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Big Megger
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238 Posts
Discussion Starter · #1 ·
I thought I should point out to people intending to change their existing speakers for ones with separate tweeters that there is a fundamental flaw in this.

I have been doing audio installations for a long time now and have been designing sound system including custom amps for musicians for the past 16 years and despair at some peoples choice in speakers. Most people are now aware of the difference in the stated MAX output from a speaker and the RMS. They have also got to know about frequency response, but this is not the only thing that should be taken into consideration when designing systems. I know that the manufactures of speakers go well into the depth of the Theile/Small Parameters, so that the best enclosure or free space can be calculated.

Where I am going with this is that if you get yourself a standard pair of separates and put the tweeters up on the dash and the squawker/bass speaker down low you might as well not have the tweeters in at all.

The reasoning behind this is that sound coming out of the head unit is made up of multiple frequencies.
The lower frequencies are felt more than heard and that is why you can install the sub woofer in the boot. They can travel larger distances and are harder to deflect. These frequencies travel at the lowest speed of the sound range.
The high frequencies are very much directional and should face in the direction of the listener. They can travel short distances and are easy to deflect. These frequencies travel the fastest of the sound range.
The mid range frequencies bridge the gap between the high and low frequencies and carry the bulk of the audible sound. These do not generally require to be directed at the listener but should be if possible.

Now installing the cheaper end of the market (lets say things that sell a lot because they are bright green) have a standard main cone that covers the upper half of the bass range and the mid range. They also have a separate hi range tweeter that is normally installed somewhere in the dash or high in the door. They also rarely have a cross over unit in them which will divert only the high frequency sound to go to the tweeters, which if not in place will cause distortion to the output of that speaker. Putting the two speakers in this configuration also causes a phase lag to the listener. Which means that the sound coming out of the tweeters will hit the ear before the sound coming out of the other speakers. Now I know everyone is not an audiophile and demand true sound but you could quite possibly be ruining the sound quality from your system just because you got the fancy looking speakers.

My advice to people looking to replace their speakers with, lets face it better ones than the standard fitted by ford should look for ones that have the tweeter fitted in the cone and if possible ones that can change the direction of the tweeters.

With this you will minimise the phase lag and have a better resemblance of the true sound.

I will admit that people have different taste in music and hw they want to hear it but I assure you that you will get a better sound doing this
 

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Little Megger
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7 Posts
Whilst i see your point to some extent i think you are going "by the book" and not dealing with things in the real world.

There are several assumptions you have made, of which i would like to address one by one.

Firstly, as you assert a coaxial/point source driver is the ideal situation for the home/professional market. Obviously in a room the drivers can be alligned in such a way as to allow all the sound to come from one point.

Secondly, whilst this is true you seem to think that this bears any resembelance to a car. For a start you need to consider aiming of the drive units and whether in the OEM door positions the tweeters can give anything resembling a soundstage or a stereo image.

Thirdly it appears to have completely passed you by that most component kits now include crossovers which allow you to run attentuation to your tweeters which will negate the effect you are discussing (which is not frequency dependant but distance dependant).

Fourthly - 1 word - ACTIVE (can get 3 way onbard on a £199 alpine)

Fifthly - 2 words - TIME ALLIGNMENT (can get 6 channel DSP time allighment on a £199 alpine)

Sixthly - if fancy electronics are not the way - if people carry passengers regulalry you NEEd the tweeters outside the line of the legs etc as the short wavelength sounds get killed by peoples limbs in front of them.

Seventhly - AIMING - if you aim the tweeters at the screen it lenghtens the effective path and minimises this approach.

May i ask how many competiton standard CARS you have built, whether you have competed in any Sound off leagues/won anything?

I.E. do you have the rights to stand there and say what you did............
 

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MEG Sergeant
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1,145 Posts
Damn, you say we should all be using coaxials as component sets down come with a crossover. Well I dont know of a set of components that dont come with a crossover, even the really cheap ones and come to mention it, the ones that are green ;) The company that make the green ones do expensive ones too that are actually quite good.

As for coaxials, Ive never been able to achieve a decent image or soundstage with themm adjustable tweeters or not. I understand what youre getting at with the frequency wavelengths but its often impractical to have the tweeter ontop of the mid.

Just a thought, Ive never seen an IASCA or EMMA competitior use a pair of coaxials either :whistling:
 

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Registered
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105 Posts
Batdragon - I am trying to think of a more polite way of putting this, but to be perfectly honest, you're talking cráp.

Different drivers have different responses, yes...and if you're REALLY fussy, you can flip the phase of the tweets, which can make a difference too.

