# Review: Hertz HKS 165 vs Focal 165K



## chuyler1 (Apr 10, 2006)

This is part 3 of my search for midbass drivers. If you missed part 2, please read Review: Focal 165K vs Adire SF7. If you missed part 1, please read Still can't dial in the CA18RNX!

I have been listening to and tweeking the Focals for the past 3 weeks and although they have their limitations, I was able to get some pretty convincing sound out of them. Because of their high sensitivity above 1KHz I ended up with the following settings:

Highs: LPG 26NFA, 40w RMS, 3.7KHz-20KHz (24db/octave)
Mids: Focal 165K, 85w RMS, 55Hz-3.7KHz (24db/octave)
Cut 250Hz -3db, Cut 2KHz-up -6db
Lows: DLS OA12, 300w RMS, 20Hz-55Hz (24db/octave)

Cutting the upper range with a shelf filter definitely tamed the beast while still providing plenty of detail. I still prefer the midrange of these over the seemingly dull Adire midranges from my last review.

For starters we swapped in one Hertz mid and left everything the same. Immediately we noticed a lack of upper midrange so the EQ settings were turned off to be fair to both candidates. Switching between left and right revealed that the Focals have more deep bass below 100Hz while the Hertz have more punch (possibly because their suspension isn't fully broken in yet). The Focal midrange is harsh above 1-2KHz while the Hertz stays pretty neutral in comparison but will breakup if pushed further. Rock guitar work on the Hertz isn't as detailed but doesn't fatigue your ear at loud listening levels. Although not perfect on the Hertz, some snair drum cracks were absolutely unbearable on the Focals without my eq settings. Female vocals like Dido had a hint of nasel sound to them on the Focals with more emphasis on breath while the Hertz were more laid back, less in your face, but lacking the presence. Again increasing the volume on the Focals introduced fatigue while the Hertz just got louder.

Next we put the other Hertz mid in and did some more listening. We found without the detail of the Focals the tweeter gain had to be turned up. The additional bass that the Focals appeared to have was not missed but the hertz didn't seem to keep bass lines and bass drum hits as transparent. In other words, at loud volumes the bass seemed to get a little muddy. Again, this could be because the suspension isn't fully broken in or perhaps the lower XMAX has something to do with it. Aside from the bass, the midrange was very smooth and blended pretty good with the LPG tweeters.

Next we decided to install 1 Hertz tweeter. Right away, we noticed the hertz tweeter filled in the missing upper range detail that the Focal mids had been providing to us. Cymbols were clear and you could distinguish high-hat, vs large, vs small cymbol crashes. Vocals had more bite as did guitar licks. At full volume they introduced a little ear fatigue but they weren't as bad as metal domes I have listened to. The Hertz tweeter is much more efficient than the LPG so we'd probably have to turn the gain back down.

We concluded that the Hertz set was well matched and installed the 2nd Hertz tweeter. With the full set installed, the dynamics of the system was very good. My previous tuning had left the system with Focals/LPGs somewhat dull at full volume. The Hertz just come alive with brightness and detail.

Next we pulled out the RTA and did some measurements. I'll post the graphs soon but unfortunately I don't have any graphs from the Focal/LPG setup. We found two issues that were easy to fix. First, the tweeter level was noticiablly higher than the mid so we lowered that by about 2db (and I lowered it another 1db on my ride home). Also we found out that I accidentally had the subwoofer amp crossover turned on in addition to the DCX-730 crossover. Actually, it can't be turned off, but I raised the amp to 90Hz(max) so it wouldn't have any affect. After some listening, we switched the crossover to 18db/octave @ 55Hz. I also decided to try a 12db/octave 3KHz crossover point for the mid/tweet to get a little more detail into the midrange. There are other issues that will need to resolve that are relative to my car but I can dial those in by ear later now that I have a visual reference of the system.

