computer speakers

[ren_zokuken01]

i've been wanting to buy new high quality computer speakers for some time now, but as cheap as i am, i'm unwilling to go further than $25. purchasing used ones are a no-no for now.

so i was wondering if it is a practical option to actually just swap the amplifier inside my old speaker enclosure with a higher quality one that i could get for a very low price or i could assemble myself??

 

[Hero999]

The amplifier is not the only problem, the cheap speaker drivers and enclosures make it sound poor.

You might be able to buy some great sounding speakers for that, the trouble is cheap speakers don't come with any real frequency response specifications and have a grossly exaggerated power specification.

Why not build your own?

The trouble is you've set your budget so low, there's no chance of getting decent bass response which requires a large expensive woofer.

You need to choose drivers which have a proper datasheet with a frequency response curve given, which also needs to be as flat as possible.

For example, my local supplier sells a 4W RMS (10W peak) speaker with a flat frequency response from 200Hz to 20kHz for

 

[audioguru2]

The frequency response curve of the tiny speaker has an error when it is enlarged.

It has a resonant frequency of 330Hz when in free air. Then it will have a response that is flat down to 330hz when it is mounted on a huge infinite baffle and it might reduce frequencies below 660Hz when mounted in an enclosure.
Its output level is very low.

I agree that it will not produce bass frequencies.

View attachment 41066

 

[Hero999]

Where's the error?

That graph looks pretty standard to me. The one you posted is fuzzy because it's ripped from the PDF, is low resolution and has probably gone though JPG compression, the one on the Visaton website (posted above) is more clear.

RS Components seem to be a bit cheaper for speakers, for a penny more they sell a twin cone speaker which is more sensitive, has better bass response (although still not good enough) and the treble is just as good.

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=4635818#header

The Visaton website gives more information:
http://www.visaton.com/en/chassis_zubehoer/breitband/fr10hm_4.html

Do you know of any other reasonable speaker brands? My local suppliers sell Visaton which seem good, although I've not tested them myself but some of the speakers inside my TV and radios are probably Visaton.

Oh, I've just found a cheap wooker by PRO SIGNAL which has a datasheet and frequency response graph, although  know that the peformance depends on the enclosure, which I admit I don't know much about.
http://www.farnell.com/datasheets/310178.pdf
http://uk.farnell.com/pro-signal/ls00430/woofer-polyprop-cone-8ohm-8/dp/3708536

 

[audioguru2]

Hi Alun (Hero),
The spec for the tiny woofer states a resonant frequency of 330Hz which is shown in the non-enlarged graph on Visaton and Rapid's sites. I posted it.
But when you click on it the larger PDF graph that you posted it shows a resonance of about 270Hz which is wrong.

The cheap 8" woofer has a low output level. It has a foam surround that will rot away in 10 or 15 years.

 

[ren_zokuken01]

gee, didn't expect great replies in just a short time...

i've always assumed that the frequency response was mostly an amplifier issue, not speaker quality... guess that only shows what i know about this stuff, huh?

well, i'll do more digging on the subject...

 

[Hero999]

No, frequency response is entirely down to the speakers and even the enclosures, modern amplifiers go well below 20Hz to well above 20kHz.

Cheap and good sound quality, especially decent bass response are incomparable requirements.