AVS Forum banner
1 - 20 of 25 Posts

· Registered
Joined
·
8 Posts
Discussion Starter · #1 ·
So i'm looking to build a sub for a pretty much equal share in usage between music and movies.
I'm really after the capability to go real low and loud, but i'm afraid that ill give up SQ for when i want to listen to music. Granted most of that music is built for low end anyways, i do like to switch it up. SQ is important to me!

I'm chasing a 15'' driver to fit into an old sealed box i made, it has 1 inch thick and insulated MDF walls and has a volume of about 128l or 4.5ft3. I am also looking for a new amp to buy which will suite the driver and im looking between the 1500wrms and 3000wrms range. The lounge room isn't particularly large so it doesn't have to fill a 'Huge' Space.
To put it simply i'm really after something to perform on par with a SVS PB 16 ultra at about half the cost, (obviously with less bells and whistles). But id like the performance to be similar if its at all possible.

I've done some looking among the mass of subs and have found a few, which should be taken with a grain of salt because i really cant quite use the parameters enough to get a decent understanding in regards to what i want.

-Fi CarAudio Q15
-HTS 15mkii
-Sundown Audio X v.2 15''
- B&C 15DS115

anyways sorry if its a tad ambiguous, there is just a lot of information its a tad overwhelming.

p.s, another quick question in regards to Bl, as i understand Bl is the Magnetic Strength of the motor and is one of the factors that determines cone control, and that a higher bl generally means more theoretical control and therefore better Sq; So why is it that a large number of high end SQL subs seem to have Bl's of under 15? #

Thanks guys.
 

· Registered
Joined
·
554 Posts

· Registered
Joined
·
8 Posts
Discussion Starter · #3 ·
yes, the STW was the first sub on my list actually, until i came across the discussion on the AVS forums regarding its large Xmax claims and found quite a few people had negative opinions about it, and then considering that it need an awful lot of power for a half decent output. I also saw on that discussion the post about the HTS, and how on paper at least it out performed the STW in almost every aspect, so i dismissed the STW out of fear it wouldnt have enough output to be decent for movies. but if anyone want to say otherwise having heard the STW please do say.

At the moment the HTS is my favourite, the only reason i haven't pulled the trigger on it is because i was unsure if because its mainly a home theatre sub, that it would be sloppy and lack luster for fast music. would this likely be the case, or am i over thinking it far too much?

thanks for the reply btw.
 

· Registered
Joined
·
464 Posts
yes, the STW was the first sub on my list actually, until i came across the discussion on the AVS forums regarding its large Xmax claims and found quite a few people had negative opinions about it, and then considering that it need an awful lot of power for a half decent output. I also saw on that discussion the post about the HTS, and how on paper at least it out performed the STW in almost every aspect, so i dismissed the STW out of fear it wouldnt have enough output to be decent for movies. but if anyone want to say otherwise having heard the STW please do say.



At the moment the HTS is my favourite, the only reason i haven't pulled the trigger on it is because i was unsure if because its mainly a home theatre sub, that it would be sloppy and lack luster for fast music. would this likely be the case, or am i over thinking it far too much?



thanks for the reply btw.


Look very closely at the B&C 15DS115 if you have to stay with a 15”. But wood is cheap and you could buy a LaVoce 21” and a Behringer 3000D and have the best of both worlds... digs deep and insanely fast response. On sale at Parts Express less than 376. Just saying...
 

· Registered
Joined
·
5,338 Posts
I would start by looking for an JBL W15GTi “car” sub. That’s perfect volume for them. They have a very smart motor design and I think they’re still better than most of the stuff available. Don’t let the “car” label fool you. They’re closely related to JBL Pro flagship equipment.

The Fi is an old-fashioned, third rate driver. Long coil, no shorting rings, no thanks. I don’t know what the HTS is. The Sundown seems like a reasonable modern driver. Is the box a bit big for the B&C?
 