Finally we listened to a little more music to finalize our afternoon. Overall, I feel I am missing the pant-leg shaking kick-bass I got from the focals but other than that I feel this is a successful upgrade. The midrange is smooth without too much bite and the tweeters offer a little more edge (but maybe too much). This morning I switched to a 24db/octave 3KHz crossover for the ride to work and I still feel I can't turn the volume up as much as I would like without getting ear fatigue. I am going to raise it up to 3.7KHz for the ride home to see if that helps.

So the out-of-the box winner definitely goes to Hertz. I didn't try their passive crossovers but not having to cut the majority of the upper midrange is a huge plus in my book, especially when using a compact tweeter. If one were to use a large format tweeter I think my preference might sway toward the Focals though since they have better excursion capabilities and deeper midbass overall.


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## mvw2 (Oct 2, 2005)

One small note. Try dropping down the overall tweeter level .5dB or 1dB instead of raising the x-over point. Since you mention the upper midrange response of the Hertz is laid back and seems to rely on the tweeter, make good use of the tweeter. Generally if the tweeter is harsh, some frequency its playing is overpowering. Dropping the attenuation down should help. You should be at the point where neither the tweeter nor the woofer over drive the other. If it is already at this point, you may just have to sweep through the frequency range with EQing and find the trouble spots. There probably is an obvious one when you hit it. I have a personal preference towards using pink noise for frequency response balancing as its completely unbiased and contains all frequency information all the time, unlike music, but use what you're comfortable with. You do mention using the RTA, but also note that RTA flat isn't ear flat, so you may still have to shape the response to your ear to sound correct.

Also with a change of drivers, you may find yourself having to tweak time alignment a little as well.

I know it's fun to play with all these drivers, but it's also a good bit of work to dial in each one. Thanks for taking the time and effort to write up the review. As you swap in and out new hardware, keep them coming.


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## chuyler1 (Apr 10, 2006)

Thanks for the comments. I have actually dropped the tweet about 2 more dbs over the past few days but currently I'm sticking with the 3.7KHz 24db slope. Now that I have the level closer to what I like I may try dropping it back down to 3KHz. On the RTA there was a noticable peak around 12KHz so I cut that a few dbs and that helped the staging a bit but I don't think its related to any harshness.

I use the RTA results primarily to figure out the capabilities of drivers and verify crossover points and phase/cancelation issues. I also use it to find peaks coming directly from particular drivers. But the drivers themselves are "starting points" and that is what I was trying to review here since not everyone has the equipment to tune every frequency.

For example, I boosted 33Hz/Q3/+3db because the RTA showed a noticible gap in subwoofer output centered at that frequency using both pink noise and sweeps. 25Hz was fine and 40Hz was fine...I'm sure this is due to some cancelation from vibrations or poor sealing of my trunk (the sub is IB) but boosting it sounded fine for most music.

I am now cutting 250Hz/Q4/-6db cleared up the muddiness. Cutting 550Hz/Q5/-4db also cleaned up the response a bit and made vocals more natural sounding. There was also a spike at 1.2KHz that I cut but I haven't determined yet if it makes any difference. Finally I cut 6KHz/Q5/-3db on the mid only since the full range RTA of it showed a peak there which was still identifiable after enabling the crossover.

With all this set things are starting to come together.

As far as time alignment goes, I haven't touched it for any of my speaker setups. That is usually the last thing I worry about and since I often drive with my wife in the car I'm not really interested in optimizing it just for one side of the car. The last time I messed with it I felt it added a hint of reverb/echo to the music. When tuning Oleg's car the other day we noticed the T/A settings he had introduced some pretty bad cancellation in the 3-6KHz region. Not sure why, but things sounded much better without T/A.


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## mvw2 (Oct 2, 2005)

Man, I love the stuff, but I do agree, you are still only setting it up for one location which is kind of a sacrifice. The same goes for if you start playing with the EQ separately left and right. You keep stepping towards the one person experience. You get better results but it's a trade-off either way. Keeping the wife happy is #1.


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## chuyler1 (Apr 10, 2006)

Yep, she already commented about the staging...which is apparently lower and more to the side. I think its caused by clarity and volume of the tweeters and the fact that she's coming from her car that has tweeters mounted in the a-pillars instead of the sail panels.


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