Giving the RE XXX another Try *Pic*

[T3mpest 10+ year member]

Passes time here. Think of it this way. I get paid.... to make you pissed off. I know you're probably extremely sexually frustrated being a 36 year old virgin in all, but you really need to lay off the uptight pills homie. What are you doing discussing audio anyway? Don't you normally just go around correcting 16 year olds grammar on here most of the time?

guess your job doesnt' require any physics or engineers skills, heck science or math in general. Let me guess, your surfing the internet working at the abercrombie and fitch store in a mall somewhere? Don't let the boss catch you, you need that minimum wage to buy the next sub that someone decides "bangs hard".

 

[Towncar 10+ year member]

silly 09ers

 

[T3mpest 10+ year member]

silly 09ers

silly 09'ers with 5k posts is more like it. If your going to be ignorant be quiet too!

 

[MmatsDude 10+ year member]

t3mpest is beasting the thread

 

[hornedfrog1985 5,000+ posts]

Hilarious, you guys bust out your calculators to tell 80 inches, and toxic tuan that they must not being doing it right because you have t/s parameters to say so.... LOL

 

[Papermaker85 5,000+ posts]

so you see where im going with the fact mms/bl affects fr?

high qes, low fs drivers just are going to respond like a low q high fs driver..

example 1..

take the FI q and the fi bl...

at a glance the BL has a higher 1w1m rating, from the higher fs and lower Q.. both require very different alignments but can be used in a wide range of alignments.. one would think the low q high fs design will be louder in small high tuned boxes.. fact is the q is louder up untill around 4 cubes, wherein its dampning. above tuning isn't adequate.. aka it becomes critically underdamped.. high frequency extesion/output is compromised, now the bl in under 3.5 is critically overdamped and low frequency extesion/output is compromised.. the underdamped alignment is directly affected by the affect of inertia.. i think of it like acoustic inductance when underdamped and acoustic capaitance when overdamped..

some speakers by design just lack the dampening, motor strength and current carring capabilities to reproduce...

 

[T3mpest 10+ year member]

so you see where im going with the fact mms/bl affects fr?high qes, low fs drivers just are going to respond like a low q high fs driver..

example 1..

take the FI q and the fi bl...

at a glance the BL has a higher 1w1m rating, from the higher fs and lower Q.. both require very different alignments but can be used in a wide range of alignments.. one would think the low q high fs design will be louder in small high tuned boxes.. fact is the q is louder up untill around 4 cubes, wherein its dampning. above tuning isn't adequate.. aka it becomes critically underdamped.. high frequency extesion/output is compromised, now the bl in under 3.5 is critically overdamped and low frequency extesion/output is compromised.. the underdamped alignment is directly affected by the affect of inertia.. i think of it like acoustic inductance when underdamped and acoustic capaitance when overdamped..

some speakers by design just lack the dampening, motor strength and current carring capabilities to reproduce...

Yeah i get where you going with it. I just feel that if someone is complaining that their sub drops off like a stone over 60hz and they've tried multiple boxes that inducantance is the first place they should look. Within the subbass region however damping or lack thereof will always be your primary concern when looking at the frequency response. Certainly from 60hz and down though inductance shouldn't be an issue with an decently designed driver.

 

[Papermaker85 5,000+ posts]

Hilarious, you guys bust out your calculators to tell 80 inches, and toxic tuan that they must not being doing it right because you have t/s parameters to say so.... LOL

read and you will understand..

the XXX is made to be sealed in large boxes for low frequency extention and output.. if the decided to use it for a ground pounder they would use a lower qe higher fs design.. like i mentioned eariler you can compensate for mms with stiffer spiders and more b/l.. it just takes more current..

also on damping factor matching input to output impedance can be controlled.. look at the arc/lunar/tru amps.. fact is higher B higher L and more current all lead to feedback and opposition in reference to returning to rest position, not just the lad lead we know of as inductance.. reactance is the result of inductances affect on frequency..

simply put inductive reactance increases impedance as frequency increases while capaitance reactance is opposite....

