2 ported or 4 sealed? in a car

[BP1Fanatic]

Originally Posted by scampo77

thanks BP1 for all this info but they both seem like sales pitches for these speakers. from what info i have gathered it seems that these wont work well in a sealed box and i think i should stick to a ported box.

the spec that makes the most amount of sense is....
6.0 ft3 (170L) + port displacement
3.5 x 16.25” (8.9x41cm) port, 13.75” (35cm) long
Power Handling = 750W RMS
box size determines max power i can use? is that right? the reason i ask is because i bought these speakers blown up and i have put new coils in them. when i reassembled the speaker i just machined pieces of steel that hold the surround and the spider in place. so if i blow the coils again i can easily pop new ones in. so want to drive these speakers as hard as i can because i really dont have much to lose. i have 1200 watt for each speaker and i have 4 of these amps. so why not drive them with as much power as possible? (this is a serious question)

my question is, if my options are between

3.25 ft3 (92L) + port displacement
3 x 13.25” (7.6x34cm) port, 14.5” (37cm) long
Power Handling = 600W RMS

OR ...

6.0 ft3 (170L) + port displacement
3.5 x 16.25” (8.9x41cm) port, 13.75” (35cm) long
Power Handling = 750W RMS

then what will be my trade off? because this is my exact question which i started with. because i have space and power to drive 4 of the first box or 2 of the second box.

i gotta say, glowbug you have really raised one of my eyebrows at that link you sent of those 4 speakers. i will definatly be considering them for the next upgrade. for now however i need to stick with the equipment that i have on hand and try to make something work.

No problem! The "6.0 ft3 (170L) + port displacement 3.5 x 16.25” (8.9x41cm) port, 13.75” (35cm) long Power Handling = 750W RMS" is for the 15! That's why I put the 12" specs in bold and underlined them.

[event horizon]

Originally Posted by BP1Fanatic

That's why I put the 12" specs in bold and underlined them.

I'm sorry but having seen this i really must ask

What are the driver specifications?

For a good while i have been looking about at lots of car subwoofers simply because the boys want high SPL. Most manufacturers don't list such things as QTS,QMS,QES etc etc but they might state some ridiculous Xmax.

Having purchased an un-named driver & received a nice spec sheet with the thing i doubt it'll come as much of a surprise that the measured QTS of the driver (admittedly not broken in) was 0.89 when the quoted QTS was under 0.39.

Yes it may well alter given a week of a decent amount of power as FS with adjustments as the resonance drops, but what i'm getting at is where are the "REAL" driver specifications other than someone saying "it'll work well in box size X"?

Work well for who? For you?

If i'm designing for a flat response & high excursion in a "hifi" system i need more than "it'll work ok in this box be it sealed or ported"....

Specs please

E2A:- Someone mentioned RE Audio drivers, if there specifications are accurate then even the cheap RE 8/10/12 D4 speakers are seriously good value for money Why can't other car sub manufacturers quote specs?

[scampo77]

that seems very valid considering that i have changed the coils in these speakers. can anyone link me to a webpage instructing me how to measure these things? if i learn how to do it on one speaker is it the same for all speakers (even midrange)?

[event horizon]

Originally Posted by scampo77

that seems very valid considering that i have changed the coils in these speakers. can anyone link me to a webpage instructing me how to measure these things? if i learn how to do it on one speaker is it the same for all speakers (even midrange)?

I'm asuming you mean how to measure driver specs?

If you weren't addressing me i apologise

Look for a book by radio shack, can't remember the name but it is to do with designing & building loudspeakers. Red cover from what i can remember with a kind of cartoon pic of a speaker assembly on the front

It'll instruct you on how to measure just about every driver parameter you need to know, frequency doesn't really matter - same theory & practise applies to midrange drivers & tweeters.

All you'll need is a function generator, a precision resistor & a voltmeter. With those you can measure damn near every driver parameter. If i can find this book (which is in bits i might add) i'll let you know the proper title

[tsmith1315]

Originally Posted by event horizon

Look for a book by radio shack, can't remember the name but it is to do with designing & building loudspeakers. Red cover from what i can remember with a kind of cartoon pic of a speaker assembly on the front

Or The Loudspeaker Design Cookbook by Vance Dickason, or for the quick route buy the woofer tester ($99?) from partsexpress.com

[BP1Fanatic]

Originally Posted by event horizon

I'm sorry but having seen this i really must ask

What are the driver specifications?

For a good while i have been looking about at lots of car subwoofers simply because the boys want high SPL. Most manufacturers don't list such things as QTS,QMS,QES etc etc but they might state some ridiculous Xmax.

