A Question on pro audio subwoofers?

[Mark_IDT]

I've noticed most pa speakers have subs with accordian surrounds and minimal excursion. I'm refering to speakers that would have something like 2 15"s 2 mids and a horn. I haven't seen as many decicaded subs boxes like 2 18"s but they seem to use the same types of drivers also. It seems to me that high excursion subs we use in our homes would work better for them but thats why I'm asking.

[This Guy]

The high excursion subs we use in our homes are not nearly as efficient as the pro drivers. For the most part, their application doesn't need super low bass, so around 50 hz is fine with them. 50 hz doesn't require nearly as much excursion as 20 hz. Since they don't need to go that low, they don't need that much excursion and in exchange they can make the drivers more efficient. Although if you want some of both, the Lab horn has two 12" drivers loaded into a folded horn. The two drivers can reach 13mm of xmax, which is much more than the average 12" pro driver. If you stack them, or put it in a corner you can reach 30-25 hz...at ear splitting levels because it's so efficient.

[Mark_IDT]

Are you talking about decibel sensitivity when you say efficient or in by the way it produces sound? Shouldn't a high excursion woofer be able to produce a louder 50hz note sence it can move more. I mean say if sub A has 30mm xmax and sub B has 60mm xmax and both are playing a 40-50hz note sub A is moving say 10mm and B is moving 20mm wouldn't sub B be louder? I understand that it takes a long stroke to move enough air for you to be able to hear a 20 hz note but can't that same sub make use of all that excursion to produce a very loud 40-50hz note. I know both subs A and B wouldn't be only moving the same 10mm to produce a 40-50hz note. It's the amount of cycles per second not amount of excursion that produces the frequency. The physics just don't make sence to me. Also I see ratings on them covering 30-150 hz like this 2-18"s cabinet from carvin www.carvin.com/products/single.php?ItemNumber=TRX218&CID=TRX

If all you were going to use a sub for was music and covering below 35hz wasn't needed then from what your saying it would seem better to get one of these.

I always thought high excursion subs were for making high spl especially for applications like in a car where there is limited room for a box with alot of volume. Now I've really got myself confused.

[This Guy]

I was talking about how sensitive they were. Yes a sub moving 60 mm would be louder than a sub moving at 30 mm at 50 hz. But most of the time the 60 mm sub is not nearly as sensitive. Pro drivers make more sound per watt then home subs at the expense of low end extension and possibly sound quality on the lower end ones. You CAN make a high excursion home sub(s) go as loud as a pro application, but you could possibly need 10,000 watts where with the right pro drivers you would only need 1,000 watts. You just get more sound for your money with the pro drivers. And you're right about the music only playing where you don't need much below 35 hz, which is why I have a pro horn subwoofer. It's a 12" driver going through a 6 ft. pathway, around 104 db sensitivity. It shakes the entire house, and it feels like it's punching you in the chest with just 60 watts going to it. I can give it 400 watts, but the driver can't handle it.

[N. Abstentia]

Are you talking about decibel sensitivity when you say efficient or in by the way it produces sound? Shouldn't a high excursion woofer be able to produce a louder 50hz note sence it can move more. .

Nope, 50hz is 50hz no matter how you slice it. The driver still moves at 50 cycles per second no matter what the xmax. In fact I'd rather have a low xmax sub since it's easier to control and therefore should sound cleaner. Of course having lots of air being moved by a high xmax sub is nice but it's a tradeoff. That's why I have Paradigm Servo subs..the best of both worlds :)

[kexodusc]

Nope, 50hz is 50hz no matter how you slice it. The driver still moves at 50 cycles per second no matter what the xmax. In fact I'd rather have a low xmax sub since it's easier to control and therefore should sound cleaner. Of course having lots of air being moved by a high xmax sub is nice but it's a tradeoff. That's why I have Paradigm Servo subs..the best of both worlds :)

N. Abstentia buddy, higher xmax and a fixed surface area will sweep more air and should create more SPL than a lower xmax sub. Oh, and xmax isn't the only thing that affects efficiency.
You're right though, I prefer low xmax woofers to high xmax woofers and even some servo tech subs.
There's a point where a woofer quits acting like a speaker and acts more like a power tool. I always advise to go with the lowest xmax sub that meets your criteria.
I'd like to see more servo subs hit the market.

[Mark_IDT]

Well like most home stereos I plan to watch movies on my sub as well so that lab 12 horn probably isn't what I would want. Though I would still like see a picture of it or anything about it. This does bring new thought to the idea of using my home sub for large parties though. If these are so much better for music why don't we see them being sold for homes as strictly music subs? My thinking before was that most of the dj speakers I've heard sounded horrible compared to my studio 100's. Though the idiot playing the cds behind them isn't usually in the know about anything audio. I thought I could use home speakers instead and have a much better sound. I'm only thinking for use in rooms like the size of a small bar like 25x35 max. But If I can't use a pair of home subs for that I'll forget the whole idea of getting a sub for a dual purpose.

[kexodusc]

You have to keep in mind most "pro-audio" gear isn't actually the best acoustically (as in sound quality)...the goal is usually biggest bang for the buck...as in loud and cheap, and sometimes duarable.
Sonic refinement is often an afterthought. And rightfully so. Consider where most pro-audio is used...night clubs, out doors, bars, etc...not exactly the most acoustic-frienly venues. The room acoustics (or lack of) will kill a good chunk of the sound quality anyway, so it's much harder to acheive great accuracy at affordable levels.
The only pro-audio gear I see as being really useful for home listening is some amplifiers...especially for subwoofer powering.
There's great sounding pro-audio gear, but it's usually not economically worth it for in-home applications.

For good sound quality, in a 25 X 35 room, two 15" sealed or even ported (home) subs will be more than enough. Just be sure to have decent amps powering them. How loud are we talking here?

[jocko_nc]

Pro Sound equipment is great for playing at ridiculous levels for extended periods of time. For big parties I have a 2 x 10 w/ horn 2-way cabinet that hits obscene levels and is absolutely bullet-proof. Otherwise, I use it with my guitars. Sound quality is not a concern.

jocko

[pelly3s]

the Lab 12 would be killer for watching movies, the problem is is building the boxes and finding the room to put it all. JBL made a box with two 18" 2245's which have a foam edge and it played almost flat to 22hz, but noone really wants that cabinet in their house (unless you are sick in the head like me) it was a theater box and is still used in a lot of theaters

[Mark_IDT]

For good sound quality, in a 25 X 35 room, two 15" sealed or even ported (home) subs will be more than enough. Just be sure to have decent amps powering them. How loud are we talking here?


Well considering I measured my bass at 100db with my 100's I would say at least 110db if not 115db with peaks above that is a good goal. I was also considering using these subs to help my friends band get more bass from his SWR cabinet he's got 4 10"s and 2 15"s and you still can't hear him at times. That dosen't seem fesable now though considering I got him hitting 110db easily with just the 4 10"s playing. I would still like to have a home stereo that can play loud enough to double as an audiophile dj setup though.