Kenwood speaker

[Kamranbites]

I have a Kenwood speaker. when i opened it i just saw the audio wires we're directly connected to speaker (woofer) no corssover was installed in it . Just a capasitor attached to a Twitter

Is it ok or should I install a crossover to it 

[H713]

It has a filter (crossover), it's just of the crudest type. The inductance of the woofer leads to a natural rolloff in frequency response, probably in the 800 - 7000 Hz range, depending on the driver. The cap, combined with the impedance of the tweeter, creates a high-pass filter. This is important, because a typical dome tweeter isn't going to last long with 50 watts of bass energy pumped into it.

Is this optimal? Almost certainly not. I've seen precious few woofers that can run with just their natural rolloff. Most have cone breakup issues in the HF range that necessitate more aggressive filtering. Metal cone drivers are notorious for this. The tweeter, unless it's got a really high crossover frequency or is very beastly, will be operating in a fairly non-linear area due to the shallow slopes. If it's crossed really high, then there's going to be a nasty directivity mismatch between it and the tweeter.

 

But... should you mess with it? If you're asking that question, the answer is probably not. To accomplish this, you're going to need a decent measurement microphone - the $50 one from Dayton Audio or Behringer is the minimum viable IMO. You'll need a decent room to do it, preferably one that isn't an acoustic disaster - you can compensate for some of this in software, but don't expect to measure speakers in your bathroom. A big open parking lot isn't a bad choice.

 

If you're going to do active, then you need some sort of DSP box to play with filters. Do NOT try to build this yourself - trying to learn speaker design and digital signal processing at the same time is a recipe for failure. I use both an XTA active crossover and a Soundweb London box for this testing. You'll also need a couple of good amplifier channels that behave in a predictable manner - I use an MC2 MC450 for this, but anything with sufficient power, reasonable distortion and a well-designed protection circuit will do fine.

 

If you're doing passive crossovers, then I would really want to have a good LCR meter (make sure it can measure inductor Q). A low frequency network analyzer is really nice to have as well, but is not absolutely necessary. You'll DEFINITELY want some simulation software unless you really enjoy manipulating transfer functions by hand. Xsim is free and bone simple, Vituixcad is also popular.

 

So, the point I'm making is this: Unless you have the tools and engineering background, or a strong desire to learn, you're probably best to leave it alone. Just slapping a random off-the-shelf crossover in there will most likely make things worse rather than better. Loudspeaker crossovers are something that needs to be designed for those specific drivers in that specific enclosure. 

 

Generally speaking, loudspeaker design is pretty physics-heavy. It's not microwave engineering, but it's still tricky.

[Kamranbites]

21 hours ago, H713 said:

It has a filter (crossover), it's just of the crudest type. The inductance of the woofer leads to a natural rolloff in frequency response, probably in the 800 - 7000 Hz range, depending on the driver. The cap, combined with the impedance of the tweeter, creates a high-pass filter. This is important, because a typical dome tweeter isn't going to last long with 50 watts of bass energy pumped into it.

Is this optimal? Almost certainly not. I've seen precious few woofers that can run with just their natural rolloff. Most have cone breakup issues in the HF range that necessitate more aggressive filtering. Metal cone drivers are notorious for this. The tweeter, unless it's got a really high crossover frequency or is very beastly, will be operating in a fairly non-linear area due to the shallow slopes. If it's crossed really high, then there's going to be a nasty directivity mismatch between it and the tweeter.

 

But... should you mess with it? If you're asking that question, the answer is probably not. To accomplish this, you're going to need a decent measurement microphone - the $50 one from Dayton Audio or Behringer is the minimum viable IMO. You'll need a decent room to do it, preferably one that isn't an acoustic disaster - you can compensate for some of this in software, but don't expect to measure speakers in your bathroom. A big open parking lot isn't a bad choice.

 

If you're going to do active, then you need some sort of DSP box to play with filters. Do NOT try to build this yourself - trying to learn speaker design and digital signal processing at the same time is a recipe for failure. I use both an XTA active crossover and a Soundweb London box for this testing. You'll also need a couple of good amplifier channels that behave in a predictable manner - I use an MC2 MC450 for this, but anything with sufficient power, reasonable distortion and a well-designed protection circuit will do fine.

 

If you're doing passive crossovers, then I would really want to have a good LCR meter (make sure it can measure inductor Q). A low frequency network analyzer is really nice to have as well, but is not absolutely necessary. You'll DEFINITELY want some simulation software unless you really enjoy manipulating transfer functions by hand. Xsim is free and bone simple, Vituixcad is also popular.

 

So, the point I'm making is this: Unless you have the tools and engineering background, or a strong desire to learn, you're probably best to leave it alone. Just slapping a random off-the-shelf crossover in there will most likely make things worse rather than better. Loudspeaker crossovers are something that needs to be designed for those specific drivers in that specific enclosure. 

 

Generally speaking, loudspeaker design is pretty physics-heavy. It's not microwave engineering, but it's still tricky.

So there is no need of messing around with cross over.But there should be some protection to the woofer it is just directly connected to my amplifier i have seen people removing protection boards from there speakers and blowing them up it will be same in my case if i increase my volume any way i can add some kind of 40w Protector or some kind or inductor ect 

[H713]

Crossovers generally provide NO protection to a woofer. They are just a filter. In theory, it would be nice to have some very low frequency filtering - that speaker probably doesn't do much below 40 Hz anyway, so there's no reason to let stuff down in the 20 Hz region drive it harder than needed. In practice, building a passive filter of this sort requires a really, really big passive components that are rated for very high power levels. You're going to spend more money on passive components than the speakers are worth.

 

If you're really worried about it, put a fuse inline, or exercise self-control with volume levels. Don't do something stupid with varistors or PTCs - all you're going to do is add a bunch of distortion. 

 

Most passive speakers have no protection in them. The woofers on most passive speakers (even pro speakers) can be easily destroyed with excessive low-frequency energy (DC from an amplifier being the biggest offender here), and the tweeters can be destroyed by excessive HF energy (ultrasonic oscillation from an amplifier can do this). We live with these vulnerabilities, because protecting against them generally isn't worth it.

[Kamranbites]

5 hours ago, H713 said:

Crossovers generally provide NO protection to a woofer. They are just a filter. In theory, it would be nice to have some very low frequency filtering - that speaker probably doesn't do much below 40 Hz anyway, so there's no reason to let stuff down in the 20 Hz region drive it harder than needed. In practice, building a passive filter of this sort requires a really, really big passive components that are rated for very high power levels. You're going to spend more money on passive components than the speakers are worth.

 

If you're really worried about it, put a fuse inline, or exercise self-control with volume levels. Don't do something stupid with varistors or PTCs - all you're going to do is add a bunch of distortion. 

 

Most passive speakers have no protection in them. The woofers on most passive speakers (even pro speakers) can be easily destroyed with excessive low-frequency energy (DC from an amplifier being the biggest offender here), and the tweeters can be destroyed by excessive HF energy (ultrasonic oscillation from an amplifier can do this). We live with these vulnerabilities, because protecting against them generally isn't worth it.

Oh thanks for info. I am using nobsound ns-20g with my speakers amplifier is 200w. so i am connecting 4 speakers to it. So that I can  use the power effectively. 2 are aiwa and two are Kenwood so should I connect them in series or parallel 

My amp rating is from 4-8 ohms 

Series gives me 12 ohms and parallel gives me 3 ohms