything audio - the specs are only half the story. I recall a mate messing around with shakers years ago and I recall he found them quite power-hungry. It all comes down to your listening volume, the effectiveness of your mounting and expectations. The amp could be the weak link but on paper, it should work> Your buying from Amazon so you can return it if it's too weak or the specs turn out to be too optimistic.

Thank you. What does Class D mean?

The wonderfully named Nobsound do a 300w one but I read somewhere about not overpowering these shakers. My understanding is the Butt Kickers are much more power hungry as are the Earthquake ones.

[jimp]

Calling Rod!

[paskinner]

The only issue I can see is that a 4ohm load will draw twice as much current , compared with 8 ohms, and thus potentially give the amp a harder time. But, as already said, the only useful test is to try it. Mind you, I would prefer a powered sub, because extra grunt is always fun when driving bass units.
A class d amp operates digitally, rather than in analogue mode. It will run cool and is very compact because so efficient. Some enthusiasts think they sound less good than a conventional analogue amp. But in truth, a good class D is fine.

[mondie]

Class D is not digital, that's a misconception that comes from its name (D = digital). Class D is simply a typology that use transistors as high-speed switches rather than linear devices. Modern improvements in transistors have seen this class of amplification become very common in the last decade or so, typically employing MOSFETs. One advantage it has over other classes of amplification is efficiency, class D amplifiers can be made much smaller and generate a lot less heat. Ideal for your application really.

[adrianw]

To fully understand the impedance of a speaker you need to see the impedance curve, the quoted figure is when it is idle, in the OPs case the efficiency of the unit is important so worth taking a look if quoted.

[mindforge]

The only issue I can see is that a 4ohm load will draw twice as much current , compared with 8 ohms, and thus potentially give the amp a harder time. But, as already said, the only useful test is to try it. Mind you, I would prefer a powered sub, because extra grunt is always fun when driving bass units.
A class d amp operates digitally, rather than in analogue mode. It will run cool and is very compact because so efficient. Some enthusiasts think they sound less good than a conventional analogue amp. But in truth, a good class D is fine.

Thanks. I have a powered sub already (BK Xls400), this is a tactile transducer to mount under the sofa!

[Rod]

Late to this, I can't see a problem and Mondie's reply is spot on. Adjust the volume tentatively at first and don't over crank it up too high. Class D amps can clip quite quickly. I don't know what protection is in these.

[mindforge]

Late to this, I can't see a problem and Mondie's reply is spot on. Adjust the volume tentatively at first and don't over crank it up too high. Class D amps can clip quite quickly. I don't know what protection is in these.

Thanks very much. Could it take two of the shakers do you think? Not sure whether would wire in parallel or serial?

[mondie]

I would not run two shakers off the amp, you would be at risk of damage. As Rod has said Class D amps clip with little warning and once they are overloaded their distortion levels skyrocket. The amp you are proposing is cheap so you should just get two.

[mindforge]

I would not run two shakers off the amp, you would be at risk of damage. As Rod has said Class D amps clip with little warning and once they are overloaded their distortion levels skyrocket. The amp you are proposing is cheap so you should just get two.

Got it, thanks.