BillFitzmaurice.info

I already have that, I have a Dayton measurement mic and icicle usb interface for phantom power...

http://www.parts-express.com/pe/showdet ... er=390-801
http://www.amazon.com/Blue-Microphones- ... le+usb+xlr

I don't have to go back 10 meters to listen to 28.3 volts, thats the problem, it just isn't loud... unless I take it inside which I just did. Stuck in a corner it puts out... just wish for my money it did that outside. Haven't SPLed it inside because my parents are going to sleep and I should too.

Plus, make sure that the mic is calibrated for the software against a known good one that is accurate.

Tom Smit wrote:Plus, make sure that the mic is calibrated for the software against a known good one that is accurate.

Tom you're referring to SPL matching right? Because the Dayton comes with an equalization file the only thing it needs to be accurate is setting the gain level versus an accurate SPL meter. I'm assuming that's what you meant... I agree. If it was a matter of +-5 dB I'd agree with you, but 13 db... when I just verified that it isn't leaking, has me baffled for the time being.

fyi, I measured 99 dbs outside at 50hz with a single t48 outside a month or so back, (about 30 volts, 10 meters) smaart v7 apex 220.

next time I get the chance I'm gonna screen cap some charts and show em.

I believe you I just don't understand why mine is so far off... I will be contacting an authorized builder (and paying him/her) to take a look at it some day. Building speakers is a lifelong passion for me, but at this rate I'd be better off sticking to tops and letting pro's build the subs. I appreciate all the comments guys, I really do, it makes my day reading this thread and I do my best to keep a positive attitude even things turn a bit south.

Here's a picture of the sub in my room. For those who don't know the speakers are TLAHs at 40 inches (standard) and that's a 46 inch diagonal tv...

In other words, if you're planning on building one of them, know what you're getting into . It just barely navigated the corners getting into my room.

MissileCrisis wrote:

Tom Smit wrote:Plus, make sure that the mic is calibrated for the software against a known good one that is accurate.

Tom you're referring to SPL matching right?

Yes, that's what I meant.

Hey MC, after all the questions you got on mic, meter, A,C weight, Ifigured id get the same with my dbx mic, phantom power and RTA software I went ahead and secured this!
http://www.ebay.com/itm/AudioControl-SA ... OC:US:1120

There will be no questioning here.

PS, hope you find a solution

MOTHER OF GOD, nice toy.

I hope I find the solution as well. And trust me, I won't stop trying until I do.

MC, I figured if im gonna be building I should also be able to test accurately. The owners manual also has good info in it, ah and yes another toy

pumpsfast wrote:MC, I figured if im gonna be building I should also be able to test accurately. The owners manual also has good info in it, ah and yes another toy

Does it come with a free sky hook? Perhaps measuring in outer space is easier than solidfying the process of how measurement should be done in the mind of a noob (and I mean me here). See --->

I was checkin these out this morning - very nice:

http://www.prosoundnetwork.com/article/ ... sp495/8899

CJ, nice unit. Ahh a sky hook, would come in handy when I have to work on this
https://www.dropbox.com/s/7yq1rhuw51bom ... .58.38.jpg

And as a nube myself, Ive been doing alot of reading about measuring, finally wrapped by head around the harmonics thing and the difference between direct radiators and folded horns.

http://start.mobilebeat.com/showthread. ... olded-Horn

Now I can explain the difference between the too!

I feel like my TUBA60's might not be thumping as hard as i'd like them to be also. Maybe I should do an SPL check? Is it necessary to EQ the subs? I think the low freq EQ bars are all the way down on my eq graph on my dbxpa+. This is after RTA with a side wall obstruction atleast 15 ft away outdoors. Is this normal?

You should manually set the 25 Hz band to ~+3->5 if you want the subs to play flat (that's all the EQ I needed not accounting for room modes). EQing all pro audio gear is a requirement (Bill says this a lot ), and I agree with that. So yes eq your subs. A side wall shouldn't make a big difference outdoors but just to be safe move it out another 10 feet from that wall (if possible). Take an SPL measurement if you can (people recommend 28.3 V 10 m as a 2w/1m reference for the dual loaded's like you have) with a well calibrated mic/spl meter and let me know what you get. Forgot to mention, make the measurement at about 50 Hz such that it is easy for your voltmeter to read the sine wave. One of the sensations you are missing with the Tubas is the fact that they don't have any harmonic distortion so they sound less loud even if the spl meter disagrees . That's why I said measure.

O1S, The RTA feature on the PA+ is a tool to help you when setting up, just a tool. Eq'ing is entirely up to you.
Music is supposed to be clean and balanced, the purpose of an eq is to adjust down some thing that is to high or boost some thing that is too low, similarly if you tops are over coming you subs, turn down your tops and the bass will sound louder. There is a lot of fiddling around to get you system dialed in to a good balance. The venue has a lot to do with it also, obviously outdoors is a whole different ball game to indoors, thats where the PA+ wizard RTA comes in, to quickly measure the indoor room nodes and compensate for them with a relatively flat response, it is not the end all there, it will sound good but not great, that's where your ear and fine tuning comes in. There is so much to say about eq'ing, Id suggest some reading if your not sure.

Those Tubas are supposed to be really thumping, the build was great and you have the power. Before doing anything double check the voltage going to them at the rear of the amps and also at the end of the speaker cable run, it should be the same or very close.

One thing to mention is that our ears compensate overtime for sound levels, i.e if listening to loud music over time it will seem to get lower, its our body adapting. When tuning its good to take breaks and let the ears return to normal and then go again.

To measure the cabs response you will need a SPL meter which has c weighting and a tone sweep, or you could do it manually, with individual tones, 20hz, 30hz, 40hz up to your LP setting or say 100hz.
All enhancements on the PA+ should be off and eq set at zero across the sub freqs. Better yet google test tones and use your laptop to generate the tone, send it to the amp, adjust voltage at the amp output to 2.83v, move sub into a free space with at least 50ft of nothing around it, plat test tone and put spl meter 1 meter on a towel in front of the cabs mouth. This way you will be measuring only the cab and nothing else. For every tone you play measure the spl and right it down next to the freq played. After compare to SPL chart of cab posted here

http://billfitzmaurice.info/forum/viewforum.php?f=12

you can repeat test at 10m distance and 28.3v

Even this simple test is not the end all of test, its merely a reference. If the figures are close to the cabs spl chart all is well, if way off something might be amiss with the cab or driver and that where the fun starts, ask missile crisis .....