JLW7 vs DD 3500d

[dvrmstrng 5,000+ posts]

and i wanna come hear it when you get it since were both in NJ and im gonna kill you with SQ and SPL

 

[Towncar 10+ year member]

and i wanna come hear it when you get it since were both in NJ and im gonna kill you with SQ and SPL

hmm

 

[Country 10+ year member]

what brand is dd

 

[Towncar 10+ year member]

what brand is dd

DD is DD

Digital designs

 

[Immacomputer 10+ year member]

what brand is dd

Somebody didn't search google with his dumb ass..

http://www.google.com/search?source=ig&hl=en&q=dd+car+audio&btnG=Google+Search

 

[audioholic 5,000+ posts]

Back to the two speaker scenario, two speakers with 2" p2p linear travel, one gets there with 100watts and one gets there with 1000watts, do they both have the same level of sound? Is the efficiency we are talking about reaching linear travel, or producing sound?

The efficiency is in cone excursion (what you are calling linear travel).

The physics (very very basic). A speaker creates sound by moving back and forth to create sound waves in the air. All other things being equal, the more the cone moves, the more air it displaces, the louder it is. That statement is based on same sub, same box, same install. That statement is NOT saying the sub whose cone moves more is always louder. If you compare different installs, other factors come into play...

As already stated in this thread, subs in ported boxes tend to have less cone motion than their sealed counterparts, yet get louder. Futher more, just looking at the ported box, you may note that as the frequency of the signal gets lower and lower, closer and closer to the enclosure's tuning point, cone motion goes lower and lower, yet output goes up. Defies logic and seemingly physics, right? The difference is in the enclosure, it also has an efficiency, which is based around its tuning frequency. A ported box is most efficient at or near its tuning freq, the further you deviate from it the less efficient the box this. What this means is, as that signal freq dips lower and cone motion decreases, direct output from the sub is decreasin but enclosure efficiency is going up even faster.... net result... less cone motion but still more over all ouput.

Now that that's settled, lets go back to subwoofer efficiency. Two different subs playing in sealed boxes with the same alignment (for simplicity). Each sub's cone is moving 20mm for example. Sub A moves this 20mm with 1,000 watts input power, while sub B does it with 100 watts input power... which is louder? They will be the same. Remember, the basic physics behind the loudness of the sound is by how much air each sub is displacing. If they are the same sized subs, and they both have the same cone excursion, they (in theory here) are moving the same amount of air, and thus will have the same output volume. So, squeak's point is if you can get the same cone motion from a more efficient sub with less power, why would you chose the less efficient route?

Less efficient means more electrical drain on the charging system, which means more voltage problems, which means less performance. At the very least you will be spending more money to stiffen your charging system to adequately power the less efficient driver, while not gaining any performance over the more efficient setup.

In SPL it becomes more about how much power the sub can absorb in short burps. Those SPL rigs are playing very near enclosure tuning, cone motion is at its least (the enclsoure is choking down on the down, dampening its cone motion greatly), xmax is less important than the simple ability to absorb lots and lots of power for a very short time. Think about it guys, these SPL trucks running 40,000 watts or more, they are requiring this to get full (or presumably near full) excursion from these 'low xmax SPL subs'. They wouldn't be running 40 kilowatts if they could reach full cone excursion (at tuning) with 10k. If it takes that kinda power to push those 10mm xmax drivers (for example), what would it take to push an 06 XXX to its excursion limits under those conditions (at tuning with a sine wave)? It boggles the mind. Therefore at some point power absorbtion (heat dissipation really) becomes the most important factor in the SPL sub, and less importance is placed on potentially high xmax numbers.

Also energy is never lost just changes form, like heat, or sound waves. So if 900w extra is going to a woofer of the same linear travel I can't believe that all 900 is changing to heat and not making anymore sound than the speaker taking 100w to reach that linear travel.

Believe it or not, its quite true. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif That's the beauty of higher efficiency (in anything, not just speakers)... its getting something for nothing. Higher efficiency is getting more product for no more work, or getting the same product for less work. In this example, the product would be the output level of the speaker, and the work would be the amount of input watts. The rest is lost in motor inefficiency and suspension stiffness (friction).

I didn't bother to read the rest of the thread so please forgive me. Using that train of thought though would that mean the 06 XXX with its 4-5 inches of xmax result in better SQ?

xmax and SQ...
Each sub has an xmax. "Linear travel" is based off of distortion figures derived from the loss of BL as the voice coil leaves the gap. So lets compare two situations:

Sub A has a maximum linear travel (xmax) of 13mm. Sub B has an xmax of 32mm. Again, sealed same-alignment boxes to keep things even, same efficiency and input power... basically all other things being equal besides potential xmax. Now, both systems are moving their cones 12mm, output is approx the same. But, sub A is playing very near its excursion limits (and close to this distoriton threshhold) while sub B is not even close to its limits. In other words, sub A is working much harder than sub B to create the same output level, and thus is creating more distortion than sub B. So yes, xmax CAN affect SQ and distortion.

