[ST7677]

Thanks LBM,
This was of great help...

Else I was unnecessarily getting biased towards Hertz Subs
Just calculated few of them
Hertz ES300 (site says 94db sensitivity) is actually only 88.4db!
Hertz ES300D (site says 97db sensitivity) is actually only 88.6db!
Hertz ES380 (site says 95db sensitivity) is actually only 88.2db!

Pretty comparable to all others

[ST7677]

But Hertz I can understand, as they are measuring in a different way...

What about ID? They measure at 1W/1m and still their numbers seem to be way off, how come...?

Image Dynamics ID12D2 v.3 - WebSite says 88.6, calculation shows 87.2db
Image Dynamics IDQ12D2 V.2 - WebSite says 90.2, calculation shows 87.4db
Image Dynamics IDQ15D2 V.2 - WebSite says 94.2, calculation shows 91.2db

Navin, some gyan from you will help here.... where are you?

[Rudra Sen]

My god!! I thought you've already decided on something what you like!!!

Take it from old man. More you delay, more you get confused. Atleast in this case...

[ST7677]

And the more you delay... the more you screw up your budget... lol

I completely agree with you Rudra. Actually, my BIL (brother in law) requested me to wait for my ICE install, he is planning to give me a visit soon...

So my ICE torture continues.... he he he

[rsjaurr]

My 10" infinty 1040 sub has sensitivity of 91dB rated at 2.83V @ 1M but acc. to formula it is only 85dB.
Now does that mean Harman Kardon is lying,i dont think so.
Sensitivity [and subsequently loudness]is very subjective thing and can vary depending on how its being calculated and ofcourse who has made/given that formula

[Bass&Trouble]

Originally Posted by ST7677

But Hertz I can understand, as they are measuring in a different way...

What about ID? They measure at 1W/1m and still their numbers seem to be way off, how come...?

Image Dynamics ID12D2 v.3 - WebSite says 88.6, calculation shows 87.2db
Image Dynamics IDQ12D2 V.2 - WebSite says 90.2, calculation shows 87.4db
Image Dynamics IDQ15D2 V.2 - WebSite says 94.2, calculation shows 91.2db

Navin, some gyan from you will help here.... where are you?

In what different way is Hertz measuring? Did you understand exactly how different? Let me try and explain.

Normal home audio standards has it to supply 2.83 volts to any driver/ system for sensitivity measurements. A lot of guys do exactly that for car drivers. Which is wrong. While home drivers/ systems 'usually' (not always) have a nominal impedance of 8 ohms, this means that 2.83V across it produces 1 watt of power. The same voltage applied to a 4 ohm speaker will produce 2 watts of power. There are some brands that will still refer to this as 1 watt of power as per standards (not in real terms), however absurd that may be.

In reality, this should mean that, if measured with 2.83V, a 4 ohm driver should show 3dB more than what the actual sensitivity is, on account of doubling the power. This seems the case with Image Dynamics (atleast 2 of the subs that you mention here)

My interpretation of the Hertz data is that, in the case of the SVC model (ES300/ 380) it's a 0.5m reading. Since distance is half of the legit 1m, there is a 6dB higher rating than what it should have been.

In the case of 300D, both voice coils have been fed one watt each, in addition to measuring at 0.5m. Hence 3 dB more on account of double power, and 6dB more for the halved distance. So the published spec is 9dB higher than actual.

Besides that, the sensitivity numbers have been rounded off to the nearest whole numbers.

Now you know what Dan was talking about.

[sk456]

I really dont seem to understand why everbody is so gung ho about numbers... the best test would be to actually hear the equipment..wudnt it??

WebSite says 88.6, calculation shows 87.2db

.. so whats teh big deal guys>>> can anyone seriously tell the diffrence ??... numbers logic jsut beats me.....

[ST7677]

Since it is not practical or feasible to listen to all of them, so
Reviews, Price and Specs would help me in shortlisting 3-4 subs which I can then hear and decide!

Anyway, don;t tell me that you didn;t look at the Power and sensitivity of the sub before buying it. I am just ensuring that the also mean the same thing

[low_bass_makker]

Originally Posted by ST7677

Since it is not practical or feasible to listen to all of them, so
Reviews, Price and Specs would help me in shortlisting 3-4 subs which I can then hear and decide!

which other models your are considering.......

[Autophile]

Every manufacturer has different ways of measuring the sensitivity of the driver same way as the amplifier manufacturer publish the power (1Khz, 20Hz-20Khz etc), distortion (1Khz, 20Hz-20Khz etc), damping factor (impedance and frequency)
etc.

If manufacturers are capable of measuring the thiele small parameters of any driver then I think measuring sensitivity is not a problem for them rather than relying on a formula.

There are lot of ways the sensitivity is specified as already mentioned 1Watt/m, 2.83V/m etc. It also depends how it is measured in free space, halfspace, anaechoic chamber etc.

Sensitivity does not decide the SQ of the driver. Any driver can sound better the one with lower sensitivity and on the other hand the one with higher sensitivity also. All dependent on design and materials.

Like SK said trust your ears rather than numbers.

[ST7677]

Is there anywhere I can experience these drivers in Bangalore?

I am looking for a decent 600W RMS capable driver at 2 ohm to extract all from Pioneer D510.
Would prefer a single sub rather than 2 of them.

What are my options? (Please suggest along with prices.)

[sk456]

Originally Posted by ST7677

Anyway, don;t tell me that you didn;t look at the Power and sensitivity of the sub before buying it. I am just ensuring that the also mean the same thing

Frankly I didnt look at any numbers what so ever.... just heard a couple... read a few reviews on team-bhp... knew what kind of sound i wanted and went for it....

[low_bass_makker]

Originally Posted by Autophile

If manufacturers are capable of measuring the thiele small parameters of any driver then I think measuring sensitivity is not a problem for them rather than relying on a formula.

There are lot of ways the sensitivity is specified as already mentioned 1Watt/m, 2.83V/m etc. It also depends how it is measured in free space, halfspace, anaechoic chamber etc.

Sensitivity does not decide the SQ of the driver. Any driver can sound better the one with lower sensitivity and on the other hand the one with higher sensitivity also. All dependent on design and materials.

ya it is true every manufacturer can promote its product by messing the numbers or try to fool the user...

If one has to compare two products how one will do ......is there any method to do so.....

also the formula given above is absolutely correct there is no doubt on that as it will good comparision about to drivers what say navin ji, sam bhai, Partner B&T ..........would you people shed some light on this.....

also nowdays standards are made so that the consumer get the right product like the cea standard for the rightfull comparison of the amp specs in which real picture is revelled to the user......other wise the day will be not far when a 112db senstivite speaker will be avalable in the market......lol

and measuring the theile parameter measuring is not a big thing if one has the follwoing stuff which are not very expensive for any speaker manufactuer to get ...

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

and quote the correct values....

[low_bass_makker]

Originally Posted by sk456

Frankly I didnt look at any numbers what so ever.... just heard a couple... read a few reviews on team-bhp... knew what kind of sound i wanted and went for it....

99% of the people does not know what the specs really are and they listen and decide but if one has a interest in knowing some thing one should know about if fully......

[speedzak]

ST, you're simply running on wet ground when you can easily take the road.
The sensitivity good or bad, I found the Hertz Subs better sounding than the Pioneer, Sony, Kenwood, Blau, Audiobahn and JBL subs of same category. And this is after hearing these in similar setups and is purely my personal take.
Man! If you make some effort, you'd be able to get the shopkeeper demo you things. Try it!