- Written by Chris Groppi
- Published on 22 October 2009
- Legend Acoustics Tikandi Speaker System with DEQX HDP-3 Processing
- Page 2: The Design of the Legend Acoustics Tikandi Speaker System with DEQX HDP-3 Processing
- Page 3: Setup of the Legend Acoustics Tikandi Speaker System with DEQX HDP-3 Processing
- Page 4: The Legend Acoustics Tikandi Speaker System with DEQX HDP-3 Processing In Use
- Page 5: The Legend Acoustics Tikandi Speaker System with DEQX HDP-3 Processing On the Bench
- Page 6: Conclusions About the Legend Acoustics Tikandi Speaker System with DEQX HDP-3 Processing
- All Pages
The Tikandi system was delivered from DEQX's US importer, KRC, by Larry Owens. Larry helped me set the system up, a process that took about 6 hours. After that, I was left to myself to play with the system, and also use the HDP-3 processor with my own speakers and amplifiers. The setup process I went through with Larry will help to explain just how the HDP-3 processor works. Several of the steps had already been done in advance. The basic configuration of the system was already in place.
The Tikandi is set up as a 2-way plus stereo subwoofer system, requiring a low pass filter for the woofers, low and high pass filters for the midrange and a high pass filter for the tweeter. The crossover points and slopes were already set to something known to work well, and the loudspeaker measurements of the tweeter and the midrange had already been made. We just used these settings. After positioning the loudspeakers and cabling everything up, we put the microphone at the listening position and hooked the laptop running the HDP-3 software up to the processor with a USB cable. We did a loudspeaker measurement of the woofers with the microphone at the listening position to provide both loudspeaker and room correction from 20-150 Hz. After making the pseudo-anechoic time-gated sweep measurements for both the left and right speakers, we windowed the measurement by looking at the time domain response to exclude as many reflections as possible while still giving us enough data to cover the bandwidth we needed.
We then chose the frequency range and allowed boost and cut amounts for the correction, and allowed the software to compute the correction filters. Making the choices for the time-window settings, frequency range and boost and cut limits is a bit of an art where Larry's experience was essential. The resulting filters were trying for flat response from about 18 Hz to 150 Hz. Verification measurements showed that the result was within a few dB over the full range! We then made room measurements using both the woofers and the pods. These measurements are made separately and then plotted on top of each other. With the woofer room correction already done, we used these measurements to perform EQ on the midrange from 150 Hz to about 5 kHz. While the automated routine tries to correct every bump and wiggle, we applied the EQ manually, just correcting major deviations.
The key here is to have restraint, making subtle, broad-band corrections to get an overall flat response without trying to correct every little bump. Since the HDP-3 can't measure the woofers and the pods simultaneously, we measured the speakers full range using another software tool and a professional Firewire soundcard to be sure the crossover region at 150 Hz was performing as expected. Everything was in order, with pancake flat frequency response from 18 Hz to just above 20 kHz. In addition, all three drivers were perfectly time aligned to 0.1 ms. With linear phase crossover filters used, the entire frequency range, including the crossover regions, is not only flat in frequency response, but flat in phase (i.e. time) response as well. This is quite literally impossible with passive crossovers.
I didn't save screenshots of the setup, so Larry sent me some screenshots of the DEQX software when he was setting up another speaker system (Klipsh Heresys).
The system configuration window is where the basic speaker configuration is set, along with crossover settings, time delays and gain corrections for each channel.
After configuration the first step is loudspeaker measurement. The top figure shows the raw loudspeaker measurement with the chosen crossover settings.
The middle is the resulting correction filter calculated from the measurement. The bottom figure is the measured result after the correction filters are applied plotted over the original measurements (in the near field).
After speaker measurement, the room correction is taken care of. The above figure is the in-room response at the listening position with and without the correction applied.
Finally, while listening the control panel window allows real time control of the volume, saved configuration plus allows tweaking gain and time delay for each channel of output.
All this technology is cool, but how does it sound?
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