· Registered
Joined
·
12,700 Posts
I thought once you started getting above a 15'' driver, SQ started to go down as cone control was harder to achieve with such a big surface area?
No.
Excursion and Power causes SQ to decrease (or conversely: distortion to increase.)
Smaller cones needing more Excursion and Power for a given SPL, and are therefore are more distorted.

For bass frequencies, it's all about displacement.

It takes about ~32watts to push 32 18's to ~1mm, and it takes about ~3200watts to push 1 18 to ~32mm's; and both are the same SPL! ;)

The single cone distorting and farting and melting in minutes/seconds,
and the large array having bass-for-days with near-zero distortion and coil-heat.

The array isn't even trying yet...
What happens when the 32 18's goes to 10mm's? (EXACTLY! ;))

The same can be applied for a subwoofer driver of any size. The larger array of them always wins (by miles...)

18's are so popular because they have a good ratio of cone-area to price, or boom-per-dollar.

The SVS being a 16" has the advantage over any single 15 or smaller sub.
My rule of thumb is 1 18 for every 1000cuft of room. (If you can do more, then do it...)

I understand that WAF, space-constraints and budgets plays into it for many people; but that doesn't change the requirements or the physics of it.
 

· Registered
Joined
·
554 Posts
I would start by looking for an JBL W15GTi “car” sub. That’s perfect volume for them. They have a very smart motor design and I think they’re still better than most of the stuff available. Don’t let the “car” label fool you. They’re closely related to JBL Pro flagship equipment.
Now that's an excellent choice! I had a W12GTi in my own car and hooked it up in the house from time to time years ago. Detailed, Clean, and controlled bass are what these are about.


My bud Anthony had two W1515GTi in his sound quality vehicle mounted infinite baffle. The bass was awesome, clean, and full to say the least.



 

· Registered
Joined
·
12,700 Posts
That said:
There are limits, of course...

It's not practical to extract 20hz out of 1000 1" tweeters, or 500hz from a 64" woofer.
That is where arrays of smaller drivers comes into play.

Generally in a residential setting, 1 Tweeter, 1 Mid is absolutely sufficient for coving 300hz to 30khz entirely; and then a boat-load of woofers and subwoofers for covering 30-300hz and 1-30hz (because of the displacement-requirement and low-distortion @ high-spl requirement, and because our ears are additionally insensitive to such frequencies.)

Also: Having a lot of woofers and subwoofers helps avoid room-nulls (i.e. a smooth frequency response at all seats.)
It also helps reduce power, heat, excursion and distortion...
win-win

The only real downside is: space and cost.
 

· Registered
Joined
·
5,216 Posts
No.
Excursion and Power causes SQ to decrease (or conversely: distortion to increase.)
Smaller cones needing more Excursion and Power for a given SPL, and are therefore are more distorted.

For bass frequencies, it's all about displacement.

It takes about ~32watts to push 32 18's to ~1mm, and it takes about ~3200watts to push 1 18 to ~32mm's; and both are the same SPL! ;)

The single cone distorting and farting and melting in minutes/seconds,
and the large array having bass-for-days with near-zero distortion and coil-heat.

The array isn't even trying yet...
What happens when the 32 18's goes to 10mm's? (EXACTLY! ;))

The same can be applied for a subwoofer driver of any size. The larger array of them always wins (by miles...)

18's are so popular because they have a good ratio of cone-area to price, or boom-per-dollar.

The SVS being a 16" has the advantage over any single 15 or smaller sub.
My rule of thumb is 1 18 for every 1000cuft of room. (If you can do more, then do it...)

I understand that WAF, space-constraints and budgets plays into it for many people; but that doesn't change the requirements or the physics of it.
So what you are saying is to fill the room with many smaller subs rather than one or 2 large ones ?


I just did a quick search for the JBL W15GTi and the first one I found is local to me here in Western Australia - but it has been modified to supposedly make it better.
Would this be a good choice : https://speakerrestore.com.au/product/jbl-w15gti-15inch-sub/ or still better to go with multiple smaller 12s or 10s or multiple less capable 15s ?
 

