matching effeciencies

[TomatoBangBang]

Good afternoon everybody

If i have a woofer that is 7->15dB less sensitive than my mid and tweeter what are the options for me ?

Because i know i can attenuate the mid and highs but is there a way to increase the "gain" (sorry i don"t know how to say that) of the woofer so i will not lost the benefit of the high effeciency of the other drivers ?


The system planned will be with passive crossover.


At which point (diffrence of dB) a woofer will sound appart from the rest ?

Thanx

[ocool_15]

There is no way to gain efficieny like that.

You can go to multiple woofers.
Use woofer of lower impedence(higher sensitivity)
Or you can bi amp( 2 seperate amps) to provided more power to the woofers.

[TomatoBangBang]

There is no woofer with 110 dB of effeciency, so what are my possibilities ?

I can't use multiples bass drivers

[WithTarragon]

You need to provide a context to your question.

Are you concerned about efficiency because you are using a small amp?

Or are you concerned about efficiency because of the inverse relationship between efficiency and the speaker's distortion?

The efficiency of the speaker will, in effect, also be a function of the cabinet it is in (especially the woofer). Where did you get your efficiency numbers? If they are from the manufacturer take them with a grain of salt. Sometimes, they "add" room gain or measure at a different distance etc.

Again, why are you interested in efficiency?

[djarchow]

The other thing to consider is that once you account for baffle step losses in the XO, your woofer will be probably down 3-6 more db at low frequencies so that is another 3-6 db you will need to pad the mids and tweeters on top of the 7-15 db you mentioned.

However you won't know how much you need to actually pad the mid and tweeter until you actually measure the frequency response of all three drivers on your baffle.

Regards,

Dennis

[Dr. Ram]

Originally posted by djarchow
...until you actually measure the frequency response of all three drivers on your baffle.

...or simulate them using some decent software.

In my experience creating a [simulation] model of the driver using its T/S parameters etc. also often solves the problem pointed out by WithTarragon: that of sensitivity figures not being accurate. These models will tell you the sensitivity you should expect given the set of T/S parameters, and you can easily tell if the manufacturer was being accurate.

The extent to which baffle step makes a difference for you will really depend on your listening environment. Mount the speakers on a wall in a listening room and it will make hardly any difference. Listen to them in your garden and you will find a significant loss. Again, those losses depend on the frequency, the baffle width etc etc. and you can use formulas and software models to quantify all of that fairly well.

-Ram

[infinia]

Originally posted by TomatoBangBang
There is no woofer with 110 dB of effeciency, so what are my possibilities ?

I can't use multiples bass drivers

Have you looked at bandpass enclosures?
You can get some good gain at the expense of woofer bandwidth.
...but for gains you need would be around an octave or less.

This is for pro sound? In HiFi we should speak about sensistivity instead of eff.
cheers

[TomatoBangBang]

Originally posted by WithTarragon
You need to provide a context to your question.

Are you concerned about efficiency because you are using a small amp?

Or are you concerned about efficiency because of the inverse relationship between efficiency and the speaker's distortion?

The efficiency of the speaker will, in effect, also be a function of the cabinet it is in (especially the woofer). Where did you get your efficiency numbers? If they are from the manufacturer take them with a grain of salt. Sometimes, they "add" room gain or measure at a different distance etc.

Again, why are you interested in efficiency?

Thanx WithTarragon for your reply (and thx to ocool_15 too)

Ok i explain the problem

I need to construct a horn speaker that can be used with low set amp

And that can have a small enclosure for the bass

So i had thought about taking a middle sensitive woofer to reduce the size of the enclosure and find a way to match it with compression drivers

It seems to be not possible

--------

I just read on the forum about the isobarical configuration

It can reduce the size of enclosure BUT it makes the effeciency worse of 3dB

So it is not the solution

--------

OR I can biamp as have said ocool_15 and put an amp inside the bass enclosure in isobaric configuration and let the rest of the drivers be powered by SET amp.

-------

What would happen for the headroom if i put 4 bass drivers per channel in isobaric configuration does it resolve the problem ?

[TomatoBangBang]

I just read that there is a possibility to put a step up tranformer in the speaker

Can it work ???

If yes with which result ?

That can be a great solution for me

[TomatoBangBang]

Originally posted by infinia




Have you looked at bandpass enclosures?
You can get some good gain at the expense of woofer bandwidth.
...but for gains you need would be around an octave or less.

This is for pro sound? In HiFi we should speak about sensistivity instead of eff.
cheers

It seems to require some space though, but well why not

Have you presonnaly tested this kind of enclosure ?

For the bandwitch as i don't want to use a mid bass horn ; i am wondering if this is really a possible solution for me

The bandpass solution shorten the bandwithch so ...