is 2Hz/4Hz worth additional $600/$900???

[fuzz092888]

I'd daresay the nicest thing outside of sheer performance about the TSAD is the weight; the LMS Ultra is one the best 18" drivers on the market no doubt, but it's also a back breaker at >80lbs. Conversely, Josh pegged the TSAD ~30-35 pounds, and the complete Funk 18.0 weighs in at less than 100 pounds. I'd consider that a pretty cool feat considering that smaller, less capable subs like the SB13U, ULS-15, and F15HP are in the same ballpark.

I agree. That's the only knock I have against the LMS U drivers. The dual Opposed I built is unmovable as it sits. When I move I'll definitely be ditching the current cabinet and redesigning one with handles and wheels. The TSAD is definitely one heck of a driver to give that kind of performance down low while being so light. I would think the weight also contributes to its ability to sound better into the upper bass/lower midrange (at least according to ADTG).

 

[AcuDefTechGuy]

Yes, I do think my Funk 18.0 TSADv1 passive subs sound like high-end tower speaker bass (like Salon2), except a lot more powerful and punchy.

And my comment for the OP's question of whether 4Hz is worth $900?

I guess it depends on what is more important to you.

I used to own a $500 NHT SW2P 10" sub (80W amp). And that one little sub was able to shake my room's walls like a ragdoll for movies and music. And this sub was only capable of 25Hz.

When I owned the Rythmik 15" subs, I set the frequency to 28Hz, instead of 20Hz or below. Because that's what I care about.

So sure, music and movies may have frequencies even down to 10Hz. But for the most part, the majority of the bass sound is above 24Hz.

So my answer is no, 4Hz is not worth my $900.

But we all measure "worth" differently, don't we?

Like quality over quantity. It's great to have both, but if I could only have one, I would go with quality.

 

[shadyJ]

You can thank its Neodymium magnet for the light weight. I don't think the overall weight would have any effect on the sound quality though. The weight of the cone certainly will, and the sexy carbon fiber cone of the TSAD is bound to weight a lot less than the Aluminum cone of the LMS Ultra. That may account for it greater headroom in the mid and upper bass range and any differences that would be heard in that region.

 

[copmagnet82]

I've been looking at the graphs and it seems like with sealed subs, no matter what sub you get, anything below 30Hz will have a pretty big spike in THD.

As I said before, 1500X was scratched off the list and now I'm still trying to justify the size of the PB13-ultra.

After reading lsiberian's post in regards to bigger box in order to decrease THD in a sealed enclosure, I was actually seriously considering getting PB13-ultra and using it in a sealed mode depending on my mood, but then, after looking at the graphs, it essentially turns into a SB13-ultra in a bigger enclosure, although I would gain the flexibility of switching from sealed to ported design, but then again, I wonder if I'd actually ever be going back and forth between the two. I guess clean 20Hz is not really an option in a sealed design.

 

[copmagnet82]

So sure, music and movies may have frequencies even down to 10Hz. But for the most part, the majority of the bass sound is above 24Hz.

that's a very valid point

So my answer is no, 4Hz is not worth my $900.

But we all measure "worth" differently, don't we?

Like quality over quantity. It's great to have both, but if I could only have one, I would go with quality.

agreed

 

[kramskoi]

I've been looking at the graphs and it seems like with sealed subs, no matter what sub you get, anything below 30Hz will have a pretty big spike in THD.

As I said before, 1500X was scratched off the list and now I'm still trying to justify the size of the PB13-ultra.

After reading lsiberian's post in regards to bigger box in order to decrease THD in a sealed enclosure, I was actually seriously considering getting PB13-ultra and using it in a sealed mode depending on my mood, but then, after looking at the graphs, it essentially turns into a SB13-ultra in a bigger enclosure, although I would gain the flexibility of switching from sealed to ported design, but then again, I wonder if I'd actually ever be going back and forth between the two. I guess clean 20Hz is not really an option in a sealed design.

You are thinking small my friend. Think FTW-21 and HS-24, LMS 18". Even as stout as the Ultra driver is, its Sd is under 700 cm^2. Compare that to a FTW-21 that can move as far or farther, with a Sd of about 1640 cm^2 or the HS-24 at 2230 cm^2. The drivers simply have to get larger to get cleaner below 30Hz sealed. The larger the driver, the slower the rise in THD toward the bottom. Smaller drivers might get there with wide swinging motors but the rise in THD will be sharper and more pronounced simply because they are smaller. This is one of the main reasons why I don't think I will be returning to anything smaller than low qts. 21" drivers, even if it means using pro sound motors. There is a niche to be filled but so far no one seems to want to fill it.

You also have to remember that THD will be lower in-room, especially if the room is on the small side with appreciable room gain. Finally, too many small sealed subs attempt to play flat too low, thereby turning their FR into something akin to a vented sub, which prematurely elevates THD. Sealed really is more about gradual, predictable roll offs and proper coupling with the room.

Just a note of what is possible as far as THD (3x15"):

 

[copmagnet82]

You are thinking small my friend.

I have to... I got a wife

The drivers simply have to get larger to get cleaner below 30Hz sealed.

1500X is technically larger then SB13, but didn't you say before that you were pretty sure that SB13 would have less THD? ...or is it sort of like splitting hair at that size and power, although SB13 has almost twice the RMS and more then twice the peak power of the 1500X

 

[kramskoi]

I have to... I got a wife


1500X is technically larger then SB13, but didn't you say before that you were pretty sure that SB13 would have less THD? ...or is it sort of like splitting hair at that size and power, although SB13 has almost twice the RMS and more then twice the peak power of the 1500X

Real short...the pb13 in sealed mode can match the Dynamo...97 dB at 20 Hz iirc. The Dynamo can get you more at 12 Hz but you will never hear it because between 12 - 24 Hz there is something of about a 24 - 30 dB of roll off due to highpassing below 20Hz. 16Hz is a wash but still the roll off is steeper than the pb13 sealed. The Sd difference is about 675 to 825, so the 13.5 inch Ultra driver, in a more optimized package, i.e. the SB-13, might put in a slightly better performance than in a less than optimal vented cabinet with simple port plugs. I think you will agree that the Ultra driver is just better and that makes all the difference. The Dynamo is simply designed to be flat to 20Hz and everything else is cast away, including THD, roll off and elevated group delay. The SB13 on the other hand, is designed to take better advantage of all aspects of a sealed design.

Yes, the drivers do have to get larger. Even a 13.5 inch Ultra driver would be no match for an 18" LMS...no match because its xmax advantage would be fully negated and it would suffer because of its much smaller Sd (almost 1/2 the size). The LMS will lose control slowly and gracefully, the Ultra, not so much. For every 2mm the LMS moves, the Ultra would have to move roughly 4mm to match Vd requirements.