· Registered
Joined
·
8 Posts
Discussion Starter · #11 ·
I thought once you started getting above a 15'' driver, SQ started to go down as cone control was harder to achieve with such a big surface area?
No.
Excursion and Power causes SQ to decrease (or conversely: distortion to increase.)
Smaller cones needing more Excursion and Power for a given SPL, and are therefore are more distorted.

For bass frequencies, it's all about displacement.

It takes about ~32watts to push 32 18's to ~1mm, and it takes about ~3200watts to push 1 18 to ~32mm's; and both are the same SPL! /forum/images/smilies/wink.gif

The single cone distorting and farting and melting in minutes/seconds,
and the large array having bass-for-days with near-zero distortion and coil-heat.

The array isn't even trying yet...
What happens when the 32 18's goes to 10mm's? (EXACTLY! /forum/images/smilies/wink.gif)

The same can be applied for a subwoofer driver of any size. The larger array of them always wins (by miles...)

18's are so popular because they have a good ratio of cone-area to price, or boom-per-dollar.

The SVS being a 16" has the advantage over any single 15 or smaller sub.
My rule of thumb is 1 18 for every 1000cuft of room. (If you can do more, then do it...)

I understand that WAF, space-constraints and budgets plays into it for many people; but that doesn't change the requirements or the physics of it.
Awesome explanation, clears up a lot!
 

· Registered
Joined
·
8 Posts
Discussion Starter · #12 ·
I would start by looking for an JBL W15GTi “car” sub. That’️s perfect volume for them. They have a very smart motor design and I think they’️re still better than most of the stuff available. Don’️t let the “car” label fool you. They’️re closely related to JBL Pro flagship equipment.

The Fi is an old-fashioned, third rate driver. Long coil, no shorting rings, no thanks. I don’️t know what the HTS is. The Sundown seems like a reasonable modern driver. Is the box a bit big for the B&C?
Thanks for the sub recommendation I'll be sure to check it out!
 

· Registered
Joined
·
8 Posts
Discussion Starter · #13 ·
No.
Excursion and Power causes SQ to decrease (or conversely: distortion to increase.)
Smaller cones needing more Excursion and Power for a given SPL, and are therefore are more distorted.

For bass frequencies, it's all about displacement.

It takes about ~32watts to push 32 18's to ~1mm, and it takes about ~3200watts to push 1 18 to ~32mm's; and both are the same SPL! /forum/images/smilies/wink.gif

The single cone distorting and farting and melting in minutes/seconds,
and the large array having bass-for-days with near-zero distortion and coil-heat.

The array isn't even trying yet...
What happens when the 32 18's goes to 10mm's? (EXACTLY! /forum/images/smilies/wink.gif)

The same can be applied for a subwoofer driver of any size. The larger array of them always wins (by miles...)

18's are so popular because they have a good ratio of cone-area to price, or boom-per-dollar.

The SVS being a 16" has the advantage over any single 15 or smaller sub.
My rule of thumb is 1 18 for every 1000cuft of room. (If you can do more, then do it...)

I understand that WAF, space-constraints and budgets plays into it for many people; but that doesn't change the requirements or the physics of it.
So what you are saying is to fill the room with many smaller subs rather than one or 2 large ones ?


I just did a quick search for the JBL W15GTi and the first one I found is local to me here in Western Australia - but it has been modified to supposedly make it better.
Would this be a good choice : https://speakerrestore.com.au/product/jbl-w15gti-15inch-sub/ or still better to go with multiple smaller 12s or 10s or multiple less capable 15s ?
I'd also like to know this, an example I can think of is the extremely high end and pricey paradigm sub 2.

Why have they gone with 6 10" drivers? Is there good reasoning behind this vs say 2 18" drivers which would have very similar cone surface area?
 

· Registered
Joined
·
12,700 Posts
One does have to be careful of box leaks. That said, the SPL is often so high by that point that you'd never notice.

Here is the impedance and FR of my SAB-24 nearfield.
It has a 5inch voicecoil that is at least 4inches in length and at least 2 layers thick, is a LOT of copper surround by a LOT of metal.

