equalizers, crossovers, and bass reconstructors??

[miker 5,000+ posts]

There are so many options for these? What exactly are they?

and for cross overs, you have what you would pass the signal from your amp through to your speaker like what you get in a component set, and then there are others? with RCA inputs and outputs.

Click to read more...

 

[helotaxi 5,000+ posts]

Crossovers- These are used to divide or filter frequencies between drivers so, for example the woofers get the bass, the mids the midrange and the tweeters the treble. two main types, active and passive. Active has its own power supply and requires a power and ground connection. These pretty much always wire in before the amp(s) in the RCA signal path. Passive require no external power and use capacitors, inductors and resistors to filter the frequencies. These are the type that come with component sets but there are some that wire inline before the amp.

Equalizers- again can be passive or active. Active is by far the most common and it wires in before the amp. These boost or cut certain frequencies, but they pass all frequencies through.

 

[helotaxi 5,000+ posts]

Oh and Bass Reconstruction processors are actually more closely related to synthesizers than filters. They actually add in frequencies that are not in the signal using frequencies that are in the signal as a basis.

 

[emilimo701 10+ year member]

i have a sort of related question...

Right now I have a sub (polk SR12 dvc) in a sealed box. I want my low-lows to be louder because of the slope that comes with using a sealed box. I find that the bass boost on my amp at 45hz is a little too high, and that because of the nature of the roll-off, a bass boost around 30hz would be a little more appropriate. Specifically, I want a flatter response down to about 28hz not for use while driving but for tailgating. I realize that the easiest solution is just to put it in a ported box tuned low, but would any type of EQ (that doesn't cost more than $100ish) be an adequate solution?

Would using a high pass crossover with a shallow slope (6db/octave) work? I realize this might make the sub more "power-hungry" but I have some headroom on my amp

 

[helotaxi 5,000+ posts]

All you will do by adding bass boost (nothing more than a single band of EQ) is cause the amp to clip when you turn up the volume. You're asking for something that the sub can't provide in a sealed box. The only thing that manipulation of the crossover can really gain for you is an overall higher output at higher frequencies. Not sure what you would want with a high pass crossover on the sub in a sealed box...

 

[miker 5,000+ posts]

Crossovers- These are used to divide or filter frequencies between drivers so, for example the woofers get the bass, the mids the midrange and the tweeters the treble. two main types, active and passive. Active has its own power supply and requires a power and ground connection. These pretty much always wire in before the amp(s) in the RCA signal path. Passive require no external power and use capacitors, inductors and resistors to filter the frequencies. These are the type that come with component sets but there are some that wire inline before the amp.

Equalizers- again can be passive or active. Active is by far the most common and it wires in before the amp. These boost or cut certain frequencies, but they pass all frequencies through.

Thank you, that was exactly what I was looking for.

 

[cablguy184 10+ year member]

Good post to read ...

 

[emilimo701 10+ year member]

I meant low pass sorry.

Like I said I have some headroom in my amp. What I'm asking is as long as it doesn't start to clip (obviously I don't want that) I'm wondering if a low bass boost could flatten out the response, even at the expense of output

 

[Bumpin' Goalie 10+ year member]

I meant low pass sorry.
Like I said I have some headroom in my amp. What I'm asking is as long as it doesn't start to clip (obviously I don't want that) I'm wondering if a low bass boost could flatten out the response, even at the expense of output

I think he is wondering if adding some sort of EQ would help him get a flatter response. Basically, increasing 25-40hz and reducing 40+ to the point of "flat". If I understand correctly.

The firm variable will be his driver, power, and enclosure. The only changing variable being signals.

 

[helotaxi 5,000+ posts]

I know what he's asking. The issue becomes the capability of the driver provided that the amp is kept from clipping. Excursion requirements become exponential to maintain the same relative output as you lower the frequency. Assuming unlimited power, the sub is still going to run out of travel before you get what you're looking for. There's a reason that large room subs are almost always ported.

 

[emilimo701 10+ year member]

I know what he's asking. The issue becomes the capability of the driver provided that the amp is kept from clipping. Excursion requirements become exponential to maintain the same relative output as you lower the frequency. Assuming unlimited power, the sub is still going to run out of travel before you get what you're looking for. There's a reason that large room subs are almost always ported.

and that reason is?

 

[helotaxi 5,000+ posts]

A sealed driver cannot match the low frequency output of a ported one. Sealed boxes can be used to get fairly low in a car because of the cabin gain from the small listening space. As you increase the size of the room the cabin gain decreases until you're effectively in free air. At that point you're getting nothing from cabin gain and the sub system has to produce the desired frequency response all on its own. Most all sealed subs begin to roll off in the mid 50 hz range and have 3dB down point in the mid to high 40s if not higher. That puts them about 9dB down in the mid 20s where a low tuned ported enclosure is only 3dB down. That's a 6 dB difference or the same as running 4x the number of subs or 4x the power or 2x the subs and 2x the power.

 

[emilimo701 10+ year member]

yes I understand, but that doesn't answer my question.

Theoretically it IS possible to EQ a subwoofer flat down to a certain frequency

But why wouldn't this be reasonable? Let me take a crack at it: because it's in a sealed box, it would take so much extra power at the lowest frequencies that the thermal limits of the subwoofer will be reached before output is significant enough to render it worthwhile?

 

[emilimo701 10+ year member]

for example... getting this... setting center frequency to 30-35hz, then fine tuning the bandwidth by ear/test tones

 

[emilimo701 10+ year member]

http://www.sonicelectronix.com/item_18562_Hifonics+Maxxsonics+MX-3.html

 

[helotaxi 5,000+ posts]

Yes, you could in theory EQ it to play relatively flat down to a certain frequency HOWEVER you would have to do this by reducing the level of the upper frequencies to compensate for the fact that excursion is your limiting factor at lower freqs. Efficiency decreases with frequency in a sealed box simply because the motor runs out of BL and the sub runs out of Xmech before you get output equal to that of the driver above F3.