[cheshiref1]

Hello all - i have been lurking here a while, but not posted. Absolutely great forum with fantastic advice. Thanks!!!

So, after reading around, i have decided to upgrade my Audio. Car is UK E91, 320d M-Sport with a Re-Map. Standard-fit Professional Stereo and BT phone kit.

Done a fair bit of research and i have a limited budget at present (2 house purchases going through - stress!!??? AAARRRGH! ). So, i have come up with the following:

1. Upgrade front speakers to Innfinity Reference 47.2i - these are multi speakers, so the tweater is within the unit, but they still use a separate Crossover to split the feed. Strong Voice Coil rated at 50W RMS.

2. Upgrade 2 x under-seat subs to Earthquake SWS-8, 150W RMS (direct-fit, hopefully!).

3. Install Pac-Trunk Loc for Low Level feed and remote amp wire.

4. Leave factory-fit amp to drive the rear speakers (with reversing sensor alarm)

5. Drive 2 x Subs with a Monoblock AMP, running 2 Ohm Stable. (Either a JBL 301.1, or a West Coast 5001). Output at 2 Ohm is 150W RMS - perfect match for the Earthquake Subs.

6. Drive 2 x Infinity Reference speakers with a 2 Channel 50W RMS amp (possibly a Vibe BlackBox I).
Having spent some time on a few vehicles in the past tuning the gain / audio levels etc. i look forward to doing the same again to squeeze the best out of the setup.....

Present prices that i can get these parts at means an install of circa £420.

Be very interested to hear in your Thoughts / Ideas / no-no's??

Cheers!!

[E92Fan]

Within your budget, I think you have chosen well. Although you might want to consider buying a much higher-quliaty 4-channel amp like a DLS Classic CA41 (which is around £265) and run the fronts of 2 channels, and bridge the other 2 channels to give a high power mono output. This maks the installation neater, and the sound quality in my opinion will be much higher as the Infinity's will be amp-ed by something a lot more audiophile than a Vibe Blackbox. Also the DLS can accept a high-level input so you don't need to run the PacTrunk, and also the DLS has autostart off the high-level inputs so you don't even need a remote wire! The DLS has full crossovers too, so getting the balance between the fronts and subs will be fairly easy (I reckon a crossover point at around 130hz will do it)

You'll need to do a tiny bit of modding for the Earthquakes, but nothing major, and yes they do fit quite easily.

If you need more direct help, PM me. I'm based in London..

[cheshiref1]

Thanks for the advice E92 Fan......

I had thought of a single AMP driving the whole system, but i was worried that most 4-channels with a decent output have too high an RMS rating to drive the (small) front speakers.

Am i worrying over nothing here? I.e. can i balance the system to make sure i dont blow the fronts at a high volume?

PS - i already have the Pac Trunk-loc, so might as well use it! I'll go research that amp / similar ones to it.

Thanks again!

[E92Fan]

Don't worry about the RMS rating being too high - it doesn't matter actually. In even loud running the amp is only delivering a few watts maximum to the speaker - the higher RMS rating just means that the amp has power in reserve, so it generally will sound more effortless and will be able to deal with the peaks and troughs in sound level more easily.

I personally wouldn't use the Pac Trunk thing because there's no point converting the high-level signal from the head unit into a low-level signal, then back out again for the speakers. You are likely to get more interference in the low-level signal as well. The only benefit in going low-level is if you are going to use a DSP processor in-line, but then that will cost you an extra £300 or so, for not much gain in your proposed system.

[E92Fan]

Oh and incidentally, you may want to consider buying a set of 4" components and not co-axials.. You can get the spare mirror-mounting part from BMW for £30 or so (for both sides). That way you can place the tweeter in the standard Hi-Fi location and it still looks completely stock. The sound quality will be miles better too.

[cheshiref1]

cool - i see!!

Looking at that AMP spec, it runs 4 x 70W RMS. I have done a load of reading around and many amp manuals say NOT to bridge up to 2 Ohm (i.e. not bridge the 2 x Earthquakes) - is this what you are suggesting, or simply stick to running the subs from the normal 4 Ohm channel, pumping 70W RMS into them?

Thanks again - i take your point RE the Pac-Loc...... I suppose it replicates what the DLS does with a same signal anyway.

[cheshiref1]

Well, a quick bit of further digging on the 'tinterweb and the CA41 will not run Bridged 2 Ohm (i.e. 2 x 4 Ohm speakers)....

BUT....

The CA31 will

A rapid trawl on the net found their site (www.dls.se) and i found a few retailers - same cost as a CA41 (c. £250 - 270). As luck would have it, there was a single solitary item on eBay throughout the World. Last of the 'classic' line and £90 off!! Yep, i just bought a CA31 for £180.

