Sub woofer

[Jean]

Hi everyone

I have several doubts regarding subwoofer and its amplifier

-1- What is the basic difference(in construction,working and
performance) between a subwoofer and an ordinary woofer ?

-2- When was sub woofer first introduced ?(And who introduced it ?)

-3- How can I detect a distorted output from a subwoofer ?

-4- What are the specifications of the box on which the sub is to be
mounted ?

-5- Is the shape of the box significant ? Or is that the volume of the
box that matter ?

-6- I have bought a subwoofer named 'DAINTY'.On the sub the following
are written...8 Ohm,130W RMS,260W MAX .Have you ever heard a company
like that ? Or is it a local make ?

-7- Will an amplifier constructed with a TDA 7294 work ?

-8-What should be the power rating (I expect VA,RMS output voltage,RMS
output current) of the transformer to be used for maximum power output
?

-8- What are the rating of the rectifier diodes and the filter
capacitor to be used for the dual DC power supply ?

Thanks in advance

Jean

 

[gothika]

On 17 Jan 2004 21:34:25 -0800, alertjean@rediffmail.com (Jean) wrote:
Sub woofer is something of a misonomer these days.
Sub amps are generally no different that regular amps.
some of the better high end sub amps are designed to to do a little
better job of delivering low freq signals, other than that no
difference and any good class A amp will do the job if it's bottom end
will carry the desired lower cycles.
Most so called "sub woofer" systems don't actually get into the sub
range and generally have a clip point around 30-35 Hz. They just tend
to boost the low end of the standard hifi to near equal volume levels
of the mid and highs.
This does result in better bass response, but we used to get the same
out of good audiophile systems in the old days.(I used a Macintosh
class A tube amp into Klipshorns and got better bass response than
todays run of the mill sub systems.
That said you can get real sub performance today, say that in the
18-24 Hz range if you take care in building the system yourself.(Or
pay for it from an audiophile shop.)
You have to make sure that your source material actually carries the
low freqs you want to boost. Better CD's and most DVD audio/video
material usually carries some decent low Freqs.
Your preamp/sound card have to have the range to pass it and the power
amp has to have the ability to carry it.(Some amps have cut-off or
notch filters to stop low freq signals to avoid distorting audible
signals. i.e. these amps can't handle the low freq due to design
limitations, usually put in them to avoid blowing out todays marginal
performance speakers.)
Make sure the amp you choose has a low freq cutt-off near 0Hz.
(I have an old class H amp that I sometime use for that, it's working
range is 0-35,000 Hz)
As for the driver/s it's best to keep to a sealed enclosure,
especially if you plan to build yourself. Ported or folded enclosures
tend to be very tricky to build for anyone without a audio test lab at
their disposal.
Sealed boxes tend to have a "tighter, punchier" sound as well,
something desirable when listening to AV sources.(Tend to be best for
video and 5.1 sound.)
There are alot of good woofers on the market, my recommendation is to
get a 12-15 inch woofer/s in a sealed box of the right size. Makes for
an easier build/setup and you can always pack or remove stuffing in
the box to get the right sound for your ear.
Stay away from square boxes, they spell doom for low end response.
Go rectangular and make sure you use some really thick mdf(at least 1
inch) or good quality 8-10 ply oak plywood(Birch is good also but very
costly.) of at least an inch thickness.(I use 1-1/4 inch 10 ply
acoustic plywood, but that has to be special ordered and most consider
it overkill.)

As for your question about the "Dainty" ,never heard of it, but I'm
mostly old school. Perhaps someone else here can help you on that as
well as your questions on the rectifiers diodes on the dual power
supply.(Not sure what type of system your trying to build. If you give
me more details on the basic design I could help. i.e. will it be
active crossover system or passive equal. etc??)
Is the sub box you refer to internally powered etc???

Hi everyone

I have several doubts regarding subwoofer and its amplifier

-1- What is the basic difference(in construction,working and
performance) between a subwoofer and an ordinary woofer ?

-2- When was sub woofer first introduced ?(And who introduced it ?)

-3- How can I detect a distorted output from a subwoofer ?

-4- What are the specifications of the box on which the sub is to be
mounted ?

-5- Is the shape of the box significant ? Or is that the volume of the
box that matter ?

-6- I have bought a subwoofer named 'DAINTY'.On the sub the following
are written...8 Ohm,130W RMS,260W MAX .Have you ever heard a company
like that ? Or is it a local make ?

-7- Will an amplifier constructed with a TDA 7294 work ?

-8-What should be the power rating (I expect VA,RMS output voltage,RMS
output current) of the transformer to be used for maximum power output
?

-8- What are the rating of the rectifier diodes and the filter
capacitor to be used for the dual DC power supply ?

Thanks in advance

Jean