[s0uljah]

st7677, I had a similar thread runnign sometime ago...

Why dont you consider the option of 2 * JBL GT4 - 12" SVC in a calculated sealed enclosure ?
Similar to what amit_sound has in his accent... though he has been adventurous and used to 15"ers !!

If your going with JBL and budget permits it, go for one of their monoblocks, that was my dream,
but righ tnow im going to have to make do with the amp I have. Otherwise there's a few amps
mentioned in th elink I provided above

[ST7677]

Thanks S0uljah,
But I am on a tight budget and from various thread I figured out that Pioneer D510 is more value for Money than JBL 300.1CS.

Initially due to space constraint I was only thinking of 1 driver, but as this amp can drive 2 subs, I am thinking of may be 2 pio 12" subs or a single JBL 15".
I do not think Pio has a 15" sub and JBL does not have DVCs in this range?

I need sub amp & subs within 15-20k.

[speedzak]

If you're really interested in making your subs musical and not just thump, then try Hertz E 300 (SVC) or 300D (DVC) Subwoofers. They sounded far better than Pio to me. I'd recommend you give it a look before you finalise. Even E380D (15 incher) is a marvellous and very Musical Sub. And it doesn't cost gold.

[ST7677]

Hertz E 300 (SVC) or 300D (DVC) Subwoofers

How much do these cost?

[s0uljah]

Unsure regarding price.

Since your budgeting and opting out of JBL for this reason and going with pioneer, I think the Hertz might stretch your budget as it costs a little more than JBL.

Alternatively, invest in a good amp which can support 2 subs and start with one subbie for now. and add the second one when the time is right.

I had the 306svc in our lancer, it isnt that great.. but definately bang for buck!

[speedzak]

Originally Posted by ST7677

How much do these cost?

I think it's somewhere around 7-8k. (yes, I'm thinking).
You can contact your dealer for the exact prices or PM Gunbir.

But as Souljah said, dont go for a lower brand due to budget. Get the best you can afford right now. Go with a one Sub setup for now. Or leave the Sub totally and get a great amp, components and Cables for now. Gather some more moolah and upgrade gradually. You'll be more happy with quality stuff in your car rather than quantity.

[ST7677]

Ok thanks to you guyz, I have once again started thinking of increasing my ICE outley...
At least now I am thinking of going for Hertz Sub
And may be Audison / Alpine amp for compos...


But still lots of questions in my mind...

Our dear old man (Navin), kept saying that it's the speaker sensitivity which matters and I could not interpret it till today when I realized that...

A speaker with a sensitivity rating that's 3 dB higher than another speaker's only needs half as much power to deliver the same amount of sound!
i.e. output of following 3 speaker will be same!!!
85DB speaker @ 100W
88DB speaker @ 50W and
91DB speaker @25W

Q1. Is it just a theoretical equation or does it really holds good (does it really mean that 1 88DB speaker at 50 W = 2 85DB speakers at 50W or = 1 85 db speaker at 100W in reality?

Q2. Does sensitivity hold good only at low wattages or is it good enough for entire wattage range of the speaker (I mean if sensitivity is measured at 1 W then speakers may be tuned to be more sensitive in that region)

Q3. Besides Sensitivity and RMS, what are other important things to SEE in the speaker specs...


Of course the other thing our old man say is listen with your ears and then decide, so would I...

[low_bass_makker]

Originally Posted by ST7677

85DB speaker @ 100W
88DB speaker @ 50W and
91DB speaker @25W

ya this is true till the stuff compared is rated at the same rating.....

like some rate it at 1 watt / 1 meter
some at 1 watt / .5 meter
some at 2.83 volt / 1meter

this can only be true if one compare the spec with the volt/meter same....

there can be speaker louder with 88 db sentivity written in the specs if compared to a 91 db speaker......

So from my side leave senstivity to a side while deciding a speaker....but make sure that all the speaker should be of same make so that u can easily compare the specs....

all the other specs will confuse a lay man ..... dont go comparing them do what navin ji has said "listen to the speaker then decide" ........this is bottom line while deciding for a speakers for ur car.....and the budet......

[speedzak]

Your choices seems to be improving day by day!

You have almost got a qualty setup coming your way! So, do the install soon and get it rolling.

[Bass&Trouble]

Originally Posted by ST7677

A speaker with a sensitivity rating that's 3 dB higher than another speaker's only needs half as much power to deliver the same amount of sound!
i.e. output of following 3 speaker will be same!!!
85DB speaker @ 100W
88DB speaker @ 50W and
91DB speaker @25W

Q1. Is it just a theoretical equation or does it really holds good (does it really mean that 1 88DB speaker at 50 W = 2 85DB speakers at 50W or = 1 85 db speaker at 100W in reality?

Above statement is entirely true.

LBM very precisely pointed out that the standard for the sensitivity measurement should be the same before we get down to comparing them.

Originally Posted by ST7677

Q2. Does sensitivity hold good only at low wattages or is it good enough for entire wattage range of the speaker (I mean if sensitivity is measured at 1 W then speakers may be tuned to be more sensitive in that region)

It hold good for any amount of watts (power input), but I suppose you mean 'low frequency or entire frequency range'. The measured sensitivity is usually in the operating band of the speaker to be measured. If not, the sensitivity is not a true picture. For example a tweeter's sensitivity measured across 20-20000 Hz would be unfair and yield a very low averaged value. This is of no use to a system designer. I refer to the frequency response graph when i have to very precisely study the sensitivity and response charachteristics. That is the best way.

