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Discussion Starter · #1 ·
LTD02,


You seem to be on this kick of implying that long throw Mal-X/ LMS/ SDX type subs only have an advantage over PA drivers on the very deepest bass below 25 or 20hz and that they can't "punch" in the upper bass, which IMHO is just not true. So let's discuss it.


I'd like to know which bass drivers you currently own, which you have owned and which ones you have direct personal experience with. I'd also like for you to explain where you believe this subjective "punch", "attack", "slam", or "tightness" whatever you wish to call it comes from. Obviously there are different tools for different jobs. If you wish to go into the high BL/ low MMS/QMS relationship again that is fine, but again, IMO it does not really tell the full story.


I'm sure that many other people have strong opinions here so please weigh in if you have one and address the questions above.
 

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Someone get the popcorn



Im very interested in a great discussion so I can learn more about this!!
 

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Quote:
Originally Posted by Ricci /forum/post/16913618


Yes get your popcorn gif ready. This should be a train wreck.

Maybe but I have been waiting for someone to put this stuff to bed so hopefully the train has some good info on it before it crashes
 

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Does it count if I post in this thread?
 

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Discussion Starter · #6 ·

Quote:
Originally Posted by LHD21 /forum/post/16913671


Does it count if I post in this thread?

By all means please do. I only directed the first post to LTD02 because he has been bringing this up in nearly every DIY bass thread he's been posting in lately, so I wanted to find out where he's coming from. I'm especially interested in the thoughts of people who have actual experience on both sides of the fence like I do. I'd like to see what people's opinions are and their reasons for them. This has been discussed a bunch of times already, but hey maybe we can learn something new.
 

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I think listening impressions are simply a matter of how the drivers are commonly used. A pro 15" may be crossed anywhere from 300 to 1.5K. A home sub seldom plays above 80 Hz. Punch and slam are generally in a frequency range well above where a home sub normally plays. So, you listen to a pro woofer and it is playing those slam frequencies. You listen to a home sub and it isn't playing those frequencies. It would be easy to incorrectly conclude that the home sub can't play up high and there's something wrong with it just because it isn't usually asked to do it.


All that said, not all home subs are comfortable playing up high. Low Le/Re, showing up as an impedance curve that doesn't rise too much at the high end, is a pretty good indication of the ability to do it. That and any obvious cone breakup showing up in the frequency response and impedance curves help define the HF limit. But those requirements apply to all drivers, not just home subs.
 

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Quote:
Originally Posted by Ricci /forum/post/16914109


By all means please do. I only directed the first post to LTD02 because he has been bringing this up in nearly every DIY bass thread he's been posting in lately, so I wanted to find out where he's coming from. I'm especially interested in the thoughts of people who have actual experience on both sides of the fence like I do. I'd like to see what people's opinions are and their reasons for them. This has been discussed a bunch of times already, but hey maybe we can learn something new.

I was joking due to half the forum thinking that LTD and I were the same person since our nicks are very similar. I quoted him in a thread yesterday that made a couple people do the RCA-Dog head twist for a minute.
 

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Ricci--maybe some insight can be gained by you and other GTG participants answering the question as to why the Danley TH-50 was so much more impressive than the other subs at the GTG. Was it just because it could go louder? Efficiency? Something else happening at equal db's??? I am very curious as to the siren song of the tapped horn!
 

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Discussion Starter · #10 ·

Quote:
Originally Posted by Fatawan /forum/post/16914416


Ricci--maybe some insight can be gained by you and other GTG participants answering the question as to why the Danley TH-50 was so much more impressive than the other subs at the GTG. Was it just because it could go louder? Efficiency? Something else happening at equal db's??? I am very curious as to the siren song of the tapped horn!

Surprise surprise! The TH50 uses a presumably high inductance, low efficiency, long throw, 28mm xmax, MTX 9515. Not a pro driver. It's all enclosure magic on that one. That was all brute output and efficiency at work there. That's a little bit of a different topic though...or is it?
 

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Quote:
Originally Posted by Warpdrv /forum/post/16914506


Good thread Ricci, been wondering about the comparisons myself, I'd like to see mark seaton stop by and post his thoughts, I think he'd have some good incite on this topic.

Mark would have a good opinion but John Janowitz from AE speakers is going to lots of knowledge. Kevin Haskins should be another good source for us.
 

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Quote:
Originally Posted by Ricci /forum/post/16914501


Surprise surprise! The TH50 uses a presumably high inductance, low efficiency, long throw, 28mm xmax, MTX 9515. Not a pro driver. It's all enclosure magic on that one. That was all brute output and efficiency at work there. That's a little bit of a different topic though...or is it?


does xmax need to be high for tight bass though? I thought it was all about the Mms/BL and damping stuff??
 

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I think everyone should know my opinion by now.


Your comparing apples to oranges though. You would need to equalize two systems so that their anechoic FR is the same before you could make a valid comparison. When you did, you would likely find that there is little to no difference at moderate power levels at higher frequencies. In the 1st octave the drivers are primarily limited by mechanical capability, the driver with higher mechanical capability will trump the same driver with less excursion.


The prosound woofer with a big coil and big power handling will likely perform better at sustained 80Hz levels though. The higher efficiency of a prosound driver (at the expense of bandwidth) will require significantly less power for the same SPL. It can be orders of magnitude lower and pro-sound drivers tend to be made with huge coils to begin with. They are designed around output @ higher frequencies where power is the limiting factor, not mechanical stroke of the driver. At really sustained high power levels in that situation, they make more sense than a big stroker of much lower efficiency.
 

