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Managed great sounding invisible install!!

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  • Managed great sounding invisible install!!

    I've managed to install some speakers in the original dash cut-outs and a little sub behind the glove compartment and even without an external power amplifier it rocks extremely well!!

    for my daily job I work as an engineer in broadcasting electronics, pro video cameras and my specialty is audio. I've been involved in development in audio equipment from since I was a kid as my father was an engineer for Amroh, Wharfdale and BNS. I've always had measurement equipment to my disposal and I have a pretty good set of ears. My specialty in speaker design is creating super small systems with super large sound. I used to calculate everything by hand back in the days, but nowadays you can get really great free software.

    In cars it is a custom to not use an enclosure, so all car speakers are designed to work in a huge variety of super leaky super bad or non existent enclosures. Which is why they are never superb performers, even if you would want to put them in an enclosure, when you would calculate a proper one if you managed to get your hands on the parameters you'll see that even small drive units want huuuuuuuuuge boxes. If it gets any smaller linearity is compromised and the speaker will start to vastly exaggerate certain frequencies.

    So, the real proper approach to car audio bliss is to implement a real enclosure and use hifi drive units instead. And when you are really good and experienced you will be able to see in the blink of an eye whether the parameters of a certain drive unit make it suitable for your application or not. In this case I have been shopping around for speakers that don't have any complex demands in terms of filtering and can work in super tiny enclosures. I wasn't looking for an earthquake machine, but just really proper tight and realistic music reproduction.

    After making some orders and creating some small speakers I have decided to go with the Fountek FR88EX fullrange driver to place in the dash, but placed these in a 90 degree PVC rainwater drainage pipe bend with a little piece of tube sealed with a cap. This resulted in a less than 1 liter enclosure that fitted right in place in the original holes under the original grilles.

    Then I wanted to add a good dose of low end, and managed that with the Monacor SPH-4TB. There are several more very suitable candidates though, all with some slight benefits and down sides. Creating audio systems is always done by choosing the combination with the least down sides, it is always a compromise of some kind, no matter how much effort and money you'll throw at it. You can not bend physical laws. When I started calculating with these woofers I was rather surprised at the amazingly small enclosure this resulted in, first results ended up in an enclosure barely larger than 1 liter! That was with a 51cm long bassreflex port though. I finally did some calculations with the series resistance that they were going to see from the passive filtering I planned for them, that resulted in a calculated enclosure of 2.2 liters and with the huge 30mm 51cm long port that ended up in a roughly 4 liter large enclosure. I also chose PVC pipe for this as there are fantastic adapter pieces available from 120mm to 35mm, which was very usable to fit the port in. The subwoofer has a similare shape as the little satellite boxes, but just a size larger. It is small enough to fit behind the dash completely.

    I'm planning to shoot some pictures some time soon, but the guts of the system aren't exactly lookers, it just sounds absolutely stunning!!

    If any of you are planning a system or want something that is completely concealed feel free to ask me more details you may wish to know about such a system.

    Some systems I've made:





    The heart of my system are the fullrangers and are based on these speakers which I have designed too.
    http://www.diyaudio.com/forums/full-...fr88-ex-8.html

    Here's how they measure without sub:

  • #2
    Re: Managed great sounding invisible install!!

    nice

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    • #3
      Re: Managed great sounding invisible install!!

      Nice work. I'm into loudspeaker, amplifier and electronics design too. I was looking at the FR88 a while ago.

      I take it you are stuffing the pipes? How come you are using a passive filter when reasonable headunits have filters these days?

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      • #4
        Re: Managed great sounding invisible install!!

        Nice work. I'm into loudspeaker, amplifier and electronics design too. I was looking at the FR88 a while ago.

        I take it you are stuffing the pipes? How come you are using a passive filter when reasonable headunits have filters these days?

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        • #5
          Re: Managed great sounding invisible install!!

          Originally posted by richie00boy View Post
          Nice work. I'm into loudspeaker, amplifier and electronics design too. I was looking at the FR88 a while ago.

          I take it you are stuffing the pipes? How come you are using a passive filter when reasonable headunits have filters these days?
          Thanks guys!

          Well I had this headunit and already have a huuuuuuge crate of filter coils caps and resistors, so I just hacked this filter together for now. I planned on building a four channel amplifier with active filters sometime soon. I already designed and tested a switchmode DC-DC converter that can do up to 1.5 kilowatts, which is a 10x10cm board with small toroidal transformer, running on 35khz. That will be combined with a four times 100W 24V amplifier. So the DC-DC converter will be 12V in and around 60A max. draw, and +/-15V out for the filters, 24V out for the amplifier. It'll be around 18x10x3cm size when finished.

          I've built many more of these amplifiers, but somehow they always soon find a place in somebody elses car.

          Also, this system I built to prove how low profile, small and cheap a system can be still outperforming most very expensive car audio systems. You can design a speaker to perform in just about any cardboard cut-out, but you can never beat one with it in a real enclosure. And as said, car speakers are really bad performers in an enclosure, you really need a hifi speaker driver design for that. So best leave the gold plated super spiffy red coned drive units with texts printed on them like BOOOMBLASTER or US SUPER BOOM BOMBER alone and buy some decent hifi drivers. And when paired with a good amplifier with DC-DC converter even 8 ohm drivers are very suitable, and will always perform with much lower distortion.

          I did stuff the pipes with a little synthetic wool. The satellite speakers are sealed, but the subwoofer is ported. The 3 liter design needed a 52cm port to tune it nicely low, so to fit that in I had to bend it. So I took the heat gun and three bending springs and made three 180 degree bends in it.

          I'm planning on doing some measurements in the car with my system and see how the curves look.

          PVC pipe is so nicely resonance free due to the round shape, even though it is very thin walled. Plus it is cheap and very easy to work with creating a good enclosure in a matter of minutes. The things you can do with a little PVC pipe, some tools and a little brainstorming!

          Last edited by Vinci; 30-08-2013, 10:44 AM.

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          • #6
            Re: Managed great sounding invisible install!!

            nice work

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