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Guys, I need information on one of my friends request.

He wants to run computer speakers [ 2 rectangle boxes of yesteryears ] running on 240V, using the output from the cigaratte lighter point .

First of all, is it possible ?

Next, if yes, Do we need a adpater ? and if yes, where can we source the same in Bangalore.

Appreciate your kind attention and help

Quote:

Originally Posted by akbaree (Post 1257027)

They are presently crossed over at 63 Hz. The Frequency Response says 43Hz to 25K Hz (because it includes the tweeter frequency as well). What's the point in declaring Frequency Reponse starting at 43 Hz when Resonant Frequency is at 86 Hz. I am not aware of what Resonant Frequency means. Please elaborate.

This brings me to another question. Can they be used as a midrange drivers in a 3 way setup? Any pros and cons?

@navin: please throw some light on this.

Quote:

This parameter is the free-air resonant frequency of a speaker. Simply stated, it is the point at which the weight of the moving parts of the speaker becomes balanced with the force of the speaker suspension when in motion. If you've ever seen a piece of string start humming uncontrollably in the wind, you have seen the effect of reaching a resonant frequency. It is important to know this information so that you can prevent your enclosure from 'ringing'. With a loudspeaker, the mass of the moving parts, and the stiffness of the suspension (surround and spider) are the key elements that affect the resonant frequency. As a general rule of thumb, a lower Fs indicates a woofer that would be better for low-frequency reproduction than a woofer with a higher Fs. This is not always the case though, because other parameters affect the ultimate performance as well.

Eminence - The Art and Science of Sound

the speaker will continue to produce sound below its free air resonance frequency as well, just that it will become lower depending on the Q ratio. and the free air resonance is exactly that , FREE air resonance. once installed , other things come into play, which will push the resonance frequency, usually lower.

Either way, dont give those mid basses so much LF content. cross them over higher ( 80~100 Hz) , and let the subs handle the lows

Quote:

Can they be used as a midrange drivers in a 3 way setup? Any pros and cons?

probably, if you plan on using 8 inchers as the woofers or so. but if you gave a sub, you are already running a 3 way setup :p

Quote:

Originally Posted by akbaree (Post 1257027)

What's the point in declaring Frequency Reponse starting at 43 Hz when Resonant Frequency is at 86 Hz.
If they cannot be pushed beyond 100 Hz, I would only hesitantly call them mid bass drivers. This brings me to another question. Can they be used as a midrange drivers in a 3 way setup? Any pros and cons?

43Hz might be -10db down. No way they gonna like making 43Hz. As midbass drivers they are ok if limited to about 3K. WHy becasue Bl is only about 7TM and Mms is over 10gms. So use them between 100Hz and 3kHz.

Quote:

Originally Posted by greenhorn (Post 1259650)

probably, if you plan on using 8 inchers as the woofers or so. but if you gave a sub, you are already running a 3 way setup :p

agree:. But I meant 3 way front stage plus the sub.

Quote:

Originally Posted by greenhorn (Post 1259650)

the speaker will continue to produce sound below its free air resonance frequency as well, just that it will become lower depending on the Q ratio. and the free air resonance is exactly that , FREE air resonance.

Either way, dont give those mid basses so much LF content. cross them over higher ( 80~100 Hz) , and let the subs handle the lows

Quote:

Originally Posted by navin (Post 1259701)

Thanks so much. But I am still not sure if I get this completely. I now understand what is Free air resonance but I don't understand the effect of crossing them lower than the Resonant Frequency.

So if I am crossing them below the Fs, they...

will produce the music but at lower decibels and will not be audible?
will it harm the driver?
will it cause distortions in the legitimate frequency range for the driver?

Quote:

Originally Posted by navin (Post 1259701)

As midbass drivers they are ok if limited to about 3K. WHy becasue Bl is only about 7TM and Mms is over 10gms. So use them between 100Hz and 3kHz.

Now I know, why the Crossover Frequency between Mid Bass and Tweeter is at 2600 Hz for this component set.

Quote:

Originally Posted by akbaree (Post 1261101)

So if I am crossing them below the Fs, they...

will produce the music but at lower decibels and will not be audible?
will it harm the driver?
will it cause distortions in the legitimate frequency range for the driver?

Yes it will produce music that may or may not be audible depending on cabin gain/loss. It wont harm the driver. Remember you are not loading the driver by putting it in a TL, bass reflex or band pass box. However reducing the low freq. load on the driver will make it sound better in the midbass.

ideally you dont want them working at resonance, since they will be quite loose and boomy and not controlled in that band, thats why we recommend crossing them HIGHER than the resonant frequency so that those frequencies dont get to the speaker

Quote:

will produce the music but at lower decibels and will not be audible?

no, but at FS and thereabouts , it will be louder, much more so than elsewhere in the rest of the frequency band, and this may affect the linearity

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will it harm the driver?

not much

Quote:

will it cause distortions in the legitimate frequency range for the driver?

yes. the linearity of the frequency response might be compromised