JL Audio ZR800-CW 8″ Midbass

Up for test is JL Audio’s ZR800-CW 8″ Midbass.  Specs can be found here.

IMG_2243 IMG_2245 IMG_2250 IMG_2248 IMG_2247


Small Signal Parameters

Results as measured via Dayton’s DATs measurement tool.  Which is a very little handy tool to have.  😉

  • f(s)= 56.52 Hz
  • R(e)= 5.35 Ohms
  • Z(max)= 54.75 Ohms
  • Q(ms)= 11.113
  • Q(es)= 1.205
  • Q(ts)= 1.087
  • V(as)= 14.310 liters (0.505 cubic feet)
  • L(e)= 0.90 mH
  • n(0)= 0.20 %
  • SPL= 85.21 1W/1m
  • M(ms)= 31.46 grams
  • C(ms)= 0.25 mm/N
  • BL= 7.05

zr800 impedance


Frequency Response

Frequency Response and the following Harmonic Distortion measurements were taken using Dayton’s OmniMic measurement system.

The frequency response measurements below are on-axis (0 degrees) and off-axis (15, 30, 60 degrees), measured at 2.83v/1m.

zr800 fr 0 15 30 60


Harmonic Distortion

The following HD graphs are done in the nearfield, emulating the following SPL levels at 1 meter: 90dB, 96dB, and 102dB in order.

zr800 hd 90 zr800 hd 96 zr800 hd 102




Frequency Response:  Average sensitivity in it’s primary range is approximately 86dB @ 2.83v/1m.  On the low end, the Qts indicates a high value of 1.087 and a Vas of approximately 0.50 cubic feet, which means this driver is likely built for an infinite baffle type install.  According to JL’s literature, that’s indeed the case: “The ZR800-CW is a supremely powerful, dedicated mid-bass driver designed for infinite-baffle or door-mounted custom installations.”  This driver exhibits fairly linear response up until about 500hz where some issues occur.  Looking at the impedance graph you can see a resonance show up in the 600-700hz region.  This shows up in the FR with the strong dip just around 700hz.  From 700-1200hz there’s odd behavior, and above 1200hz the response gets better.

Harmonic Distortion:  I’ve provided HD measurements at (3) different SPL levels: 90, 96, and 102dB.  The reason I do this is to see the general trend of how distortion increases with output.  But since this is a midbass and likely will be pushed hard, I’ll evaluate the 102dB level distortion.  The 3% THD mark is hit at just under 40hz.  From 60-300hz, where these are most likely to be used, the distortion level is approximately 0.60%.  At 500hz the THD reaches 1% and rides that range until it begins to fall at ~1200hz.

Bottom line: As a dedicated midbass in a 3-way type system (or a 2-way using a ‘wideband’ driver) this is an excellent choice.  From the data, it is seen you can reach pretty hefty levels with very little distortion (less than 1% THD) crossing this driver between 50/60hz to about 300/400hz.  This coincides with the FR data as well.  I wouldn’t recommend crossing this higher than 500hz, though because the response gets pretty rough above this point and it would be hard to implement a crossover here.  Regarding the low end output, keep in mind cabin gain comes in to play in most cars at about the 60-70hz region and increases the SPL below this point by ~12dB/octave.  Which means some people may be able to run these without a dedicated subwoofer and be plenty happy … obviously this is very much user dependent, but I will say I’ve done it a few times myself and have had good success using a 50hz/LR2 crossover but I miss my subs too much to not use them.  😉

PS:  If you would like to help me keep up funds for testing, there’s a little ‘contribute’ button that goes through Paypal all the way at the bottom of every page.  Any little bit helps.

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