Headunit outputs full range to all speaks

We installed a subwoofer in my girlfriend's car, and her headunit only had one RCA output - REAR. So the HU is sending the full range signal to all of the speakers. Sub is crossed over at the amp. Until we upgrade her HU or get a new set of speakers all the way around, would bass blockers solve our problem? Do they allow any midrange through? How do they install?

Thanks!

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You didn't state your probelm. I will assume that your other speakers are distorting from too much bass. Depending on your car and your existing speakers, they may not be great at handling bass of any amount. Bass blockers are simply capacitors that filter out certain sound frequencies. They filter out freq. at 6dB/octave. Different values in caps. will change at which freq. the caps. begin to filter out sound. Yes, they will allow midrange through, as they are primarily designed to start at freq. well below midrange. You need non-polarized caps. They install inline on the positive speaker line to each speaker. The downside to these is that they put the speaker out of phase by 90 degrees. Some vehicles have other solutions so post your vehicle type and system lay out so others can offer suggestions.

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sparky

Yeah, that is the problem.

She has a 2001 Honda Civic EX.
She is using a sony HU with stock speakers (not component, nor coax - just standard).

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Get her a $99 amp and a pair of $49 coaxials.  Will take care of the crossover problem and provide better highs to compliment the new sub install.  (...prices shown are valid only if you are a careful and frugal shopper of discontinued products...;)

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Well, that is my eventual plan! Was just looking for a quick fix for now.

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What is a good crossover value for these bass blockers?

What does being out of phase of 90 degrees actually mean?

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https://www.mhsoft.nl/spk_calc.asp#crossover

https://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=027-370  cheap but effective.

A 250 uF cap on a 4 ohm woofer will start the 6 db / octave slope at about 160 Hz.  But keep in mind that it is 6 db per octave, so the woofer output is attenuated by 6 decibels at 80 Hz.

https://www.the12volt.com/caraudio/cross.asp#hp shows the hookup.

90 degrees out of phase is an "in-between" problem that can't be fixed by reversing polarity on one of the drivers, as an 180 degree out of  phase situation would be.  The cure is to reposition one of the drivers if this out-of-phase issue is a problem.  It would manifest itself as a "muddying" of the sound.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

This is what it would look like if 2 woofers were both out of phase by 90 degrees?

i found this animation.
https://www.sfu.ca/sca/Manuals/ZAAPf/p/phase.html

I'm not quite grasping why adding these capacitors puts the speakers out of phase. Is it because it induces lag? Wouldnt both speakers be lagging by the same amount?

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Phase shift induced by the various orders of crossovers is something I can't explain, because I don't understand it myself very well.  But, suffice to say, if both L and R speakers have the same crossover, they will be identical with no phase shift between one and the other.  Read  2.1 Phase shift vs. time delay in Rod Elliott's site.

The importance of this phase shift phenomemon becomes apparent when designing a two-way or three-way crossover network.  A design program like Speaker Workshop helps me to get the phase rignt in the network even though I"m not sure how...  But anyway, as I understand it, the importance is the phase difference between two or more drivers in the same network (like a component set or simple coaxial)...not the difference between the front pair and rear pair of speakers in an installed system.

Okay, here's an illustration:  say you have a simple pair of coaxials with the 1st order crossover (capacitor) already built in, which helps to block low freqs from the tweeter.  The drivers in that network (the mid and tweeter) are designed to work together with the knowledge that there is a 1st order, 90 degree phase shift, crossover included.  The coaxial will sound just fine if you leave it alone, for what it's worth.  Now, say you want to mess with it...you pull out the cap and replace it with a textbook 2rd order crossover, consisting of a cap and a coil.  The phase difference is 90 degrees per order, so now you have a 180 degree phase shift between the tweeter and the mid, but you haven't made any other changes to the network to compensate for that difference.  The result would probably be less desirable than if you just left it alone to begin with.

(...somebody correct me if I'm whacked out on this one...)

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

There isnt a tweeter on these speakers, just mid-range speakers all the way around.

I dont think that there would be a phase shift if all of these speakers had the same capacitor, do you?

Also, where is a good cutoff freq for these mid-range speakers?
HPF @ 150-200 Hz?

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There will be a phase shift. You can't change the laws of physics. I would suggest about 200 Hz as the 6dB/ocatve fall off will eliminate the deep bass giving the speakers the problem. Caps. are fairly cheap, but shop around. You may get a good price from an electronics supply store. You might just be better off leaving the bass level at the middle level and save for new speakers. Buying caps for each speaker may cost as much as half a decent pair of speakers. You may want to check that your sub is giving all it can as it is designed to give you the bass you want. If the amp, or sub box isn't correct, you could be missing out on the bass you are looking for without overdriving the rest of the speakers.

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sparky

I think that if I adjust the sub amp it would overpower the other speakers.  At low/moderate volumes everything seems in harmony, but as you turn it up - the speakers begin to cause rattling in the doors and eventually some distortion.

Those capacitors previously linked were less than $3 a piece. 

Radio shack has these:
https://www.radioshack.com/product/index.jsp?productid=2103623&cp=2032058&pg=3&f=Taxonomy%2FRSK%2F2032058&y=8&categoryId=2032058&x=7&kwCatid=2032058&kw=capacitor&s=D-StorePrice-RSK&parentPage=search

Which would start the crossover at about 180 Hz. 
That will work, right? 

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So I'm still a bit confused. The speakers will be out of phase due to time delay?

Will they only be out of phase in relation to the subwoofer?

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The capacitors will throw the signal off by 90 degrees in theory.  So yes, the phase will differ with the subwoofer, but experimentation with positioning can help you if you notice a difference.  You may notice something sounds a little different, but can't quite pinpoint the source.  If so, it may be a phasing issue which can many times be much improved by moving the enclosure elsewhere.

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My ex once told me I have a perfect face for radio.