 

[Toxic Tuan 10+ year member]

The newer XXX is a very nice sub, just not a nice sub for what most people use subwoofers for on this forum. The high moving mass doesn't affect transient response, transient response is mostly dicatated by enclosure design and indutance. The sub is also very good a getting loud, if we are concerned with 15hz instead of 35 and take away the space constraints in most vehicles. It's a good HT sub for both movies and music, it just doesn't lend itself to a car audio install very well, especially not on a forum where "groundpounding" is the norm. In a car audio install I 'd use a big sealed box and then take away whatever low end you don't need via eq. They take alot of power and have alot of excursion capablity, you can contour the response almost anyway you want to, which is nice.

T3mpest, this is not directed at you,

You're right high moving mass doesn't effect the transient response directly. Transient response is dependently controlled by the enclosure. With enclosure designs, the lower the moving mass, the lower the transient response in most cases. The other factor in lowering the transient response is a high motor strength. The combination of high motor strength and a low mms allows for the extreme accuracy in a ported type enclosure. I guess you can say they're indirectly related though.

When I first started doing enclosure designs, I followed strictly with Dan Wiggin's papers and I'm quite aware of Stereo Integrity's documentations. However, I've found their theories no longer applicable with some of my newer designs.

Remember years ago, many said that a ported enclosure can never be louder than a ported enclosure. Time went by and it was de-bunked quite quickly. Next, the new idea: ported enclosures can't sound as good or be as accurate as a sealed enclosure. I've been saying this for years: "a ported enclosure will always have a better transient response than a sealed enclosure." I was challenged by many by of this, but I've always stood my grounds. My designs aren't based on traditional theories. The more I learned about acoustics in a vehicle, the more I've realized we're far from understanding the fundamentals. Recently, the person that won the IASCA regionals had a ported enclosure with 2 15" DD9515's. He won in 2 categories with a perfect score in sub bass. I designed and built this enclosure. Many people were shocked by this. Let's just say that I've figured out a decent formula but it still requires the concentration of 2 factors: low mms and high motor strength. In real world application: what is the point of design a perfect subwoofer in theory, but when applied with an enclosure doesn't quite work. Many manufacturers need to reverse engineer and design the subwoofer with the enclosure as the main "real world" factor prior to anything else.

While I understand and appreciate theories for it is the fundamentals that has taught me foundations. But, with what I do...these theories are being broken everyday. My good friend Pete from PWK Designs will be the first to tell you this. In my books, he's one of the best enclosure designers out there. Pete has a particle collision engine theory and calculator that is the most accurate and makes theoretical softwares such as Bass Box Pro or Leap look like grade school.

There's a lot more we need to learn and it takes controversial issues and debates to get new ideas or to re-enforce the old ones.

Tuan

 

[T3mpest 10+ year member]

T3mpest, this is not directed at you,
You're right high moving mass doesn't effect the transient response directly. Transient response is dependently controlled by the enclosure. With enclosure designs, the lower the moving mass, the lower the transient response in most cases. The other factor in lowering the transient response is a high motor strength. The combination of high motor strength and a low mms allows for the extreme accuracy in a ported type enclosure. I guess you can say they're indirectly related though.

When I first started doing enclosure designs, I followed strictly with Dan Wiggin's papers and I'm quite aware of Stereo Integrity's documentations. However, I've found their theories no longer applicable with some of my newer designs.

Remember years ago, many said that a ported enclosure can never be louder than a ported enclosure. Time went by and it was de-bunked quite quickly. Next, the new idea: ported enclosures can't sound as good or be as accurate as a sealed enclosure. I've been saying this for years: "a ported enclosure will always have a better transient response than a sealed enclosure." I was challenged by many by of this, but I've always stood my grounds. My designs aren't based on traditional theories. The more I learned about acoustics in a vehicle, the more I've realized we're far from understanding the fundamentals. Recently, the person that won the IASCA regionals had a ported enclosure with 2 15" DD9515's. He won in 2 categories with a perfect score in sub bass. I designed and built this enclosure. Many people were shocked by this. Let's just say that I've figured out a decent formula but it still requires the concentration of 2 factors: low mms and high motor strength. In real world application: what is the point of design a perfect subwoofer in theory, but when applied with an enclosure doesn't quite work. Many manufacturers need to reverse engineer and design the subwoofer with the enclosure as the main "real world" factor prior to anything else.

