High passing a speaker internally?

[Dom500]

Hello
I've been mulling over this idea for a while and wonder if anyone's got any suggestions, or even if it's possible.
Can I modify my Yamaha NS1000 crossover in a semi simple way so that the speaker only sees above 120 hertz?
I've read the Troels Gravesen crossover gets more bass out of them but it's expensive for something you can't reasonably sell on if you don't like it. My speakers have been recapped but to standard values.
I know you can buy inline rca filters but I've read varying reports on them actually working well.

Any suggestions?
Cheers.

 

[Radford Revival]

High passing a speaker with passive components is a bit of a pain as that generally means using a large capacitor of some sort, which in of itself isn't a problem.

The issue is that the woofer suspension / air spring of the speaker looks like an inductance which will resonate with your high pass capacitor, causing an unexpected LF peak right where you didn't want it

(The reason a speaker looks like an inductor at low frequencies is that it's storing energy in a mechanical spring instead of a magnetic field, the combination of motion and back EMF simulate an inductor. Alternatively you can think of the capacitor as a mass which you've added to the spring which is the speaker!)

 

[Dom500]

That's an excellent explanation thank you!

 

[James]

Can I modify my Yamaha NS1000 crossover in a semi simple way so that the speaker only sees above 120 hertz?
I've read the Troels Gravesen crossover gets more bass out of them but it's expensive for something you can't reasonably sell on if you don't like it. My speakers have been recapped but to standard values.

What are you trying to achieve? If you're planning on using a sub-woofer, then you can either use the sub's high pass or insert an active filter between your amp and NS-1000s.

I happen to have installed the TG crossover in my NS-1000Ms, and I can tell you with absolute confidence they are transformed. You can read about my experience here.

 

[martin clark]

(The reason a speaker looks like an inductor at low frequencies is that it's storing energy in a mechanical spring instead of a magnetic field, the combination of motion and back EMF simulate an inductor. Alternatively you can think of the capacitor as a mass which you've added to the spring which is the speaker!)

Excellent simple explanation!

Small clarification if I may - it's the inductance that acts exactly like Mass, the capacitor is the 'spring'. There are formal equivalences, too : )

Sidebar:
NB this raises a great side-point - sometimes using cap-coupling , can be used to advantage - not for the NS1000, but the Quad 303 & ESL57 are a good example... from our own @Jim Audiomisc :

Interaction of QUAD 57 and 303

www.audiomisc.co.uk

 

[Dom500]

What are you trying to achieve? If you're planning on using a sub-woofer, then you can either use the sub's high pass or insert an active filter between your amp and NS-1000s.

I happen to have installed the TG crossover in my NS-1000Ms, and I can tell you with absolute confidence they are transformed. You can read about my experience here.

Hi James.
I'm trying to get better bass out of my NS1000 but keep my 20 watt valve amp. I've previously used solid state with them and been slightly happier but they've never had really juicy bouncy bass like I've had out some previous speakers.
I'd definitely rather get the speakers to do this. How much £ does the Troels kit cost in the UK and would this give me what I'm after in your opinion?
Cheers!

 

[James]

Hi James.
I'm trying to get better bass out of my NS1000 but keep my 20 watt valve amp. I've previously used solid state with them and been slightly happier but they've never had really juicy bouncy bass like I've had out some previous speakers.
I'd definitely rather get the speakers to do this. How much £ does the Troels kit cost in the UK and would this give me what I'm after in your opinion?
Cheers!

I have never used a valve power amp, and so won't be in an position to comment on whether the TG upgrade will meet your expectations of "juicy bouncy bass". The Yamahas don't really do juicy, but there is definitely bounce - which was improved with the new crossovers. If you write to Troels with your question, and stating what amp you are using, he would be in a better position to answer your questions.

But, FWIW, my modified NS-1000Ms actually sounds better with a 30W class A amp than 125W class AB. So, I cannot see why - in theory - a 20W valve amp won't be any good.

 

[Radford Revival]

Excellent simple explanation!

Small clarification if I may - it's the inductance that acts exactly like Mass, the capacitor is the 'spring'. There are formal equivalences, too : )

Hmm, does the equivalence not depend on the specific system though? Here is my reasoning:

Imagine you have a free moving voice coil with mass in an infinitely long magnetic circuit, like a woofer with infinite x-max and no suspension. assuming no Le (superconducting shorting ring!) and no Re (again, superconductors).

If you apply a voltage, the coil will accelerate until the back EMF equals that of the driving EMF. If you disconnect this free floating voice coil it will continue indefinitely at that velocity, producing the voltage you "charged" it with, much like a capacitor. It would counter changes in voltage with changes in current

Likewise with a spring that simply applied a restoring force according to distance attached to a massless voice coil, the spring would counter changes in current by generating an EMF as the spring would compress/decompress, and move in the field. If you interrupted the current, the massless voicecoil would return to its rest position at infinite speed, producing an infinite voltage spike, just like a theoretical inductor would