[bblost]

Is there anything like a fixed life for speakers.
Do they need to be replaced every few years, or do they go on and on.

How can we know if the speakers are dying?

[greenhorn]

nope, speakers can last pretty long. the things to watch out for are foam surrounds and paper cones which can disintegrate if the area is damp. I've got some speakers in my house which are older than me, and still work perfectly. The environment in a car might be more hostile, but no, they shouldnt need to be replaced regularly

[navin]

Originally Posted by greenh0rn

Hi Navin, this is interesting stuff. Sorry for the noobish thought, but i didn't know response curves could be different for on-axis and off-axis hearing! :-) Why is it so exactly?

see page 2 of this pdf
http://www.scan-speak.dk/datasheet/pdf/d2905_930000.pdf

the ring radiators measure better but even they have off axis roll off.
http://www.scan-speak.dk/datasheet/pdf/r2904_700000.pdf

It is simple physics as the frequency gets higher the diameter of the dome becomes a factor and can not be considered a simple piston. designers can tweak this roll off making it smooth and controlled (which has been found to be more preferable to an extended response that rolls of very fast and ragged) using wave guides (SS 9900, OW1, etc..) but the basic laws still apply. Ribbon tweeters (G2Si, Raven, etc..) are better off axis but they are fragile. Also a flat off axis respose does not guarntee a nice sounding tweeter.

Originally Posted by bblost

Is there anything like a fixed life for speakers.

Most modern speakers will last 10 years or more. Play them atleast once a week. I once left a set of rather expensive speakers from ScanSpeak un used for 4 years and they died. The VC OCed becuase of collected moisture in Mumbai (think humid).

[greenhorn]

are edge driven domes better than W domes? It seems my hertz dieci looks like a W dome, and the JBL GTO is edge driven one. how do they compare.

Any idea what the other tweeter radiators in the budget component space are like ?

[navin]

Originally Posted by greenhorn

are edge driven domes better than W domes?

Edge driven domes have become more common nowadays. They offer higher power handling and a more pistonic movement of the dome as long as the dome matieral does not ring or flex.

[The Venom]

Hi,where can i find good custom made bandpass maker in delhi???

[DerAlte]

@The_Venom, the issue is a good custom bandpass box design, not maker. Any decent carpenter can make the box if there is a good design. You just have to make sure that the joints are done well and sealed properly.
* Why do you want a bandpass box, instead of conventional BR/ported?
* Which subwoofer do you want to use?

[The Venom]

I thought that bandpass box will produce good bass......i want to use pioneer 307dvc subwoofer.....can u give me any design that i show to the Carpenter which will be easy for him as well!!!

[jaibir]

Originally Posted by jaibir

I've been tweaking around the system for the last couple of weeks with the help of an audiophile friend. The first thing he suggested I get done was some damping for the front doors. Got that last weekend from FM drive. Made a world of difference to their sound. He also tweaked the amp settings and HU settings to bring out the best in the existing speakers. However, the bass on the rears is still too lose. Will try tweaking with the way the rears are installed (possibly some fiddling with the MDF tray) to see if that help make the bass tighter. I'll also be borrowing his sub to see if that suits my needs better.

Any suggestions on possibly tweaks on the rears from the Gurus?

Got the boominess solved. Figured there is nothing wrong with the speakers, but the way they are installed, along with the kick from the amp meant the base would be lose if they were fed the really low frequencies. Solved it by turning on the HPF for the rears. The overall bass is a bit weak now, but planning to add a sub anyway so thats not a problem. Otherwise the speakers sound great. Good enough that I decided to get a separate amp for the sub and keep these on the 1004

[The Venom]

Hi,where can i find good custom made bandpass maker in delhi???

[navin]

Der Alte has answered your question in post #9469.

[arpandiv]

Ok this is a rather weird question and if the gurus find it silly please bear with me.
I am attaching below a pic of a Class AB amp, it is rated at 750W@1ohm.
Looking at the internals can you tell me if the amp is good/bad ?
Ps: brand name left behind on purpose.

[Sam Kapasi]

Originally Posted by arpandiv

if the gurus find it silly please bear with me.
I am attaching below a pic of a Class AB amp, it is rated at 750W@1ohm.

You are right Doggdigga, it is silly(though I'm no guru). What is the rating of the amplifier at 4ohms? Give more specifications.

And next time take a knife, slice open a man's abdomen and ask people to look at his guts and guess if he has a good nature, lol.

[arpandiv]

Originally Posted by Sam Kapasi

And next time take a knife, slice open a man's abdomen and ask people to look at his guts and guess if he has a good nature, lol.

Thats how dumb my Q was ?
Will get the specs and ask.

[DerAlte]

Originally Posted by The Venom

...i want to use pioneer 307dvc subwoofer...

I did a bit of research and found the T-S parameters for the Pio TS-W307D2 sub, and also got the bandpass box calculations at carstereo.

Sorry, I didn't have time to take it beyond this, so you need to take it forward:
* I have attached the box volume calculations in a spreadsheet. There are in fact 2 calculations - one with S=0.7, and another with S=0.6
* Vr is the 'rear' sealed box volume, Vf is the volume of the 'front' part where the port is
* The volumes are given both in cft and litres, so depending on what you are comfortable with, you can calculate the box inside dimensions. You just have to remember that the depth and height are constrained by the sub baffle (mounting plate), which means they have to be >13" inside the box for your sub to fit
* Calculate the dimensions of the port based on the 'front' part frequency Fb (the port could be round/pipe, or even slot type the way @chirag_bir has)
* I read somewhere that it is recommended that the sub should actually be mounted in the 'front' part ("inverted mounting") to promote better cooling of the coil

Now, my dear friend, you have to scour the web for bandpass box mechanical design (Google it, there are plenty), show pictures to your carpenter, and give him the inside dimensions - he will figure out the rest. Just ensure that all joints are made with good dose of Fevicol and screws. Also, you could think of jazzing the whole thing up by making the front side thick perspex and mounting some flashing lights inside.

All the best!