While I understand and appreciate theories for it is the fundamentals that has taught me foundations. But, with what I do...these theories are being broken everyday. My good friend Pete from PWK Designs will be the first to tell you this. In my books, he's one of the best enclosure designers out there. Pete has a particle collision engine theory and calculator that is the most accurate and makes theoretical softwares such as Bass Box Pro or Leap look like grade school.

There's a lot more we need to learn and it takes controversial issues and debates to get new ideas or to re-enforce the old ones.

Tuan

How can you design the woofer around the box without knowing what box the person will be using? Different vehicles have different transfer functions and not everyone wants the same FR out of their subwoofer. The only company that I know does anything like that is DD as people generally want loud when they choose DD subwoofers. I'm quite aware BigRed uses DD subwoofers, but honestly, I'd say his perfect scores are mostly a reflection on the fact that his midbass to subbass transition is good as that's pretty much all they judge at SQ comps. If the bass isn't behind you and it seems to hit the lowest notes then your good to go. Kicker made plenty of SQ cars too for this very reason. Anyway you should elaborate on the better transient response as I don't see how having two radiators, both a a speaker and port that aren't even in complete phase would EVER have better transient response. You added more variables to a non-linear system.

Anyway Pete is a great designer, I know he uses Akabak, which is a very poweful design software, albeit hard to use for most. I'd also agree Ported enclosures are better for SQ in a car. Transient response in a car is a moot point since the subs are behind you reflecting 8000x times in a tiny car where almost every frequency is simply pressure mode as the waveform has no room to develop before reflecting. The extra couple m/s isn't going to matter a bit. However, when you use a ported enclosure you can cut down on excursion dramatically as well as use less amplifer power. Once you have more ouput than you can ever need to can shape the frequency response anyway you want without worrying about distortion. I'd rather do that than shoehorn a sub into a tiny box and get frequency response that is relatively close right off the bat, but have terrible dynamics as a result. Anyway since had a hand in it, what tuning frequency and box size is he using when he's competing, I was always curious?

Anyway most research on transient response shows that anything below 18m/s in subwoofer territory is ok. That's in a perfect room with good hearing, go into a car an any value you would get in even a decent enclosure is going to be ok. I doubt in the real world anyone can even tell, the better "transient response" that people think they hear when using a sealed enclosure is mostly due to a better frequency response, which a ported enclosure can very well do the same thing with even better dynamics!

 

[Kryptonitewhite 10+ year member]

The newer XXX is a very nice sub, just not a nice sub for what most people use subwoofers for on this forum. The high moving mass doesn't affect transient response, transient response is mostly dicatated by enclosure design and indutance. The sub is also very good a getting loud, if we are concerned with 15hz instead of 35 and take away the space constraints in most vehicles. It's a good HT sub for both movies and music, it just doesn't lend itself to a car audio install very well, especially not on a forum where "groundpounding" is the norm. In a car audio install I 'd use a big sealed box and then take away whatever low end you don't need via eq. They take alot of power and have alot of excursion capablity, you can contour the response almost anyway you want to, which is nice.

didnt think Id hear a good responce to this... but there it is

Cone velocity does not dictate frequency. It does however affect output as its related to excursion for a given frequency. If mass affected velocity which affect frequency, then two different subs fed a 50hz signal (for example) would output two different frequencies based on their mms difference, which we know is not the case.
In other words, both subs would still vibrate at 50 cycles, but the mms would affect velocity which would affect ability for cone travel (excursion) for that 50 cycles per second.

hah, I used that scenario myself several times back in the day. "so if an 18" is slower than a 10", does that mean that the 10" actually plays a 50Hz tone when it is given a 40Hz signal? Does the 18" actually play a 30Hz tone when given a 40Hz signal?"