Originally Posted by ST7677

Q3. Besides Sensitivity and RMS, what are other important things to SEE in the speaker specs...

Very briefly, this depends on the drive unit. For a sub, the T-S parameters like Fs, Vas, Qts etc are very important for enclosure considerations. For a tweeter, you'd like to have the frequency response curve, sensitivity etc. So varies based on the need. Wattage is important for everything so that you can accordingly select a suting amp.

Edit: I'm trying to remove the bold parts of my text but it shows up as normal text in the editor and bold in the thread. ???

[navin]

B&T shame on you. even a PC-Newbie like me managed. :-)

[ST7677]

ya this is true till the stuff compared is rated at the same rating.....

like some rate it at 1 watt / 1 meter
some at 1 watt / .5 meter
some at 2.83 volt / 1meter

So how do we compare sensitivity in 1st & 3rd scenario i.e. (W/m vs V/m)

I know Hertz measures in V/m and probably due to this their sensitivity seems to be higher than others...

[low_bass_makker]

SPL is one of the most misused and maligned driver parameters out there today. Because most know that SPL has something to do with the loudness of a driver, they think bigger is better. And in general, it is... But recently, some manufacturers have taken to using unusual steps to "rate" the SPL of a driver. These can range from using non-standard drive levels, to measuring at 0.5 meters, to using in-room calculations. And unless they tell you what they used, you're out of luck! Or are you... Actually, no! There is a way to actually CALCULATE the efficiency of a driver. That is, you can run some simple equations, and come up with measure of just how efficient a driver is at converting electrical power to acoustic power. And from that, you can easily get to SPL. So now, you can actually "level the playing field" by removing any bias from the manufacturer's numbers...To start with, we'll need some of the basic Thiele-Small (T/S) parameters. I assume you can at least get these. If not, then take EVERYTHING that manufacturer says with a HUGE block of salt! If they aren't going to give you the absolute basic parameters about your driver, well...
Anyway, what you'll need is: Qes, Vas, and Fs. Yes, with these three little parameters, you can calculate the effective efficiency, and subsequently the SPL, of a driver. Here's how you do it:

Efficiency = 9.64 * 10^(-10) * Fs^3 * Vas / Qes

where
10^(-10) is ten to the minus ten power (0.0000000001)
Fs is the resonant frequency of the driver, in Hz
Vas is the equivalent compliance of the driver, in liters
Qes is the Q of the electrical system of the driver

This will give you a number, usually called n0, or eta naught. And, it's usually expressed as a percent, so multiply by 100.
Now, n0 is a measure of the efficiency of power conversion of the driver. That is, it tells you what percent of input electrical power is converted to acoustic power. Thus, you can calculate the output acoustic power by multiplying the input power by n0.

Now, don't be scared of a number down below 1% (0.01)! Rather, this is VERY typical of most subwoofers. Yes, drivers are inefficient, but that's what we've got to work with... So, how do we calculate the SPL of a driver from n0? Use the following equation:

SPL = 112 + 10 * log(n0 )

Where
n0 is the efficiency calculated above
log is the base-10 logarithm
SPL Calculations 2

So, let's run an example. Say, our Shiva subwoofer driver. For starters, we have: Fs=21.6 Hz, Vas=136.6
liters, Qes=0.3996. So, the n0 would be:
n0 = 9.64*10^(-10) * Fs^3 * Vas / Qes
n0 = 9.64*10^(-10) * 21.6^3 * 136.6 / 0.3996
n0 = 0.0033 or 0.33%

Now, let's put that into SPL:
SPL = 112 + 10 * log(n00 )
SPL = 112 + 10 * log( 0.0033 )
SPL = 87.21 dB SPL @ 1W, 1m

That's the 1 Watt, 1 meter sensitivity of Shiva. Go ahead and run your own favorite driver, and see if the manufacturer's being straight-up with you!

the above is taken from adire audio web site.....this formula will help one to atlest compare the driver with there actual senstivity......

[Bass&Trouble]

Originally Posted by low_bass_makker

the above is taken from adire audio web site.....this formula will help one to atlest compare the driver with there actual senstivity......

Dan Wiggins is one superstar!

[low_bass_makker]

some thing more on the driver senstivity part let us shed some more light on this....

http://www.the12volt.com/installbay/...TID=73962&PN=1

some good detail on the senstivity calculation

http://www.mhsoft.nl/Reference.asp

here is a calculater to find the senstivity of the driver....

like take example of adireaudio bramha
fs-29
vas-22.7
qes -0.4
results comes out to 83.2 accurate as suggested by the manufacturer....

the famous xxx sub....

fs-27
vas-56.5
qes-0.44
results comes out to 85.8 as suggested by the manufacturer 85.9 hardly any differnce...



lets us take a popular pioneer 306c..
fs-32.9
vas-51.76
qes-.5
result comes to 88.2 as compared to manufacter 89 state still close...

one can do it to the woofer one person is going to buy...how much the manufacturer is cheating on him......


people please do it for ur speakers and do post the results.....