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Quote:
Originally Posted by penngray /forum/post/16914525


does xmax need to be high for tight bass though? I thought it was all about the Mms/BL and damping stuff??

Hmm, xmax shouldn't effect anything. 10mm or 30mm, all the other parameters can be the same.


My only eroneous information I have is the TD15h's sound better for music crossed over at 150hz than the SDX-15. And that's in the same identical ~4ft sealed enclosure. For movies, the SDX-15 is better due to the increased Xmax which increases low end output.


QTC is different between the two drivers...Hmm.
 

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Discussion Starter · #16 ·
My personal opinion is that the driver itself has less of an effect than everyone thinks and does not dominate the results by itself it merely plays a part. The enclosure, the environment, the signal chain and everything else play a huge role. Even in a simple sealed box.


Obviously drivers like the Maelstrom X and a JBL 2242H are designed for much different goals but both are related to bass reproduction. My gut tells me that if you take both drivers: put them in a high quality enclosure of the same type of alignment that compliments their respective abilities, in the exact same system, in the exact same orientation and placement, restrict each of them to the exact same bandwidth that both drivers are comfortable with, let's say 35-100hz, EQ the total system FR of both to be as close to the same as possible, then level match them to within a gnat hair of equal and drive both to equal levels that are well within their comfort zone with low distortion. I don't think either will sound punchier or more dynamic, or any other descriptive term you'd like to use, more than the other. They will sound probably very, very close to the same. You might say that that comparison is silly and of course using different drivers, bandwidth's and enclosures is the whole point of using different drivers, and will result in different sonic signatures and you'd be right, but what it would also say is that most of the subjective terms that everyone throws around are much more related to the system FR, energy storage, listener/ environment interaction, and overall headroom and SPL levels than the fact that someone is using a pro style driver, or a hifi driver.


That's my story and i'm sticking with it, at least until someone convinces me otherwise.


EDIT: I hate long posts! Kevin beat me to it...
 

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I have been around a bit and listened to a bunch of different stuff, as well as own a few different bass drivers over the years.


My take from what I have experienced so far is that drivers that have a lot of motor strength as well as linearity sound a lot better at higher drive levels and excursions.


Pro drivers are typically tuned high, to keep excursion down ( in their linear range ) as well as have other benefits like tight mechanical clearance from the pole piece / gap plate to the coil.


This allows the coil to dissipate heat quickly, and helps out in the dynamics department. Larger enclosures than your typical home hi-fi drivers. In box impedance is often high, allowing greater damping factor as well as less average power across the coil. Often 10~db more sensitive than your home sub driver. Less average power = less heating, again better transient response.


Subwoofer drivers designed for home or car usage generally have larger gaps, and higher excursions. They may or may not suffer from issues like Bl linearity, suspension linearity, thermal constraints ( in the upper bass ), air spring non-linearity ( tiny box issues ) etc.


They are often designed for small boxes and boast high power handling capabilities. The reality is that there is only a handful of drivers that do well with high power continuously. Even then there can be issues. Amplifier headroom is limited with tiny boxes and low sensitivity drivers. Higher average power = more thermal compression. ( better drivers have good heat transfer abilities ) Generally more amperage across the coil than a pro driver ( lower in box impedance ), can lead to inductance modulation if steps are not taken to combat that.


Lots of steel in the gap as well as a magnetic circuit that is fully saturized helps out here.
 

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Quote:
Originally Posted by Ricci /forum/post/16914735


You might say that that comparison is silly and of course using different drivers, bandwidth's and enclosures is the whole point of using different drivers, and will result in different sonic signatures and you'd be right, but what it would also say is that most of the subjective terms that everyone throws around are much more related to the system FR, energy storage, listener/ environment interaction, and overall headroom and SPL levels than the fact that someone is using a pro style driver, or a hifi driver.


That's my story and i'm sticking with it, at least until someone convinces me otherwise.


.

Efficiency probably plays a huge role. If you start with a typical "set all speakers/subs to 75db", you don't at all account for efficiency. As you turn it up, an efficient pro-style driver will get much louder than your typical home theater speakers(more punch, more slam) unless you run efficient LCR's. Perhaps that is what some people get out of using higher efficiency drivers or enclosures like the TH-50's tapped horn. We should make some graphs of speaker output and another of sub output as the dial changes and see("we" meaning Vas).
 

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Discussion Starter · #19 ·
Good points about efficiency being key Mike, but here's the deal. What levels are we talking about here? If you are talking about serious power compression of 1-2db setting in on a Mal-x or TC2000 type of driver then I would submit that you are looking at peak levels well in excess of 110db in room already figuring a really low 85db sensitivity and figuring around 300w input or more on the peaks. This would lead me to believe that it is an SPL output headroom/system limitation/ IE running out of gas problem not necessarily a sound quality problem at normal volumes like 105db or less. Are we saying "hey my system doesn't have that punch I'm looking for at 125db, but it sounds just fine at 95db"?


What about the fact that people always say that their low tuned ported sub just doesn't have the kick they thought it would when we know that at most it lost 1 or 2db of maximum output up top if that much even. How do you guys feel about that?
 

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Quote:
Originally Posted by Ricci /forum/post/16913596


LTD02,


I'd like to know which bass drivers you currently own, which you have owned and which ones you have direct personal experience with. I'd also like for you to explain where you believe this subjective "punch", "attack", "slam", or "tightness" whatever you wish to call it comes from.


I'm sure that many other people have strong opinions here so please weigh in if you have one and address the questions above.

In technical terms it's called 2HD and nothing below 30Hz.



Bosso
 
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