Having purchased an un-named driver & received a nice spec sheet with the thing i doubt it'll come as much of a surprise that the measured QTS of the driver (admittedly not broken in) was 0.89 when the quoted QTS was under 0.39.

Yes it may well alter given a week of a decent amount of power as FS with adjustments as the resonance drops, but what i'm getting at is where are the "REAL" driver specifications other than someone saying "it'll work well in box size X"?

Work well for who? For you?

If i'm designing for a flat response & high excursion in a "hifi" system i need more than "it'll work ok in this box be it sealed or ported"....

Specs please

E2A:- Someone mentioned RE Audio drivers, if there specifications are accurate then even the cheap RE 8/10/12 D4 speakers are seriously good value for money Why can't other car sub manufacturers quote specs?

http://kicker.com/sites/default/files/L7_0.pdf

Model: 08S12L72 Averaged 08S12L74 Averaged
Norm Imp 4.00 8.00
SPL 87.27 87.47
Lem 3.825 5.420
Reve 3.86 6.77
Sd 0.0645 0.0645
BL 20.06 25.44
Vas 45.55 45.46
Mms 264.98 247.53
Fs 34.93 31.55
Qms 6.258 5.744
Qes 0.504 0.586
Qts 0.511 0.532

Model: 08S15L72 Averaged 08S15L74 Averaged
Norm Imp 4.00 8.00
SPL 89.28 89.43
Lem 4.085 6.284
Reve 3.69 7.10
Sd 0.1056 0.1056
BL 21.10 27.90
Vas 156.56 165.66
Mms 374.43 351.15
Fs 26.2 26.28
Qms 7.489 6.579
Qes 0.511 0.529
Qts 0.478 0.490

Model: 06S15L72 06S12L72 06S10L72 06S8L72
Nominal Impedance(Ohms): D2 D2 D2 D2
SPL dB 1W/1M: 89 88.6 86.1 83.4
Displacement, cc: 4530 2475 1830 980
Displacement, cu.in.: 276.5 151 111.8 59.8
Hole cutout, in dia: 14 1/16 11 3/16 9 1/2 7 5/8
Mounting Depth, in: 8 1/2 6 11/16 6 3/16 4 11/16
Revc: 3.56 3.73 3.645 3.305
VC Inductance, mH: 3.98 3.81 3.089 2.77
Sd, m3: 0.1056 0.0645 0.0439 0.0273
BL: 21.395 17.93 17.16 14.29
Vas, Liters: 179.3 65.55 34.3 10.075
Vas, CuFt: 6.33 2.31 1.21 0.36
Moving Mass , oz.: 12.73 6.97 6.13 4.83
Fs: 24.2 33.1 33.1 44.1
Qms: 6.8965 6.191 6.239 7.064
Qes: 0.4515 0.503 0.4745 0.614
Qts: 0.424 0.465 0.441 0.5645
Peak Power Handling, watts: 2000 1500 1200 900
EXmax, mm: 16.1 14.1 13.9 12.2

[Glowbug]

Why can't other car sub manufacturers quote specs?

The good ones do

[Brian Steele]

Originally Posted by Glowbug

The good ones do

Quoting specs is one thing.

Quoting accurate specs is another.

Time for sub manufacturers to supply "birth specs" with their subs... :-)

[BP1Fanatic]

Originally Posted by Brian Steele

Quoting specs is one thing.

Quoting accurate specs is another.

Time for sub manufacturers to supply "birth specs" with their subs... :-)

I agree

[event horizon]

Originally Posted by tsmith1315

Or The Loudspeaker Design Cookbook by Vance Dickason

That's the one It looks in vastly better condition than my copy!

Originally Posted by BP1Fanatic

http://kicker.com/sites/default/files/L7_0.pdf

A lot of the time i can't find any, in fact that may well be the first time i have seen specs for Kicker drivers

Originally Posted by Glowbug

The good ones do

Yes, i tend to agree - they also tend to be pretty accurate or at least in the ball park.

Originally Posted by Brian Steele

Quoting specs is one thing.

Quoting accurate specs is another.

Time for sub manufacturers to supply "birth specs" with their subs... :-)

& there i rest my case!

Ok, it doesn't matter too much in my case as i'll be using these drivers i have in a sealed enclosure. The resulting peak can be taken care of with some simple electronics like a Linkwitz-Riley network.

If i'd have wanted them to work in a reflex going on the so called manufacturers specs it'd be a nightmare