Of course it would be smoother if I had time-gated it and measured it outside, instead of in a room with no gating.



Not bad for a $250 driver, in a way-too-small 7cuft box... :p

Databass shows many large drivers extending to at least 200hz.
https://data-bass.com/#/systems

Anything higher than ~50hz is a woofer not a subwoofer, and >300hz is definitely mid-driver territory.

With a bit of EQ and an FP amplifier, it easily extends to single digits (especially if you were to put it in the +20cuft box that it wants/needs.)

The FP14k and 20k is half-power at 2.5hz based on voltage rolloff (-3db), maybe slightly less given the inefficiency of such low frequencies with real-world applied power into a load, then factor in mic-rolloff and soundcard-In/Out rolloff and it is amazing it is still this flat...

With 104mm of xmech it has LOTS of displacement and headroom.

I can't/didn't want holes in my walls so IB was a go-no, and that many ported subs would be WAY too much box volume consumed. I chose 7cuft sealed because then I can fit 32 subwoofers in my room.

I just have to add 5 more 24's to my system and them I'm calling it "enough bass", for this room... :p
 

Attachments

· Registered
Joined
·
4,085 Posts
I'd also like to know this, an example I can think of is the extremely high end and pricey paradigm sub 2.

Why have they gone with 6 10" drivers? Is there good reasoning behind this vs say 2 18" drivers which would have very similar cone surface area?
Let's do the math!

Say we will compare six Dayton Audio Ultimax 10 inch subs VS two Ultimax 18's--we will just worry about how much air they can pump since down low is what you are concerned with.

Subs are air pumps, it is bore X stroke just like in engines--this will give you liters of air the thing can move. (Plenty of other factors but you'll get the idea.

Bore (Sd) for the 18" is 1219cm2 while the bore of the 10 is 328cm2 Basic division indicates it will take 3.7 tens to equal the surface area of the 18.

Stroke (Xmax X 2) for the 18 is 44mm peak to peak and the 10 is shorter at 38mm peak to peak

Bore X stroke or 1219 X 44 for the 18 and 328 x 38 for the 10 = 5.36 liters for the 18 and 1.25 liters for the 10

Two 18's would displace 10.72 liters of air while six of the 10's would give you 9 liters of air displacement. If you wanted to duplicate a pair of 18's, it would be better to use eight 10's instead of six of them.

There are other factors, efficiency higher up in frequency VS efficiency lower in frequency, the ability of 18's go be tuned lower than 10's and so on but you get the idea.

So why would Paradigm build a sub with six 10's because a pair of 18's would offer better performance? Simple, because it was not built for performance! It was built to be different, a "halo product", a hexagon instead of a box or cylinder--a different spin that looks cool. There is nothing wrong with that, plenty of speakers and subs give up performance for looks, style, size and so on. Charging 10 grand for it makes it obvious it is more a "lifestyle" product where looks, style, uniquness and that sort of thing play out. Rather complex way to do it so that costs money, at 10 grand Paradigm probably does not expect to sell many of them--but that is not the point of a halo product. Most audio companies have done that long before any of us were born--plenty of people don't mind that, explains such things like a $15,000 purse or a $20K mechanical watch--it's not about holding your wallet and lip balm or knowing what time it is.

Some consumers actually believe that if something cost more, it is better! That's what TV, radio, advertising and everything else have been telling you since you were born. This is why you become an "educated consumer" and decide how much you wish to spend for looks, finish, uniquness VS performance of a product be it subwoofers, cars or condoms.

Nothing against Paradigm, they know their target audience and what people that purchase their products desire. Instead of getting in a subwoofer "war" where performance is the only thing--they chose (wisely) to offer something different, matches their whatever speaker line and allows all sorts of fun with words from the marketing department. Nothing wrong with that, it keeps the lights on and the profits spend the same no matter if they bought it because they wanted a certain performance level or it matched the curtains better.

