# Seas L18 H1224-08 (7" Midwoofer) Measurements



## Hanatsu (Nov 9, 2010)

*Seas L18 H1224-08 7" Midwoofer*





I'm gonna use this driver for my newest project. It got as good non-linear distortion performance in the midbass as my Scan-Speak 18wu, at least up to 96dB/1m, i.e top class. This is a 7" midwoofer with a light aluminum cone and a phase plug. It got a 12mm p-p Xmax which means it got pretty good output if you use it as a midbass driver. It got an open back design which is good for lowering power compression and improving air flow behind the driver. It does have the downside of being more sensitive to moisture/water since the VC is open to the environment. There's very little motor noise even at full throw. Build quality is good, I had a driver which had the phase plug off center, but SEAS did replace the faulty unit without any questions. 

Here's the measurements;

*Linear Distortion:*



Great linear performance till 4kHz.



Beaming begins around 1,5kHz.



_CSD & Tone Burst Becay_



Nasty breakup due to the aluminum cone at 6kHz.




_*Non-linear Distortion*_

Harmonic Distortion - 90dB/1m equivalent.





Harmonic Distortion - 96dB/1m equivalent.





Intermodulation Distortion - 90dB/1m equivalent











A slight amount of spectrum noise can be seen in the IMD plots where f2 lies in the 1-1,5kHz area. HD5 is higher than HD3 at ~1,3kHz, that's not very good. These distortion peaks are related to the cone breakup. 

The non-linear distortion from 40-800Hz are top class. It doesn't get much better. Even at 96dB/1m it holds up great with a %THD around 0,5 in the lower midbass area.

*Impedance Response & T/S Parameters*



Low Q, low Fs, pretty high VAS.

It fits good for moderately small sealed enclosures and vented alignments. It even does good in "IB" alignments, they yield pretty good output down to 60-70Hz in a typical door.

*Conclusion;*

Great performing driver in the lows and lower midrange, good linear performance up till 4kHz. Full power response up to 1,5kHz, moderately high non-linear distortion above 1,2kHz might "color" the midrange some if you got sensitive ears. I recommend this driver for 3-way front applications, its midbass performance is top notch! If you can live with some distortion, you can basically use the drivers to 3,5kHz with a steep lowpass filter. Considering power response and non-linear performance I'd say the optimal range for these drivers are 40-800Hz. Considering power response only, you can use them to ~1,5kHz. Overall decent price vs performance. For a 3-way front I wouldn't hesitate to use them but for 2-way front applications, there are better drivers out there.


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## kappa546 (Apr 11, 2005)

Fantastic review. Bit of old news as these have been around for like 7 years but good nonetheless. And you're right, these are excellent midbasses in a 3-way.


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## WinWiz (Sep 25, 2013)

Nice review but actually its a 6.5" (16 cm.) and not 7" driver isnt it?


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