Starting my first project.

[sachi]

Hello all,

i have been a mute spectator and been reading the posts by others for the most part of my membership in this forum.
i decided to finally go ahead and build (or Replace) my first speakers.
I plan to build these speakers as an experiment to test whether i have the inclination and the knowledge to build my own speakers. so, i don't mind bombing out on my first try(obviously i'd be diappointed if that happened). But, i plan to make this a hobby and gain knowledge from the experience and continue to build more.

OK, here are the drivers that i have bought.

midrange-
http://www.partsexpress.com/pe/showd...number=299-492
tweeter-
http://www.partsexpress.com/pe/showd...number=264-526
LF Driver-
http://www.partsexpress.com/pe/showd...number=295-315

.
i know that for my first project a 3-way may be too much work but i don't mind cause from June 4th onwards i am pretty much free for 3 whole months. with the help of this forum i'm confident that i will be able to suceed in getting decent levels of SQ.

here is the problem.
i presently have a pair of old(30 years old) 3-way 4 speaker system sealed monitors. the cabinet is made of teak and filled with glass wool.

as i see it i have 3 possibilites.
1> Replace the existing drivers with the new ones that i have bought and concentrate all effort on designign a new crossover for the 3 way and keep it sealed.
.
2>ditto,except make it a vented enclosure.

3>design and build a complete speaker system from the ground up ,including the enclosure and decide as to sealed or ported along the way.

the dimensions of the old speakers is 20'x9'x11.5'(LxDxW).
The speakers are shown in the picture that i have attached. they are heavier than the wharfedale diamonds that are next to them.
Looking forward to ur views.
Cheers,
Sachi

p.s am having the drivers flown in from US and will have them by the 1st week of June.

[Nappylady]

You can calculate the internal volume of your old cabinets and use a simulation program to find out what the response will look like, but really, it's better to build new cabs than to re-use existing ones and match them to drivers.

Either way, you will need to design your own crossover for your new drivers (good choices, BTW) and that can be really tough.

Madisound has a system whereby you pay them something like $50 and they design the crossover for you, using their special simulation software. Then all you have to do is actually assemble the box and crossover.

[Vivek]

Sachi, which are those tower speakers?

[sachi]

Hey Nappy,
the volume of the enclosure is about 1.4 cubic feet.
Yeah, i will draw up some plots for the different configs before deciding.
anyone who can help me in this regard??
am using WinIsd.
Regarding getting crossovers designed, i think it would be better if i try to design it myself so i can gain some knowledge(even if it means making mistakes and more importantly learn from others)

Vivek, the towers are Wharfedale Diamond 8.4s.

Cheers,
Sachi

[Nappylady]

In that case, when you build your new cabinets, you should have a binding post and wires going straight to each speaker--that way, you can have your crossover outside the cabinet, and if you decide you want to try a different design, you can do so without having to invade the box.

This also gives you the option of going with an active crossover and bi- or tri-amping, which is very desirable.

[sachi]

okay, i have decided to build a new cabinet and go in for a passive crossover first.
as u rightly point out, i would like to keep the crossover outside and expweriment till i find the sound to my liking. but due to some reasons i will not be able to indulge in these apeakers for a long time as i will be leaving my hoemtown later this year.
hence, i think it would be better if i finish it once and for all with a passive crossover and get it over with. since this is going to be my first experience i donot want to over complicate things and leave things hanging. i want to be able to fire them up before i leave my hoimetown.


Btw, am having problems with partsexpress. it seems the Vifa midrange and the Daytons have been back ordered.only hope they make it in time so that they reach my friend before he leaves the US.
Can anyone with previous experience with parts express tell me if it is possible to change the shipping address and also does anyone know how long they take to get the drivers out on the road and give me a tracking code when they say a item is backordered.
i don't get it. they advertise that the product is in -stock. why is it back ordered?

Sachi

[Cal Weldon]

PE seems to wait until someone mentions it's out of stock to them for a day or so before they actually post that it is. Happened to me more than once.

As far as changing your address, try calling them direct **Call:*800-338-0531

Cal

[sachi]

Man, that's really frustrating.
had no such problems with speakercity from where i bought the tweeters.
i'll ask my friend to call them up and find out.
Thanks

[sachi]

Hello all,
I just got word that the drivers were delivered to my friend's place.
now that that is done. i am expecting the drivers to be here in India by the 1st week of June.
Now i have some basic design questions which i would like to get clarified.

I have been using the Winisd for designing a vented enclosure with the following specs.
the f3=27.15Hz
fb=27.45Hz and the Vb=2.7ft^3.
the group delay is abt 23.24ms (but the freq is off the f3 by 1 Hz,26.15Hz).
the vent dimensions are as follows.
dia=3inches
length=6.44inches
and vent mach=0.09

i have the following questions.
1> what is the relevance of group delay and the criteria for vented and closed.

2> i listten to all genres o music but i need my speakers to play Rock and metal well. so i guess the transients should be good. How do i obtain this.

3>Does a flat response mean a well designed speaker? what happens if there is a bump in the freq response and the response exceeds the reference level(0db) , call it a bump if u may.

4> considering the driver that i have bought and the kind of music i would listen to would a sealed enclosure or a vented enclosure be in order.


thanks for ur patience and looking forward to ur guidance.
Cheer,
Sachi

[sachi]

Are there no takers?

Is what i am doing right?