 

[Toxic Tuan 10+ year member]

How can you design the woofer around the box without knowing what box the person will be using? Different vehicles have different transfer functions and not everyone wants the same FR out of their subwoofer. The only company that I know does anything like that is DD as people generally want loud when they choose DD subwoofers. I'm quite aware BigRed uses DD subwoofers, but honestly, I'd say his perfect scores are mostly a reflection on the fact that his midbass to subbass transition is good as that's pretty much all they judge at SQ comps. If the bass isn't behind you and it seems to hit the lowest notes then your good to go. Kicker made plenty of SQ cars too for this very reason. Anyway you should elaborate on the better transient response as I don't see how having two radiators, both a a speaker and port that aren't even in complete phase would EVER have better transient response. You added more variables to a non-linear system.
Anyway Pete is a great designer, I know he uses Akabak, which is a very poweful design software, albeit hard to use for most. I'd also agree Ported enclosures are better for SQ in a car. Transient response in a car is a moot point since the subs are behind you reflecting 8000x times in a tiny car where almost every frequency is simply pressure mode as the waveform has no room to develop before reflecting. The extra couple m/s isn't going to matter a bit. However, when you use a ported enclosure you can cut down on excursion dramatically as well as use less amplifer power. Once you have more ouput than you can ever need to can shape the frequency response anyway you want without worrying about distortion. I'd rather do that than shoehorn a sub into a tiny box and get frequency response that is relatively close right off the bat, but have terrible dynamics as a result. Anyway since had a hand in it, what tuning frequency and box size is he using when he's competing, I was always curious?

Anyway most research on transient response shows that anything below 18m/s in subwoofer territory is ok. That's in a perfect room with good hearing, go into a car an any value you would get in even a decent enclosure is going to be ok. I doubt in the real world anyone can even tell, the better "transient response" that people think they hear when using a sealed enclosure is mostly due to a better frequency response, which a ported enclosure can very well do the same thing with even better dynamics!

You're right on that. DD is the only company so far that has gotten it right. However, DD's subwoofers aren't designed to be loud. They're designed to be sound quality drivers first which happens to be efficient and can handle a ton of power due to demand.

If you've ever listened to Jim's truck way before that setup beforethe mid's were in...they're quite amazing. That enclosure has been in his car for over 3 years with what I considered as old enclosure technology. I've designed many high end systems, particularly in the subwoofer range and that's where I specialize at. I'd be the first to admit that I'm nowhere near the best with an SQ install...but I have many high end customers that goes to me after their install has been complete for a subwoofer setup. In most of these setups, the sub bass plays up to 60 or 80 hz even. The number one thing people tend to do is limit themselves with the maximum allowed space for the subwoofer. By doing so, they've eliminated all potentials of the enclosure and never allows the subwoofer a fair chance. You know how we always say "it's all in the install" or "install is 90%." I'd say the enclosure is 75% of the bass. I've owned over 400 subwoofer, I sure hope I've gotten something right. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

"both a a speaker and port that aren't even in complete phase would EVER have better transient response"

But it can be in phase or relative close so that one cannot distinguish the different. It can actually be measured also. When I first started car audio, I thought otherwise. One day I decided to do some experiments. I took a few enclosures to CSUF and placed Pito tubes all across the enclosure and the port to measure pressure deviations and velocity profiles. That has enlightened me to new realms never been discussed in the audio world before. From there, I played with the wind tunnel experiments. Immediately I realized the environment played a huge difference. The enclosure design is complete dependent upon the environment. I've written some articles before in regards to this. Ex: sometimes a customer asks me to design system that peaks aroudn 35 hz, my solution is designing the enclosure tuned to 45 hz and have the cabin/vehicle transfer function complete the rest. The goal was achieved. The same goes with my CRX that won the finals. There is a whole story with that in regards to amplifier that nobody thought would work...but it did, and I knew it from day one.

With Jim's car, the enclosure was tuned to 38 hz which played linear to 34 in actual response. From there, it was later lowered to right around 30-31 hz by down sizing the port.

In your last statement, I couldn't agree more...Ported Type Enclosures!

