Will this amp suit my speaker?

[stuee]

Ive tried sending the message below to the seller 3 weeks ago to no reply.
Could someone here answer it for me?
thanks

"
Dear modders_chn,

Hi. I am after something like this for my speaker which im turning into a subwoofer. I will be using the sub out Chanel from my surround sound which is a single Chanel filtered output.

Would this be suitable for my or what could you recommend as its only 1 speaker
Specs:
**broken link removed**

This is already been installed in a large box and just need power now.
Thanks

- johns.stuar
"
**broken link removed**

 

[chemelec]

Well the Amp Might be OK, but does it Include the Power Supply?

As to that Speaker, Not Impressed, I don't see any Detailed Specifications.
200W Means What?
RMS power? Peak Power? or only heaven knows?
It doesn't really look like a High Quality 200 Watt Speaker!

and your Large Cabinet?
Did you Tune it to the "Speakers Parameters", If you actually got any Cabinet Specifications?

 

[ronsimpson]

There is no power supply.

 

[chemelec]

There is no power supply.

It Says it requires +/- 60 VDC.
Doesn't say at What Current.

So you need to get one seperate?

 

[stuee]

Hi, thanks for your input, i tried contacting them at djcity and they said they dont have anymore info on it. grr. i purchased it a couple of years ago now.
I have a torrid transformer i think at home but not sure of voltage / amperage.
The box i made is 60cm wide, 54cm high x 70cm deep. I basically want it as a sub only low frequencies as my yamaha amp has the sub channel out filtered.
I would prefer it using a line out so i can control the frequencies its producing though.
This is just a big ass sub box / table for my mancave. If it blows ill get another one.
If anyone has another suggestion please let me know.

Another thing i was looking at was to use 2 12" car sub speakers. would that work, but i would still need a amp for it.

cheers
Stu

 

[audioguru]

NEVER buy a speaker that does not have any spec's and has a tiny magnet.
Half-decent speakers have detailed spec's and a recommended enclosure design with a graph showing the system frequency response.

The spec's for the amplifier show low distortion up to only 100W into 8 ohms. I could not find spec's for the amplifier on IR's website.

 

[KeepItSimpleStupid]

I did some looking. Sure has a 13 page note on their website and IR has some data there. The IR and Sure specs seem to use a 4 ohm load. The power supply reccomended by Sure is 5A/ Just take I^2*4 and you get 125W. They also say 1 channel driven.

Something is fishy. It's probably a good amp, but someone is selling them by some modified Watts. The standard sets the wattage RMS into 8 ohms and both channels driven. 4 ohms for car stuff. Something always limits the power. I may have not done the calculation above completely right. In any event, the power supply plays a major role. Even so, take 5*0.62*60*2*1.4 is about 250 Wrms. That's the most you can expect out of the amp for BOTH channels using current as the limiting factor.

There is a lot of weirdness in picking the right supply. Don;t ask me how I know,

 

[audioguru]

I did some looking. Sure has a 13 page note on their website and IR has some data there. The IR and Sure specs seem to use a 4 ohm load. The power supply reccomended by Sure is 5A/ Just take I^2*4 and you get 125W. They also say 1 channel driven.

One channel is driven because maybe the amplifier gets too hot at full output when both channels are driven.
A 4 ohm load uses almost double the current so the output power is almost doubled.
If the RMS current in 4 ohms is 5A then the RMS voltage is 5A x 4 ohms= 20V. The peak to peak output voltage is 20V RMS x 2.828= 56.6V. The amplifier output has some voltage loss so the power supply voltage might need to be plus and minus 30VDC or 34VDC.

Something is fishy. It's probably a good amp, but someone is selling them by some modified Watts. The standard sets the wattage RMS into 8 ohms and both channels driven. 4 ohms for car stuff. Something always limits the power. I may have not done the calculation above completely right. In any event, the power supply plays a major role. Even so, take 5*0.62*60*2*1.4 is about 250 Wrms. That's the most you can expect out of the amp for BOTH channels using current as the limiting factor.

The spec's for this one and many other amplifiers has the power measured when the output is clipping like crazy with 10% distortion so the power number is higher than if the amplifier is not clipping.

A plus and minus 60V power supply is used on the datasheet from IR. The amplifier has some voltage loss so its maximum peak-to-peak output might be 110V which is 38.9V RMS. Then its maximum output without clipping is 38.9V squared/8 ohms= 189W.

The amplifier is sold on ebay and is made in China. Quality??

 

[chemelec]

Stuee, If your Cabinet is NOT TUNED to the Speaker Parameters, it is VERY UNLIKELY you will get GOOD BASS.
At Minimum, The Cabinet should be Ported or Tuned with a tube, so the cabinet is Resonant at the Free Air Resonance of the Speaker.

You need a Scope and Frequency Generator to determine the Speaker Free Air Resonance.

 

[audioguru]

I think the cheap speaker will resonate at about 80Hz and sound boomy. It probably will not produce deep bass.

 

[audioguru]

One speaker supplier says the speaker is made by Jensen. It is not listed on Jensen's website but a newer C15 speaker is listed and looks the same with a tiny magnet. It is a 15" guitar speaker so it does not produce deep bass. It resonates at 73Hz (I was close guessing 80Hz) and is rated for 50W or 100W "music power". 200W is peak music power. Its frequency response on an infinite baffle shows a broad peak at 120Hz (boomy sound) and a narrow but strong peak at 1.8kHz (shrill sound).

A sealed box will increase the resonant frequency. It will sound awful with good music but might sound OK playing electric geetar noises.

 

[rumpfy]

Going by the look of the speaker from the photo, it looks like to me that the magnet is far too small to do anything. I would expect the speaker would need 200 watts to make any noise at all and the damping would be woefully inadequate. The speaker would produce a single note at its resonant frequency. Crap speakers like this is why some woffers are known as boom boxes. In short, if the speaker doesnt weigh at least 7 or 8 Kg I would give it a miss.
You did say 'subwoofer'.

 

[audioguru]

Crap speakers like this is why some woffers are known as boom boxes.

I agree that the woofer is a "woffer".