t/s specs for indian drivers

Status
Not open for further replies.
Jump to Latest
#601
Hi Suranjan,
Thats gr8 insight u have given me. As u said may be I take up the cabinet building project back in India when I have professional help of Carpentars. 😀
I am seriously looking at the knowdown kits available in US with in my price range. as I plan to take these project speakers and electronic gear back to India. Will dump Wharfdale and B&Ws here.

To start with I have done some home work on the available kits in US. I will post those links once my study is complete (give me this sunday for this activity, or my wife will kill me if I surf NET on sunday morning here.)

Mean while if you can send me the kit details at my khanmadari@yahoo.com ID it would be great. BTW I am regular subscriber of Sound and Vision Mag here. If you can suggest few DIY Mag also, it will be help to me.

thanks in advance.
 
#603
Hi Suranjan,
Yes, i did break in the day I got it...you must be right, it gets better with time. Dont have the spider size- its already screwed & sealed in cabinet w/synthetic glue.
Tried the Linkwitz transform - (although cabinet is vented). It just boosts freq upto 70Hz. It doesnt seems to extend the Lower freq. Doubt the driver is capable of going below 35Hz. Tone signal doesn't sound clean below this.
 
#604
hi roshan

too bad about the woofer from mp. seems some thing is wrong .... tell me some thing will the intenal volume being redued by jus this much effect the over all out put .... i'm not sure .... or may be the woofer it self is not able to take it ..... i'm not sure here again as mp woofers are known to be good .... why don't u try a enclosed set up as navin had mentioned earlier may help .... u never know.:devilr:
 
#605
i was missing in action as my laptop died. took me some time to buy a new one (DELL) and send the old one (SONY) to be revived. so u will se more the the usual typos now. the keyboads are not the same!

like i have said before mp's woofers seem to be designed for a small sealed box. at the av max expo they boomed a lot. part of that was poor room and installation (corners).

if you are expereincing the same phenomenon, i would suggest that if you have a bass relfex box try plugging the port. if you have a sealed box try making the box aperiodic.

The idea is to control box losses and damp the boom. let me know how you fare.

BTW also email MP. he is very helpful.
 
#606
hi

navin - all i can say (ref above woofer) is that have you gone thru the personal mail i sent you - (regarding china)

by the way when will you be sending me the frame size - i will be samling you the woofers (please dont ask me why - but thats the way i like it to be)

roshan

if you can manage a high current amplifier - one with a real heavy power supply - you will find the sound improving

and if you can put in active bass correction filter - came out in elektor if you want the issue dates ets ill send it across (it linearises - the pre amp stages frequency to 25 hz or so )

- suranjan
 
#607
First of all, i wouldn't pass this off as a bad woofer - at least not yet. Had a function at home yesterday - one of the guest was an audio expert. Instantly he was able to recognise an echo (had shifted my house recently) - albeit there's furniture - said the room accoustics was terrible - need more drapes.
Now, hanging extra drapes around is going to look stupid & moreover expensive. My windows already have curtains. Is there some cheaper yet efficient alternative?

Suranjan - I would really appreciate if you could let me know the issue date of the filter published in elektor. As a matter of fact i recall Elektor publishing a popular schematic on surround sound processor w/delay, sub filter & sub amp. Not sure if this is what you're referring to.

navin said:
like i have said before mp's woofers seem to be designed for a small sealed box.
Click to expand...
This is contradictory to taruns statement that MP's subs are suitable for vented.
Plugging the port w/felt was a good idea but in my case didnt help. Theres reduction in SPL and it killed the low frequencies.
 
#608
Get the TS parameters first.

Since there are so many ways to get the TS parameters, you should measure them. That way you have an idea of what is happening. Without all that you are groping in the dark.

If you can't do it, get help - lots of DIY guys in Bangalore.
Cheers.
 
#609
#610
The speakercity kit.

The Speaker City kit looks very nice.
I would pick that as the bass end can be tailored to your needs.

The North Creek unit I would pass . The Adire would also be OK but may not be as good as the two piece unit from speaker City.
Cheers.
 
#611
roshan101 said:
said the room accoustics was terrible - need more drapes.
Now, hanging extra drapes around is going to look stupid & moreover expensive. My windows already have curtains. Is there some cheaper yet efficient alternative?

.
Click to expand...

hi roshan , room acoustics is a great thing it can even make a bad system sound good if placed well ..... usually jus drapping the room won't help infact woofers need a bit of reflection too. so jus draping of one or two walls would do the trick. one more way is to move around the room with the woofer ..... but you need to sit in the sweet spot ..... while it is being moved and you can pin point the best position.

as of now any improve ments .... challlo see yah
Binil
 
#612
thanks suranjan for the vote of confidence. i will get the frame size to you asap. once you are done let me know i will try and ask a friend in cal to ship them out to me. also you can email in private the cost of the these drivers. the box i have made is about 1.2 cu. ft (30-35 liters).

since the box has curved sides it is diffcult to gauge the exact box volume but i figured since thebox is sealed and we are looking at sealed boxes a 5% error in box size is not going to matter that much.

BTW my sony is up. the date i seem to have lost (due to corrupted CDs) some photos (jan-today) of my son.
 
#614
roshan101 said:
This is contradictory to taruns statement that MP's subs are suitable for vented.
Click to expand...
MP had sent me some T/S parameters, and the Qts was 0.39, IIRC. I thought that sort of Qts may work better for vented than for sealed, but there's no reason to not try sealed. And when you do try sealed, it's expected that the SPL at low freqs will drop, and if the woofer is mechanically strong enough, some Linkwitz Transform may help things. You need very good excursion, though. It's possible that MP's drivers have good Xmax.

I didn't give the T/S parameters much thought at that time because I was more interested in a high-Qts driver for open baffle, and MP too said that his drivers may not be very suitable for such speakers.

All this is textbook theory, BTW... I haven't really built anything with his drivers.
 
#616
Check the EBP.

The EBP ( Efficiency Bandwidth product) = Fs/Qes.
If you don't have Qes , Qts may be reasonably close .
For sealed box use EBP is generally less than 50. For Vented box use EBP is more than 100. In between is a grey area and you can use either enclosure. This is only a guide and NOT a hard and fast rule.
Closed boxes need drivers with Qts on the higher side ( >0.35) otherwise you might loose some LF extension.
Better to simulate it with some software . For free software go to the FRD web page. I don't have the URL right now.
But there are so many others mentioned somewhere in this forum.

It is very hard to absorb LF signals and certainly not possible with curtains and absorbent panels we generally use for midrange. Only resonant systems can do that easily.
The woofer position will excite room resonances and that is where the problem is.
One 'crazy' method was to place the woofer in the listening position ( on the sofa ?) and then crawl around the room ( funny eh !) in the area you want to keep the sub and see if it sounds OK there . Any boom means you have to move on ! When you find a location that sounds OK , you can place the sub over there.
Cheers.
 
#618
Qes : 0.40, Qts : 0.38, EBP=80. So, its a grey area - preferred to go with vented. Have already posted this earlier in this thread.
Never knew LF signals are hard to absorb. Ashok, thanks for enlightening. Will try your crazy method of crawling around.

Binil, Thanks for those links. There's a wealth of information in there.
 
Status
Not open for further replies.
Top Bottom