- Written by Chris Heinonen
- Published on 02 May 2012
The Paradigm SUB 1 on the Bench
The single subwoofer measurements were taken from 1 foot away in the center of my listening room. The PBK measurements were taken when the SUB 1s in their installed position, with the microphone at my listening and calibration position around 10 feet away. Taking measurements outside was not possible as the winter in Oregon is rainy and doesn't permit me to put a $5,000 piece of equipment out in the elements.
To see how low a single SUB 1 can play in my theater, I used a 20 Hz tone and tested until I got close to 10% distortion.
You can see I managed to get 9.2% THD+N with 104dB of output. Trying the same test with an 80 Hz tone as opposed to the 20 Hz tone managed to produce almost 123 dB of output.
Listening levels like this are going to be uncommon, at least if you want to keep your hearing, so I went for 100 dB of output at 80 Hz, and had less than 1% THD+N at that level.
Aiming for 100 dB at 60Hz and 50Hz gave me THD+N values of 3.6% and 6.1% respectively. We will see better examples of why in the next set of graphs.
Looking at the Frequency Response, we see that there are definite room issues at around 35Hz and 65Hz, with some extra room gain at 80 Hz. Testing outside would have eliminated the room interaction here, but that wasn't a possibility. You can see that we were able to do 90 dB of output here quite easily, with very low THD+N and good, solid response down to almost 10Hz.
Looking at the THD+N vs Frequency graph, we see large rises at those room nodes, as the subwoofer has to work harder to make up for the issues. I also have a lack of faith in some of the lower measurements; as between 10 and 50 Hz objects in the room would start to rattle violently. From door handles to a sliding door to the walls themselves, there was so much noise being output from items other than the sub that some of it was likely picked up in the measurements.
This was for a single SUB 1 in the middle of the room, but what about if I used Dual SUB 1s in my listening position? How effective would the Perfect Bass Kit be at correcting any issues that arose? The PBK is very easy to use, so I could measure both with and without PBK to see what the changes were.
I kept the output levels the same between tests, so any lower output levels are due to PBK making corrections that affect the output level. With a 20Hz test tone, we see that the output level drops slightly from 109 to 105.5 dB, but the THD+N also falls from 6.8% to 3.9%. That secondary harmonic also drops from around 20 dB below to almost 30 dB below the fundamental.
Looking at the 60Hz test tone, we have virtually identical output levels here but the THD+N falls by 25% and there is a huge reduction at the third harmonic up at 180 Hz here. We also see this with an 80Hz test tone, where the noise floor is much lower in comparison to the unequalized setup.
Looking at the THD+N vs. Frequency graphs, we see that from 20 Hz to 80 Hz, which was my target, the sub is below 2% THD+N almost the whole time. Looking at the same data but without PBK engaged we see that the THD+N rarely even falls below 2% in that same spectrum, and has a spike close to 10% that is completely absent in the PBK version.
Finally to see how much I can push two subwoofers with PBK, I ran that 60 Hz test tone again. As you can see I got to 144 dB with just over 3% THD+N, at which point my ears were making me quit long before the SUB 1s were. Overall the SUB 1s had some really powerful output, and the PBK showed how effective it can be on both the bench and in real life.