I have run coaxials before, and I have run components - putting some time and effort into CORRECTLY installing and setting up a set of component speakers will allow much more versatility in terms of mounting, aiming etc.

The only point you do make which is correct is path length. Ideally, your mids and tweets should be roughly equidistant from your ears, which is why people sometimes mount their tweets in the footwell, aiming up - as this gives a nice high sound stage. However, considering where your head sits in the cabin airspace, it is comparatively easy to obtain a similar path length between your ear and the midbass speaker (in the door) and the tweeter (on the dash) if you should wish to do so. Left-to-right is more of an issue, but you can either flip the phase of the right hand components to introduce a slight mechanical delay, or you can use the time alignment function of certain HUs / processors to do this for you.

Yes, having tweets on the dash can introduce problems - rainbowing, and the strange sensation where vocals seem to move around in front of yo, but a bit of fiddling with the XO points can soon solve this.

But advising people to ditch components in favour of coaxials, which are almost always cheaper (due to the lower quality componentry and the much more simple XO design) is a no-brainer.

Get components into your car if you want decent sound. Coaxials work, but you should only use these if you're on a serious budget, or if you're lazy!

B
 

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Big Megger
Joined
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238 Posts
Discussion Starter · #5 ·
I was going to write a long-winded explanation on my viewpoint that I put in the original post, but could not be bothered. I admit it was overcomplicated for the point I was trying to make. What I will say is fair shout for being committed enough to post back, though Benny79 you should think a bit harder of a way of putting that :whistling: :D

Something to remember is that if you look at the majority of posts in this forum it is asking whether a 6x9 would fit in the door? Most people do not have the time or money to set the best speaker option if they did organisation like IASCA and EMMA would not exist because we would all have something extraordinary in our cars. They just want advice on what is out there on a budget that will be better than what they have. Places like Halfords (not to single them out) sell a huge amount of audio kit, which is usually better than factory fitted stuff, but not even close to competition equipment

Troublemaker said I was not in the real world and going by the book. This is true to a point. I was not aiming this at the high end of the spectrum but at, as I said before people who are looking to replace their factory fitted 5x7, I just over complicated it.

I have written three white papers on sound and sound projection in enclosed spaces, and by far the worst to do was to try getting 50 people in an auditorium and getting the sound set up so that each one would hear a different audio commentary than the person sitting next to them. Now that was a hard set up.
 

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105 Posts
Okay, I admit that was maybe a little harsh :D

However, I've heard many arguments "for" and "against" coaxial drivers - I've used several sets of both in the past, and i've always found components to be a better bet all round.

Yes, there is some overlap. A high-end set of coaxial drivers will perform as well as a low end set of component speakers, however I stand by my original point.

Coaxial drivers are fine if you're running from an OEM HU. Maybe even from an aftermarket HU if you're not fussed about sound quality, but this is because they're designed for this purpose - typically having 1W/1M sensitivities 3-6dB higher than the equivalent component set, because they need to perform well from the comparatively low (5-15w RMS) output from a HU.

As soom as you start getting amplifiers involved, the additional sensitivity goes out the window, because you have much more power to play with, which gives a more controlled (as it's the coils controlling the speaker movement as opposed to mechanics) and a more dynamic response.

And I'm taking from the original post that the sort of people who are "into" their car audio enough to care about rainbowing, off-axis response and path lengths are more likely to splash the cash on a decent amplifier in the first place.

Also, from the original post - high frequencies should not always face the direction of the listener. Even attenuated, some tweeters can appear too piercing, so a common trick - as you'll no doubt know - is to configure the tweeters up to fire across the dash...a so-called "off axis" response. I've found this allows you to run the tweets with enough power to let them sparkle, but not to deafen you.

I also disagree with your analysis of sub-bass frequencies - anything which would be played from a subwoofer (i.e. sub bass...20-80Hz) is non-directional, but the statement that "The lower frequencies are felt more than heard and that is why you can install the sub woofer in the boot" - fundamentally incorrect. Yes, you can feel the frequencies - but the human hearing range is perfectly able to hear these frequencies, and their harmonics too. The reason subs are usually boot-mounted is because they require enclosured in which to operate (unless IB), and not many car cabins can sacrifice the room for a large woofer box.

The mids of a component / coaxial set should really only be playing 50Hz and up. More commonly you'll see 80Hz or even 100Hz and upwards from the mids, but sound above the 150Hz mark IS directional, so yes - I do feel that you can see gains by aiming your mids, even though most people don't bother.

You can also lose the effect of rainbowing by changing the crossover points...something that can be done easily by setting a jumper inside a passive crossover box.

If you just want to uprate your stock speakers, then fine - go coaxial. But if you want a significant increase in sound quality...it's got to be components every time.
 
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