BTW, in case you haven't noticed, the 06 XXX has received some very positive SQ reviews.

 

[Pyro_By_Nature 5,000+ posts]

and i wanna come hear it when you get it since were both in NJ and im gonna kill you with SQ and SPL

Oh yeah you'll kill him in SQ alright, an ipod and stock speakers........I see you care a lot about how your music sounds //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

 

[Spooby 10+ year member]

what brand is dd

http://www.ddaudio.com

 

[snoopdan 5,000+ posts]

The efficiency is in cone excursion (what you are calling linear travel).
The physics (very very basic). A speaker creates sound by moving back and forth to create sound waves in the air. All other things being equal, the more the cone moves, the more air it displaces, the louder it is. That statement is based on same sub, same box, same install. That statement is NOT saying the sub whose cone moves more is always louder. If you compare different installs, other factors come into play...

As already stated in this thread, subs in ported boxes tend to have less cone motion than their sealed counterparts, yet get louder. Futher more, just looking at the ported box, you may note that as the frequency of the signal gets lower and lower, closer and closer to the enclosure's tuning point, cone motion goes lower and lower, yet output goes up. Defies logic and seemingly physics, right? The difference is in the enclosure, it also has an efficiency, which is based around its tuning frequency. A ported box is most efficient at or near its tuning freq, the further you deviate from it the less efficient the box this. What this means is, as that signal freq dips lower and cone motion decreases, direct output from the sub is decreasin but enclosure efficiency is going up even faster.... net result... less cone motion but still more over all ouput.

Now that that's settled, lets go back to subwoofer efficiency. Two different subs playing in sealed boxes with the same alignment (for simplicity). Each sub's cone is moving 20mm for example. Sub A moves this 20mm with 1,000 watts input power, while sub B does it with 100 watts input power... which is louder? They will be the same. Remember, the basic physics behind the loudness of the sound is by how much air each sub is displacing. If they are the same sized subs, and they both have the same cone excursion, they (in theory here) are moving the same amount of air, and thus will have the same output volume. So, squeak's point is if you can get the same cone motion from a more efficient sub with less power, why would you chose the less efficient route?

Less efficient means more electrical drain on the charging system, which means more voltage problems, which means less performance. At the very least you will be spending more money to stiffen your charging system to adequately power the less efficient driver, while not gaining any performance over the more efficient setup.

In SPL it becomes more about how much power the sub can absorb in short burps. Those SPL rigs are playing very near enclosure tuning, cone motion is at its least (the enclsoure is choking down on the down, dampening its cone motion greatly), xmax is less important than the simple ability to absorb lots and lots of power for a very short time. Think about it guys, these SPL trucks running 40,000 watts or more, they are requiring this to get full (or presumably near full) excursion from these 'low xmax SPL subs'. They wouldn't be running 40 kilowatts if they could reach full cone excursion (at tuning) with 10k. If it takes that kinda power to push those 10mm xmax drivers (for example), what would it take to push an 06 XXX to its excursion limits under those conditions (at tuning with a sine wave)? It boggles the mind. Therefore at some point power absorbtion (heat dissipation really) becomes the most important factor in the SPL sub, and less importance is placed on potentially high xmax numbers.

Believe it or not, its quite true. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif That's the beauty of higher efficiency (in anything, not just speakers)... its getting something for nothing. Higher efficiency is getting more product for no more work, or getting the same product for less work. In this example, the product would be the output level of the speaker, and the work would be the amount of input watts. The rest is lost in motor inefficiency and suspension stiffness (friction).

xmax and SQ...

Each sub has an xmax. "Linear travel" is based off of distortion figures derived from the loss of BL as the voice coil leaves the gap. So lets compare two situations:

Sub A has a maximum linear travel (xmax) of 13mm. Sub B has an xmax of 32mm. Again, sealed same-alignment boxes to keep things even, same efficiency and input power... basically all other things being equal besides potential xmax. Now, both systems are moving their cones 12mm, output is approx the same. But, sub A is playing very near its excursion limits (and close to this distoriton threshhold) while sub B is not even close to its limits. In other words, sub A is working much harder than sub B to create the same output level, and thus is creating more distortion than sub B. So yes, xmax CAN affect SQ and distortion.

BTW, in case you haven't noticed, the 06 XXX has received some very positive SQ reviews.

*sigh* I remember posting informative stuff like this at one time, but it seems the kids on here just dont care //content.invisioncic.com/y282845/emoticons/furious.gif.fc81ca146dbff91fede3ed290dbc4f4c.gif