Question about speaker frequency response specs

[jtrosky]

So I posted this over on DIYMA, but never got a response, so I figured I'd give it a shot here... :-)

I have a stupid question for you guys... My Kenwood Excelon dash speakers (3.5" mid/high coaxial) list their frequency response as 800hz-23khz. I have never seen a 3.5" speaker with such a frequency response spec (the 800hz part). Most 3.5" coaxial speakers like this list the lower frequency as 80hz, 85hz, etc... Could there really be a valid reason why they list the lower frequency as 800hz?? I'm currently running them with an active 500hz 24dB LR high-pass crossover and the response is fine. If I didn't know better, I'd swear that the spec was a mistake and that it's really supposed to be 80hz, like most of the other mass-produced, inexpensive 3.5" coaxial speakers. :-) But surely, Kenwood couldn't make such a silly mistake, could they (it's listed that way everywhere, including Kenwoods site).

I actually have the 6x9/3.5" component set they sell (but they sell the same 3.5" speaker separately) - and they do say that the included passive crossover for that set is a 850hz crossover - I'm assuming this is a 6dB crossover though.

Could I possibly damage the speakers running them with a 500hz 24dB LR HP crossover?? Like I said, they sound great and the measured response looks fine below 800hz, but I just wanted to get the input of those with more knowledge/experience. :-) Just curious.

The speaker in question is the 3.5" included in the KFC-XP6903C component set - but the same 3.5" is also available separately as the KFC-X3C.

Thank you.

[xTHANATOPSISx]

There's a couple things potentially at play here. First, frequency response specs given as a range like that are only somewhat useful. They need to specify what the response is like across that range. As in how many dB of variation there is. Sometimes you'll see something like "±5db" after the range which tells you there's as much as a 10dB swing across the range given. If nothing is listed to tell you that, it could be very little or very significant.

Second thing that immediately comes to mind is that power handling is generally dependant on frequency. You have probably seen this with raw drivers where the power handling spec will list one number for full range or dictate that the RMS power is based on having a given high-pass filter enabled, possibly even specifying the slope as well.

So without a frequency response graph it's hard to say if it's just that Kenwood chose a spec for response that was only ±3 dB or if the reliable power handling is just too low below 800hz to trust the average consumer to run it below there. That they use it in that set with an 850hz high-pass makes me think that it might be more of a response issue but you're probably right to guess it's a first order filter and using the 4th order filter you are likely get the signal attenuated enough by the same point that the first order would have. Which is generally expected I'm sure you know. You can often use a lower filter point I'd you use a steeper slope.

As long as you don't hear mechanical noise/distortion from the speaker you shouldn't damage it. It's not the frequency itself that would damage the speaker, it's expecting and demanding meaningful output at a frequency at which the speaker can't deliver it before it hits the mechanical limits of the cone. If it sounds good you should be fine.

[jtrosky]

Thanks - I appreciate the feedback. I just thought it was really strange how every other mass-produced coaxial 3.5" lists FR down to about 80, but these Kenwood Excelon 3.5"'s only listed down to 800hz. That's a pretty big difference! Physically, they seem the same as any other inexpensive, mass-produced 3.5" speaker...

But yeah, they seem to be working great with a 500hz 24dB LR HP filter, so I won't worry about it. :-) The measured response actually seems better (flatter) than the Infinity Reference 3.5" speakers that they replaced (which do list FR down 85hz).

One of lifes great mysteries, I suppose. :-)

Thanks again.

[xTHANATOPSISx]

The measured response actually seems better (flatter) than the Infinity Reference 3.5" speakers that they replaced (which do list FR down 85hz).

Well I'd hazard to guess Infinity is using a much more... flattering specification. It's probably more like ±10dB. It would definitely be minus at the low end.

[Hillbilly SQ]

My guess is since that 3.5" is meant to work together with the 6x9 in the set they probably did some testing with it. Probably just sounded best to them with the 850 6db cross point and the 6x9 meeting it up there knowing it should be perfectly capable. And of course just using a 6db slope cuts cost on the finished product. Actually, I've heard some really good feedback on that set from respectable people that have had ears on them.

[jtrosky]

Yeah, I really do like the Kenwood speakers. For what they are (a $220 set of mass-produced, inexpensive component speakers), they sound really good.

It's funny - I took my old car - a 2012 Impala (now my wifes car) to get pizza the other day since it was pouring down rain and I had just washed the Challenger) and I couldn't believe how crappy the stereo sounded in the Impala compared to the Challenger (full DSP system).

In the Impala, I have older Pioneer D-series speakers all around (which I actually think are decent speakers), but no real DSP - just a Kicker KEY180.4 auto-tuning DSP amp - it has 6.75" coaxial speakers in the doors and tweeters on the a-pillars (facing inwards towards each other). The speaker setup in the Challenger is *so* much better for imaging/staging with the 3.5" in the dash and 6x9's in the doors - it's just *so* much better since the mids and highs all come from in front of you and up higher.

Originally, I was thinking that the speaker setup in the Challenger was less-than-optimal, but I'm realizing that it's actually a pretty good setup for stock-location speakers. :-)

[Hillbilly SQ]

Yup, when done right speakers firing up from the dash can have really good results. My dash speakers are doing 300 and up in my Ram.

[Smitty]

Can you elaborate some more on the sound quality? Maybe compare to other speakers.
I ask because I was looking at that set for my 4runner. I haven't had a 3 way setup for years and liked the idea of the Kenwood setup. Never had Kenwood speakers and curious about the tweeters mainly.
I just came out of a very disappointing run with some JL Audio C2's. Horrible tweeters.

[jtrosky]

I don't have much to compare the sound quality with since I've only had stock speakers, Infinity Reference speakers and now these Kenwoods in this car (2018 Dodge Challenger). I will say this - to me, the biggest improvement going from the Infinity Reference coaxials to the Kenwood component set was the 3.5" speakers in the dash. The Kenwoods just have smoother, more "relaxed" highs - especially at louder volumes.

However, I have only ever used inexpensive, mass-produced speakers from mainstream companies, so I can't compare the Kenwoods to higher end speakers like AudioFrog, Hertz, Morel, etc...

[Smitty]

Thank you. That does help some because I'm familiar with the Infinitys.