Sound quality vs SPL parameters

[MyNameIsNoob]

Ok ive been reading all i can on T/S parameters looking for and comparing the favorability of subs for different uses...

Jus looking for a common denominator or an axiom to help me understand how they (theoretically) will affect each other.

Ive already read the definitions more than once, but its the way they affect the sound that interests me... ONLY BY READING THE SPECS (havent heard any of em), Id guess the massive audio to be the loudest and the FI to have the best SQ. I know, like anything, this is rarely the case bc of variables like under/over rating and the rest of the parameters i havent listed... but thats why im tryna get a better understanding of the fundamentals, so i can make better sense of the numbers... And im an info sponge, so "each sub is different, gta listen to em" wont help me any lol, but thx in advance!

Brand / Model........................Size...........RMS.......... SPL........ Xmax........ FS........ QTS.......... Magnet

Massive Audio Hippo152....... 15"........... 2000......... 98............ 15mm...... 34.2..... .374.......... 320 oz

Sundown ZV.4REV.2..............15"............1750......... 86.5........ 35 mm................... .45.....................

Soundqubed HDC3.115 ........15"............1500......... 91.5........ 36 mm...... 38......... .419......... 340 oz

American Bass HD15D2 ........15"............1500.......... 91.5....... 30 mm...... 31.7...... .382.........300 oz

FI BL15.................................. 15"...........1500......... 91.8.........18mm....... 33.8..... .27............ 261 oz

RE SXXV215D2..................... 15"........... 1200......... 90.6......... 24mm.................... .38......................

NVX VCW152.........................15"........... 1000......... 87............ 20mm...... 24......... .36............195 oz

(added a 12 bc im curious how or if the 46mm excursion makes up the difference in the volume of air moved compared to any of the above... Can i multiply the SD by the excursion to figure this out?)

B2 HN12V2............................ 12"........... 1500.........89.2.......... 46mm...... 32.5...... .38.......... 300 oz

*Didnt list all the parameters for obvious reasons, but of course im interested in understanding those too... and always wna hear your thoughts and opinions on other brands i havent listed...

[ShadeTreeMechanic]

I'm sure someone can shed light on this. I have heard that T/S parameters are just theory and can change once a driver is broken in. They don't take into account the coil being powered either. This is why a driver might look like the specs are crazy and it ends up being perfect for what you are doing. I would recommend figuring out the boxes and tuning for each one to get a feel for what the different parameters do. The old way of pencil and paper is best to help see. Calculator if you must. My 2 cents.

[Triticum Agricolam]

The specs you have listed aren't going to really tell you which sub sounds better or which one will get louder, they can give you an idea what box specs each particular sub will probably work well in though.

The SPL number listed for subs isn't very useful, there isn't a standardized way to calculate it so comparing it across manufacturers is meaningless.

One spec that is a little bit of an indicator of sound quality is inductance divided by DC resistance (Le/Re). The smaller number the better. Its just an indicator though and by no means will it difinitively tell you what sub will sound better. A lot manufacturers don't publish the Le spec on their subs either.

Multiplying the excursion by the cone area can give you the swept area of a subwoofer, which is related to how loud it can play and certain frequencies. So it does kind of make up for the difference in cone area between a 15" sub and a 12" sub. While both subs make have similar swept area and thus similar max output, the 15" sub will use less power to produce the same output as the 12" (generally speaking and dependant on what frequency is being produced).

[ShadeTreeMechanic]

One thing I find interesting is the ratio of cone area to voice coil diameter. Multiple small drivers will have a tighter and quicker response than fewer large drivers. Even though they can play the same frequency it will still sound different. Mass of the cone and coil along with the motor BL play into this as well. I like the sound of 4 10 inch woofers along with 2 15 inch subwoofers. The 10s give plenty of kick and the 15s can dig down low. Either playing the same on the same amp or separate amps crossed over around 50hz. Tens 50hz up to about 150hz and 15s play 50hz and down. (separate amps and playing different frequencies might negate the need for any time delay) This can give the best of both worlds.

[Triticum Agricolam]

One thing I find interesting is the ratio of cone area to voice coil diameter. Multiple small drivers will have a tighter and quicker response than fewer large drivers. Even though they can play the same frequency it will still sound different. Mass of the cone and coil along with the motor BL play into this as well. I like the sound of 4 10 inch woofers along with 2 15 inch subwoofers. The 10s give plenty of kick and the 15s can dig down low. Either playing the same on the same amp or separate amps crossed over around 50hz. Tens 50hz up to about 150hz and 15s play 50hz and down. (separate amps and playing different frequencies might negate the need for any time delay) This can give the best of both worlds.

I know your experience is that 10"s give good kick and 15"s play low, but those really are generalizations and are only half the story. There are plenty of 15"s that have good kick (like what are in most PA systems) and you can make 10"s play as low as you want to go, you just have to have the right 10"s in the right box.

[yurvalentine]

For real. My 10" Mayhems peaked at 38hz, and could play down to around 25 pretty god damn well.

[ShadeTreeMechanic]

Sure 10s can be tuned low and 15s tuned high. I guess my point was to divide the spectrum amongst more drivers. Like for front speakers you could have a 4 inch mid with a whizzer cone. Will it play a wide range? Sure, but we do one better by having a separate tweeter targeted at the high end. Then we can have 3 way separates. Next would be some mid bass speakers (which is really just a big midrange). Then there is what I was trying to explain about bass and sub bass. Just something to think about.

[MyNameIsNoob]

Im always afraid of inefficient speakers or subs lol so i tend to shy away from anything below 90, unless its an 8 or a 10, but i havent had anything smaller than a 12 since my 3 JL10w6's n that was goin wayy back lol... buut anymore i been leaning toward a better sound, even if its at the expense of volume so ive been considering 2 8's firing down from under my dash for jus daily use when i dont wna beat the block up. Been looking at using an 8" Image Dynamics for this bc i always liked their sound, but i been out of the loop awhile so idk ab all the new stuff, but the specs seem like theyd be a good fit...

Ive read a few articles saying that a good indicator of a sub that has good SQ is what you said Le/Re, a high sensitivity, low QTS, light moving mass and a strong motor to control the direction of the cone quickly... If you were reading a review on a particular sub you havent heard, what are the specs that do matter?

[ShadeTreeMechanic]

Eight inch woofers up front would be great if you could fit the box. I have seen 8s in doors along with the separates but if it was an 8 inch sub then it might make the midrange flap around too much.

[Massivespl]

Seems tricky to mount 2 8" woofers under the dash properly... Just properly deaden your doors and get some nice speakers in there of even a AB 6.5" or sundown 6.5"