Miscellaneous Measurements ***NEW INFORMATION***

[Ilkka]

This is the place to show some measurements which won’t quite fit into the group with other ’formal’ measurements, but are still interesting to show and investigate. This means in-room measurements, comparisons, different EQ settings, different enclosure orientations etc. I’ll be adding some interesting info from time to time, so remember to check this thread periodically.

[Ilkka]

As said in the methodology post, enclosure orientation can be a bit tricky with certain subwoofers, Proson Stratego Sub 12+ is one of them. It is a front-firing subwoofer, but has a port in the back. Of course the most reliable and convenient way to find out the best possible orientation is to measure all of them and choose the best one – and that’s exactly how I did it. Graph below shows the measured frequency response with woofer facing the mic (2 m distance measured from the front baffle) and another one with the subwoofer turned sideways (2 m distance measured from the center of the driver/enclosure mid-line). Naturally the input level was kept identical. As you can see, the sideways option gives a slightly better extension, although the response is rolled-off quicker above 100 Hz due directionality of higher frequencies. Sideways option was used with this subwoofer.

[Ilkka]

Dr. Hsu recommends that HSU subwoofers should be measured laid on their sides, with the woofer and vent(s) equdistant from the mic. Naturally I wanted to measure if this position was any better from the normal down-firing position. Graph below shows the measured frequency response using these two positions. 2 m distance was measured from the center of the driver (directional line from the mic). As you can see, the recommended position gives more output above ~50 Hz, being around 2 dB at 100 Hz. Naturally this is again due directional nature of higher frequencies. I was having a bit hard time deciding which position I should use, but eventually I choosed the normal down-firing position. This was because I wanted to test all subwoofers in their normal operating positions (IMO fair to all subs) and HSU VTF-3 MK2 is a down-firing sub. No other down-firing sub was laid on its side (and possible base plate removed) either. Although also other down-firing subs can be expected having same kind of boost at higher frequencies like VTF-3 MK2 when positioned alike.

[Ilkka]

I haven't updated this thread in a while so it's about time to add some miscellaneous measurements.

There was some controversy about whether the Axiom EP600 should be measured with its enclosure lying on the ground (horizontal) on standing up (vertical). Some people claimed that the vertical position would give it a flatter frequency response. Well since I am more of facts than fiction type of a guy, I measured it and here's the result. The horizontal position gives it a flatter frequency response, so that's why I used that orientation in the first place. Case closed.

[Ilkka]

SVS SB12-Plus was the first SVS to contain a so-called room compensation control. It helps to make the subwoofer sound better in different sized rooms by cutting down the lowest frequencies. The range of the control could be a little bit larger though, and also the corner frequency could be a little bit higher. Now the control doesn't have much impact until at 20 Hz and below, and usually those frequencies are not the ones causing the problems.

[Ilkka]

The Rythmik Audio DS 12" offers total of 9 frequency response shaping settings. User can select the amount of damping (Q) and the extension from three settings each. Damping can be HI, MID or LOW. Extension can be 14 Hz, 20 Hz or 28 Hz. Here are all 9 different settings. The range of settings is really wide so user can tailor the frequency response quite easily for different kind of rooms. I wish we would see more of this kind of controls.

[Ilkka]

The JL Audio Fathom f113 has a setting called the E.L.F trim (Extreme Low Frequency). It can either boost the low end by 3 dB or cut it down by 12 dB (or anything in-between). The range of the setting is wide and also the corner frequency is high enough so that the subwoofer can be also set up in the very smallest rooms without excessive low end output. The JL Audio has executed this control very well.

The measurement below is showing the extreme ends of the setting (fully variable control).

[Ilkka]

The SVS PB13-Ultra has the same room compensation control introduced in the SB12-Plus. User can select bypass, large, medium or small according to his room size. The range of the control could be a little bit wider. Now there is only around 4-5 dB of difference at 20 Hz at the most, which isn't very much. Also the corner frequency is quite low which makes it a bit less versatile and useful.