4 mobile subwoofers in my HT

[Chongdigga]

Hmm. Not bad. In a 5ft³ box, same as you're buiding now but tuned to 17.5Hz, it'll handle about 150W before reaching Xmax. At that power, it'll play down to 15Hz @ 99dB, 20Hz @ 104dB, have an F3 of 24Hz, and average ~110dB from 34Hz+. It'll be a couple dB shy of your Cerwin Vega at higher frequencies, but it will more authoritatively pressurize the room into subsonics I think. A single flared 4" dia x 19" vent ought to be fine, although there could be some chuffing below 16Hz. Since the sub will be Xmax limited below 14.2Hz anyway, I doubt it'll matter.

If you could budget an extra $25 per driver, this Dayton 12" DVC in a net 3.7 cubic foot box tuned to 19.5Hz would outperform the 15" Classic from 16 - 33Hz (4dB louder at 20Hz at 300W). It'd need two 3" by 24 3/4" flared vents.

Those are some pretty good numbers for $100-$125 subwoofers eh? I like the DVC Dayton's with 300w in a not so huge enclosure idea. Budget is negative at the moment but for sure a future project.

I read somewhere that when using multiple subs they should be the same wattage, diameter, etc..??
Would it be a bad idea to have the two 12"s in the front (where the 12 is now in the pic and the other on the opposite side) and the 15s against the walls to each side of the couch?

Thanks a million for all the work that you are putting into my projects rojo. You are a rare breed.

Edit just noticed that Dayton u recommend is a 12"....so if I went that route I won't have the mismatched sub size problem. Sounds like a plan.

 

[rojo]

Multiple subs don't necessarily need to be the same wattage, diameter, etc. I see people say you can't run a sealed sub and a ported sub in the same system, but I do and it sounds lovely. If what your system is trying to play is a 30Hz tone at 105dB, it doesn't matter much whether that tone is being produced by a sealed 12" at 500W or a vented 18" at 50W. It is still at 30Hz tone at 105dB.

But if you're running a well-tuned sub alongside a poorly designed sub with a ringing impulse response, your system will only sound as good as the ringing sub, which is to say, not very. That's probably the reason behind what you've read. Either that, or it might've been a warning against using a single amp to drive two subs with different power requirements.

In any case, I see no problem with your having the two 12's in front and the 15's against the side walls.

You know, if you're supplying the MDF for the cabinets, then the added cost of the 12" drivers might be at least partially offset by the use of less wood in building a smaller enclosure. Also, the sub still models reasonably well in a net 3ft³ box (tuned to 19.5Hz with a single 4" dia x 26 7/8" long vent flared at one end), only with about 1.5dB less output at 20Hz than the more optimal 3.7ft³. The 1.5dB difference would barely be audible, and probably only if you were doing an A-B comparison.

 

[Chongdigga]

1 of 2 ready for some sanding and paint #2 isn't far behind. The back panel isn't on in this pic but my final pic was all fuzzy. Better pics soon.

 

[Chongdigga]

Here are the specs of the amp I'm getting to power the two CV dual 4 ohm 12s in there new boxes. Any recommendations on wiring.
Power Specifications
Number of Channels2 Channels
Continuous Power @ 8 ohm215 watts x 2 channels
Continuous Power @ 4 ohm350 watts x 2 channels
Continuous Power @ 2 ohm550 watts x 2 channels
Continuous Power @ 8 ohm (Bridged)700 watts x 1 channels
Continuous Power @ 4 ohm (Bridged)1100 watts x 1 channels
Total Continuous Power1100 watts

And rojo I'm definitely going to do the two Dayton 12s with another one of these Crown xls1000s to power them. Gotta save a little cash first.

 

[Chongdigga]

Rojo if I still lived in North Carolina I would drive to Tennessee and give you a hug.
I put the 12 in the new box and WOW! 8db gain is an understatement. Its sounds soooo much better. I played a song that it struggled to pick up the low lows b4 and hit every frequency with athourity and thats still running off the mobile amp. I can't wait to get the xls amp and the other 12. Gonna play a movie thru it later 2night

 

[rojo]

I appreciate the sentiment, but I'm kinda glad you don't live in North Carolina if it meant I'd have to explain to my wife why strange men are driving to my house to hug me. I'd definitely share a couple of beers with you though.

That's great that you achieved such an improvement with a proper box! Congratulations! Wish I could hear it, man. Keep me updated on your builds, definitely.

Sent from my LG-VS980 using Forum Fiend v1.3.1.

 

[Chongdigga]

Getting there

And yes this is happening in my kitchen

 

[rojo]

LOL ooh sharp! I like the red ports to match the red surrounds of your drivers. That's commitment to a project, there. I bet when you get done, Cerwin Vega would appreciate your homage to their stuff.

 

[Chongdigga]

Hey rojo I'm trying to find out the best way to wire the two 12s to the crown amp. Pretty much 550w each at 2ohm or 215 each at 8ohm? Or bridged at 4 ohm getting 550w each? They rms at 250 and max at 1200. Is it true a sub in a big box (like the ones I built) need less power?

 

[rojo]

If I recall correctly they're xmax limited around 300 watts. It probably won't matter much what you choose. If you do 8 ohms per channel your amp will probably run cooler and have less distortion, although I doubt the distortion would be audible in the 2 ohm or bridged configs.

Sent from my LG-VS980 using Forum Fiend OSP v1.3.3.

 

[fuzz092888]

Multiple subs don't necessarily need to be the same wattage, diameter, etc. I see people say you can't run a sealed sub and a ported sub in the same system, but I do and it sounds lovely.

The issue AFAIK, isn't that you can't play them in the same system, it's that because of their inherent properties there's a greater chance of unevenness over the full bandwidth if you don't know what you're doing.

It has to do with what types of tones you are calibrating the subs with, along with some other factors. There's much greater room for error, especially if each sub isn't individually calibrated with either full rang pink noise or a specific sub cal tone.

How noticeable the unevenness is also dependent on a bunch of factors, but if you don't notice anything than why worry

 

[Chongdigga]

The new amp and the other 12 will be here tomorrow

Prob gonna stick a CV decal somewhere on the boxes but other than that they are done.

 

[rojo]

What'd you think of movie night the other night, by the way? Still impressed with your new build?

 

[Chongdigga]

What'd you think of movie night the other night, by the way? Still impressed with your new build?

I decided to skip the movie and finish the boxes. Tomorrow night is movie night for sure tho. I will let you know how it sounds

 

[Chongdigga]

I'm still smiling from movie night
The Dark Knight Rises was the movie of choice and I'm very impressed. The subs where picking up Bane's voice when they were in the hole prison and The Bat scenes....WOW! It sounded like the damn thing was flying thru my living room. I think I ducked once and its not in 3D LOL.
I will post some pics later and thinking about shooting some video. I know playback of it will probably sound like crap but we will see.

Definitely a noticeable change in movies but music really came to life. I listen to literally every kind of music. I like bass obviously. Recent find.. Lindsey Stirling. Techno violinist. Her song "Crystallize" thru my stereo is really amazing IMO.

 

[rojo]

Here's another tasty something for your new subs: High Contrast Summer 2015 mix