The other factor to think about, the DIY crew generally speaking is very performance oriented--BassThatHz has world class performance and yet--his quad amped speakers are raw MDF. Plenty of 10 in subs around, very good ones from the Ultimax 10's to the CSS SDX 10 beasts to play with. The issue is when you want to get high SPLs down low, under 20Hz and for conventional subs (sealed/ported/passive radiator) there is no replacement for displacement. If your goal is performance, you put the budget toward that end. Say I wanted to "equal" a pair of 18's with tens--I'd use eight 10's to do it. Cost would be around $1,100 just for the drivers, much more hassle to cut all those holes, seal all that stuff--more parts, more problems! What is better than a hexagon? An octogon! The CNC milling machine will make easy work of it but the cost is the veneers--more veneer pieces, more chances to screw it up.

In DIY you can do whatever you want---one guy built a massive horn loaded subwoofer and cloned the Tardis from Dr. Who. Looks like a British phone booth....but it is a sub. For this reason, you rarely see "clones" of designs that don't provide performance as the main design principle. Sure, the DIY crew builds really small subwoofers but will make very oddball sizes to better fit their room--custom builds abound for that. My pair of 15" subs in the garage are 6.1 cubic feet tuned to 18 Hz with the port "under" the box so it looks like a "floating end table"--the dreaded WAF they call it. It's not like I can amble down to Fast Eddies Audio Shoppe' and pick up an end table subwoofer of a specific size, specific shape, exact veneers and the exact table top my wife likes. The true design challenge was to stealth the sub at a size that did not throw away performance for looks--I really wanted to use 18's but something that huge would not work. The joy of subwoofers is you can always add more. I'm going for three of them...for now. :D

As far as the PB16 goes--it would be easy to "clone" that one by purchasing that Peerless driver--generally speaking, it does not model well if you can go with a slightly larger box. I did model the driver, looked at the results and the juice was not worth the squeeze. For others, it might be the perfect performance at the perfect size--then go for it! For me, I'd rather go more subwoofers (three) than a pair of crazy subs. Once you learn how to model subwoofers, then you can play around with all sorts of alignments from way too small sealed boxes to massive LLT (Large Low Tuned) boxes or dabble with horn loading. The software will give you a very good idea and you can have multiple proposed builds on the same chart--pick the one that suits you best.

In summation, I'm not saying nobody has ever "cloned" the Paradigm sub--big world out there. However, once you do start building subwoofers, reading/understanding the charts/software, most likely you'll look more towards performance as your guide. This usually eliminates designs that are more a visual thing than a performance thing. All depends on what performance you want, your budget and how much you are willing to part with for finishing.

Hope that clears things up a bit for you--the rabbit hole runs deep here so watch where you step! :)
 

· Registered
Joined
·
8 Posts
Discussion Starter · #16 ·
Really appreciate the feedback, don't think you could have explained it much better,
I'm definitely looking for something on the small side, really not looking past the size of the pb 16, really would love to make a couple of power cubes, as the room certainly isn't gigantic., I guess I'll play around with a few different drivers on winisd and see which models the best for the box size.
 

· Registered
Joined
·
5,338 Posts
I'd also like to know this, an example I can think of is the extremely high end and pricey paradigm sub 2.

Why have they gone with 6 10" drivers? Is there good reasoning behind this vs say 2 18" drivers which would have very similar cone surface area?
They had form factor, size, and shipping weight concerns.
 

· Registered
Joined
·
172 Posts
Really appreciate the feedback, don't think you could have explained it much better,
I'm definitely looking for something on the small side, really not looking past the size of the pb 16, really would love to make a couple of power cubes, as the room certainly isn't gigantic., I guess I'll play around with a few different drivers on winisd and see which models the best for the box size.
Keep in mind... a sealed box for an 18 vs a 15 isn't really too big of a difference in its dimensions. You may find that you end up with an 18 in a sealed box, anyhow, once you start modeling and seeing the performance those few inches get you :)

EDIT: And some food for thought... You can always dial a subwoofer back, if it's too much. Can't really 'over boost' the thing though.
 
1 - 20 of 25 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top