Need new sub, thought i would build one!

[Eric Mathews]

where am i supposed to measure it from? it has the port on the top, but the driver down firing? i was just assuming that the 15" in a 320 L box with 800 rms to it would be louder then 2 small 125 W. i mean its even quieter then just one of them plugged in... and that does not make sense.

http://velodyne.com/products/specs/vrp.html
thats the link to my 2 subs, the 1200.

to get a RAW FS i need a mic and software right? my sound card sucks so i hope that doesnt make a difference. where do i get this soft ware?

is it also possible that the box is just SO big that the sound wave is not staying in the room? could a sealed box change this? or a smaller driver?? also my room is kinda werid shape. i kinda drew a picture of the room. the red is the subs, black couches and speakers. i drew a side view as well and you can see i have a big rectangle brace in my roof. so there are a lot of weird corners in there. where the 2 subs are, the most out put is archived.

[Mike P.]

I mean its even quieter then just one of them plugged in... and that does not make sense.

Agreed. Some trouble shooting is needed. What SPL meter did you use for your test? Are you using the Yorkville AP3400 amplifier you mentioned earlier?

[Eric Mathews]

no im not im using a carvin amplifier its 800 watts RMS bridged at 4 ohms. im using a radio shack digital meter

[Mike P.]

What's the model number of the Carvin? I suggest you run some test tones down to 20hz and below and use the correction file for your SPL meter. Hopefully we can track down what the problem may be.

[Eric Mathews]

ok i will run them down to 12 hz then post the output

[Eric Mathews]

ok i finally was able to put some more numbers up, but im still not sure which weight i should use. the SPL meter did not come with any instructions sssoo i just measured it with both. i first measured it at 0 db on my receiver, then i measured it just under clipping and then ran them again. here are the numbers, (no i cannot write this clean it was my girl friend lol). i think i just might need a bigger amp because it moves air... a lot. it shook a big glass dish off the fridge up stairs and it exploded on the floor. the thing is, i can go pretty loud with it with test tones, but as soon as i try to tun the amp up on say, War of the worlds, then the amp clips . im not sure if putting the sub in a sealed box would make any difference or not, maybe a smalled driver.... i dont know help! thanks

Eric

[Blaser]

This sub is VERY deep (pretty flat down to 12 Hz) and that's why it is not very loud. You need more of this sub. Adding a second colocated fed with another identical amp will add 6 db to these readings.

[Mike P.]

Did you use the correction file for the SPL meter?

[Blaser]

From the readings I think he didn't

[Eric Mathews]

Mike P. wrote:

Did you use the correction file for the SPL meter?

no those are the exact mesurements from the RS spl meter. Does it matter that this is the digital one and not analog? do i just add whatever db it has on the chart for that given hz?

http://forum.audiogon.com/cgi-bin/fr...6&openflup&1&4

is this the chart you are talking about?
thanks

Eric

[Mike P.]

The file for your digital SPL meter is on the downloads page.

http://www.hometheatershack.com/foru...oads-page.html

[Owen Bartley]

The numbers look pretty good, and very flat. Maybe the 12s were a little "boomier" with more power in the upper range, which is more noticable to our ears? If this thing is shaking dishes off shelves, it has to be producing some good low bass. Can you feel the floor/furniture vibrate when watching movies? Is there more of a tactile sensation than with the 12s?

[Eric Mathews]

ok so i picked up a new ep2500. this made a big difference i bridged it for 2400 RMS. i cant really feel anything shake, but i think that is because it is a basement and the floor and walls are cement, sssooo ya. my old amp would clip if i turned it up too much but this amp i have it as just past 1/4 and it wont clip at all!. oohh MR Mike P. how do i use this calibration file? i downloaded it but i suck with computers and i dont know what the file extention is. thanks for all the help!

[brucek]

how do i use this calibration file? i downloaded it but i suck with computers and i dont know what the file extention is.

The calibration file is in text format and can be opened with notepad or similar text editor, or you can append a .txt extension to the filename (using rename) and then simply double click the file and it will open.

The format is frequency versus dB level (showing the level that the meter reads low or high from zero dB). For example an entry of ( 20 -5.0) would mean at 20Hz, the meter reads 5dB low, so you need to add 5dB to any reading at 20Hz.

But, it would be far better to download the excel file that matches your meter from the download page instead of having your GF write down stuff on a piece of paper.

This is the excel file for the digital meter. Simply put your raw meter readings into the cells provided and the results are compensated with the calibration automatically. It also draws a swell graph. You can download the sinewave tones from here and burn them to a CD and use them to create the cell entries, or use the sinewave tones you already have.

brucek

[Eric Mathews]

thank you SO much for explaining that it all makes sence now!!! ssoooo i guess the mesurments arnt that bad then, hm. i still think my room accoustics are horrable, but at least now i know there is nothing wrong with the sub.

[Owen Bartley]

Eric, have you walked around the rest of the room, or even the house while playing some bass heavy content to see how it sounds? It's very possible that you just have some room problems, and maybe relocating the sub will help that. I know I have a few areas in my living room where the bass sounds better, and a few where it sounds a lot thinner and worse.

[Eric Mathews]

ya i have moved the sub all around the room, and where it is now, it sounds the best... but with the new amp it sounds better so i think im just gonna have to be happy the way it is lol, untill i get a new house. thanks