I went yesterday afternoon to do some setup and begin experimenting. I simply connected one pair of HC12 speakers and the bass box. I played organ music and begin to experiment with the sound measurement equipment and software I bought. (This runs under Windows. I’m not sure if they have anything for the Mac crowd.) The software and equipment are new to me, so I’m learning. Any measurements don't mean anything if I'm not doing it right, so anything I post must be viewed with that in mind. The software is TrueRTA. It is freeware for versions with fewer features. But I bought the upgraded package to have those features ($99). It comes with a minimalist help system, so I’m feeling my way along with it. Here’s a link for it, if you’re interested.
TrueRTA Audio Spectrum Analyzer Download Page
The calibrated mike is the Dayton EMM-6 (about $45), bought from Parts Express. (I also downloaded the calibration software from the Dayton
site.) It plugs into a box for Phantom Power and into my computer by USB.
I have RCA splitters and patch cables on the outputs of the
CD Player (Tascam). One stereo pair goes to the HC12s with 16 gauge cable. One channel goes to the bass speaker. I didn't get the other channel connected for the initial experimenting.
Remember that the HC12s are facing the congregation. Currently, there are large wooden pipes right in front of them. Imagine speakers pointing to a wall. I pulled them back about 3 inches to create a gap for a bit more sound to come out. But they are restricted by their position. And everything is so tight in there that I can’t turn them. The bass speaker is positioned so the drivers are facing the sharp corner to the right of the door. The bass cabinet is on 3 inch feet which allows unrestricted activity from the port.
I have one of the Crown XLS1000 amps set to bypass the crossover system. It powers the two HC12s. It is running at 8 ohms - that's a capacity of 225 watts per channel RMS.
The Crown XLS1500 amp was set for a lowpass filter using a crossover of 270 Hz. The crossover can be adjusted. I did some experimenting to attempt to find a sweet spot. The lowpass filter takes ONE channel of the input and sends the filtered signal to both output channels. Thus, the 2nd channel input is offline. (FYI: Crown now has a newer models in the XLS series that allows one channel to do lowpass and the other channel to do highpass. It wasn't available when we bought ours.)
That means the bass speaker is getting some of the same signals as at least one of the HC12s. It just filters out those above 270 Hz. But there is some overlap between the crossover point and the lower limit of the HC12 woofers - which appears to be roughly 32 Hz. But there is some volume rolloff below 40 Hz.
We will also have a separate HC12 speaker (if space allows) that will run through another XLS1000 set for highpass filter. It will take the opposite channel of the pedal outputs from the bass speaker. I'll do th
I want to repeat this: the Artisan sound engine has 8 outputs, divided into four stereo pairs. The software allows digital sounds to be routed to any of those 8 channels. That is not the case with what I’m currently doing. The
CD player only has a 2 channel stereo output, as do the CDs. So splitting the signals and sending them to separate amps results in some duplication of signals being sent to the speakers. I anticipate that some sounds will overlap and be duplicated in area of 40 to 270 Hz. A woofer on a HC12 and the bass speaker will be playing the same sounds. So they will probably sound louder in that particular area of the sonic spectrum. That won’t be the case when everything is connected via the sound engine. But I can’t duplicate that now.
Here's a spectrum analysis on the final chord of the Toccata and Fugue in D Minor by Bach.
I also played some sine waves to measure output.
Here - for perspective - is a 85 Hz. sine wave being played.
And here is one at 21 Hz. - all settings the same:
That's my first stab at using the software and equipment for measurement. I'm open to all sage observations.
Bach On