NS3 "PC Speakers"

[michiu]

Hi all, I'm putting together something similar to the 4" cube PC Speakers done by Wolf as one of my first projects.

It uses the Aurasound NS3-193-8A in line with a 500uF cap. What I'm struggling to understand is the purpose of the cap. From what I know, its acting as a high pass that has a cutoff frequency of ~40hz.. what is the benefits of that?

[planet10]

Personally i am not a fan of an in-line cap on a sealed box. AFAIK it is to flatten the response of a too-small box. If i was faced with too small a box i'd make it aperiodic.

Since i am averse to electrolytics, the film caps to do 500 uF would be way more expensive than the driver, and take up as much space as the box.

My NS3 were in about a 1.5 litre box, they worked fine.

dave

[michiu]

Originally Posted by planet10

Personally i am not a fan of an in-line cap on a sealed box. AFAIK it is to flatten the response of a too-small box. If i was faced with too small a box i'd make it aperiodic.

Since i am averse to electrolytics, the film caps to do 500 uF would be way more expensive than the driver, and take up as much space as the box.

My NS3 were in about a 1.5 litre box, they worked fine.

dave

Many thanks for the numerous tips you have given me.

The response of your 1.5L NS3 was acceptable without a filter? Would this be an aperiodic or a sealed box that you put them in?

[planet10]

Performance was acceptable. Bass is one thing the NS3 has no lack of (for a 3")

The box is sealed.

dave

[tuxedocivic]

Yup, scrap the cap. Especially if your computer is your source.

[sreten]

Hi,

There is nothing wrong with the principle on an inline capacitor for
sealed. It works well if done properly but its severely not fashionable.

For a FR you should be looking at a capacitor consisting of multiple
parallel types, and I'm not going to suggest values and types, only
to be pointlessly argued with by a bunch of component fascists.

rgds, sreten.

[Melo theory]

haha!
awesome.

(I mean....brilliant)

[tuxedocivic]

Hi Streten, my current two way has 5 caps in it. I'm far from a component fascist. But how does putting a cap in series help this system? It's hooked up to a computer. If he needs the high pass, the computer can do it. If he needs bass boost, the computer can do it. The computer can do anything a cap can.

[sreten]

Hi,

You can model it in the demo version of Basta!.

Here is one implementation explaining the principles :
http://www.humblehomemadehifi.com/do...20Box_copy.pdf

The fairly high Qts NS3 should be ideal for the technique.

Note that the capacitor improves the bass response and
adds some subsonic filtering which is always going to be
useful with such a tiny driver, even with AV fitering.

An interesting option is a single rail power amplifier and making
the speaker capacitor also the amplifier output coupling cap.

rgds, sreten.