Tuan

 

[T3mpest 10+ year member]

You're right on that. DD is the only company so far that has gotten it right. However, DD's subwoofers aren't designed to be loud. They're designed to be sound quality drivers first which happens to be efficient and can handle a ton of power due to demand.
If you've ever listened to Jim's truck way before that setup beforethe mid's were in...they're quite amazing. That enclosure has been in his car for over 3 years with what I considered as old enclosure technology. I've designed many high end systems, particularly in the subwoofer range and that's where I specialize at. I'd be the first to admit that I'm nowhere near the best with an SQ install...but I have many high end customers that goes to me after their install has been complete for a subwoofer setup. In most of these setups, the sub bass plays up to 60 or 80 hz even. The number one thing people tend to do is limit themselves with the maximum allowed space for the subwoofer. By doing so, they've eliminated all potentials of the enclosure and never allows the subwoofer a fair chance. You know how we always say "it's all in the install" or "install is 90%." I'd say the enclosure is 75% of the bass. I've owned over 400 subwoofer, I sure hope I've gotten something right. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

"both a a speaker and port that aren't even in complete phase would EVER have better transient response"

But it can be in phase or relative close so that one cannot distinguish the different. It can actually be measured also. When I first started car audio, I thought otherwise. One day I decided to do some experiments. I took a few enclosures to CSUF and placed Pito tubes all across the enclosure and the port to measure pressure deviations and velocity profiles. That has enlightened me to new realms never been discussed in the audio world before. From there, I played with the wind tunnel experiments. Immediately I realized the environment played a huge difference. The enclosure design is complete dependent upon the environment. I've written some articles before in regards to this. Ex: sometimes a customer asks me to design system that peaks aroudn 35 hz, my solution is designing the enclosure tuned to 45 hz and have the cabin/vehicle transfer function complete the rest. The goal was achieved. The same goes with my CRX that won the finals. There is a whole story with that in regards to amplifier that nobody thought would work...but it did, and I knew it from day one.

With Jim's car, the enclosure was tuned to 38 hz which played linear to 34 in actual response. From there, it was later lowered to right around 30-31 hz by down sizing the port.

In your last statement, I couldn't agree more...Ported Type Enclosures!

Tuan

By downizing the port you mean lowing tuning, or did you reduce the port area while keeping tuning constant? I'd assume the former, but just making sure. Environment does play a big role, PWK has a spot on their webpage where they show the same sub in the 3 different cars with wildly different frequency responces for each one. It's very true, unless you know your tranfer function or have had enough setups in your car to know what's lacking, simply picking a box and a tuning frequency is a shot in the dark. Any time I switch cars since I don't have an RTA I pick a sub and box combo I know very well how it sounds in my last car and listen to it in my new one. From there I have a good idea of what my cabin gain is like and can build a decently accurate ported box as a result. I do that when I install for friends too. I have a adire koda 10 I put in to test the waters so to speak. Once I know what the how the car responds I can build a nicer box, which isn't always as conventional as tuning to mid 30's.

 

[Toxic Tuan 10+ year member]

By downizing the port you mean lowing tuning, or did you reduce the port area while keeping tuning constant? I'd assume the former, but just making sure. Environment does play a big role, PWK has a spot on their webpage where they show the same sub in the 3 different cars with wildly different frequency responces for each one. It's very true, unless you know your tranfer function or have had enough setups in your car to know what's lacking, simply picking a box and a tuning frequency is a shot in the dark. Any time I switch cars since I don't have an RTA I pick a sub and box combo I know very well how it sounds in my last car and listen to it in my new one. From there I have a good idea of what my cabin gain is like and can build a decently accurate ported box as a result. I do that when I install for friends too. I have a adire koda 10 I put in to test the waters so to speak. Once I know what the how the car responds I can build a nicer box, which isn't always as conventional as tuning to mid 30's.

Yep, lower the tuning. That's awesome, the Koda is your reference sub. I have 3 reference subs that I use: low, mid and high Fs. It's helpful having a RTA around. Pete and I have gone a long way...especially Pete. I still remember the first day I met him when he visited me to have his car built. Now, he's a master at what he does and better than me in certain aspects. Yet, we all still have a lot to learn.

Tuan

 

[audioholic 5,000+ posts]

I know you're probably extremely sexually frustrated being a 36 year old virgin in all, but you really need to lay off the uptight pills homie. What are you doing discussing audio anyway? Don't you normally just go around correcting 16 year olds grammar on here most of the time?

Shush, the adults are talking.
Good thread Tempest, Tuan and papermaker. BTW Tempest, even a simple radio shack db meter can be utilized as a make-shift RTA for what you are wanting to accomplish, it just takes a bit more time than an actual RTA.