So - thanks to the advice of E92 Fan i will now be running a pretty neat system. And a higher quality sound too.

I will be 'collecting' the bits for this over the next couple of months and doing the install once i move into my new place (round Xmas fingers crossed!). Will keep you all posted.

Cheers!!

[E92Fan]

Right, if it were me, I'd run the Earthquakes as two separate left and right channels, off a 4-channel amp with the fronts powered via the other two channels.

The reason why is this - the Infinity's technically drop to 75Hz in an anechoic chamber, but this is 12dB down from reference point. In the real world situation of it being sited in your door, where there is no genuine loading on the driver, you will find that the speaker will actually start rolling off from about 135Hz or so - ie. from frequencies of 135Hz and below, it starts getting quieter and quieter, until below 75Hz you can't really hear anything. Standard audio CD reproduces a frequency from 20Hz - 20kHz.

You will use the Earthquake subs to fill in the frequencies below the 4" coaxials in the doors - however because the subs will probably have to start quite high up the frequency range (ie. 140Hz or so) your ears will still be able to localise the stereo image in the bass (it is assumed that below 100Hz it becomes very difficult for the human ear to separate a stereo image)

That is why I would treat the Earthquakes more as woofers than subs, and run them in stereo to extend the bottom end of the 4" speakers in the doors. You will still get extension down to 20Hz or however low the speakers go, but I think you will get a slightly better sound that running the two subs in mono, off a bridged output.

(incidentally, the amp is fine running at 2Ohms as it is rated 2Ohm stable. Some amps are NOT stable at 2Ohms so you wouldn't be able to bridge the two subs into mono)

And incidentally, you could consider the Classic CA31 which is a 2+1 amp, which will definitely drive the Earthquakes. Will still give you a great sound, but you'll have to be more careful about choosing the crossover points between the mids and subs. You might want to Dynamat the front doors to give a little more reinforcement to the mids, and then you'll be able to crossover a little lower - say at 110Hz, which would negate the concern I have about stereo imaging. The Dynamat will cost you all of about £30 to do... worth it IMO in this case.

[E92Fan]

Oh, and I've just seen you've bought a CA31.. !! Nice one...!

PS.. the CA41 can run 2 + 1 bridged into 2Ohms stable... I used to do that in my previous car

[cheshiref1]

Originally Posted by E92Fan

Oh, and I've just seen you've bought a CA31.. !! Nice one...!

PS.. the CA41 can run 2 + 1 bridged into 2Ohms stable... I used to do that in my previous car

hi mate - yea, i read the tech specs etc. and a few forum posts about the CA41 and bridged 2 Ohm on the other channels isnt advisable. Like you say / have proved, i am sure its fine anyway (quality built amp) !!!

But, good deal got on the 31, so we will wait and see. Looks a pretty amp (proper old skool all heatsink design, no fancy crap!!) I like that, so will keep it on display - also better for cooling.

Thanks again - oh and good luck with the e92 when you get her back!!

[E92Fan]

Originally Posted by cheshiref1

hi mate - yea, i read the tech specs etc. and a few forum posts about the CA41 and bridged 2 Ohm on the other channels isnt advisable. Like you say / have proved, i am sure its fine anyway (quality built amp) !!!

But, good deal got on the 31, so we will wait and see. Looks a pretty amp (proper old skool all heatsink design, no fancy crap!!) I like that, so will keep it on display - also better for cooling.

Thanks again - oh and good luck with the e92 when you get her back!!

Thanks buddy. Hope the car works ok!

You'll love the CA31 - the build quality is fantastic and you're right, it's proper old skool style. Just make sure you give it enough ventilation, especially if you mount it upside-down (which you're not supposed to)

Enjoy the install!!

[Technic]

Originally Posted by cheshiref1

3. Install Pac-Trunk Loc for Low Level feed and remote amp wire.

Is this Pac Trunk-Loc a differential input capable LOC?

[E92Fan]

No, it's a very basic LOC, accepting only standard speaker-level inputs from inbuilt amplifiers outputting a maximum of 80W. S/N Ratio is pretty poor, has an in-built subsonic 20Hz roll-off filter at 6dB slope (which is slow) and shouldn't be used IMO!! Only outputs 2V line-level, which is massively susceptible to interference.

If you need a line-converter that accepts differential inputs, better get an AudioControl unit like the 2ch Overdrive or 6ch Matrix, which will output line-level at up to 13V maximum, which will reduce interference along the low-level signal. Or the new Rockford Fosgate 360.1 or 360.2 DSP units, which do the same thing but add advanced DSP control to the signal.

[Technic]

Thanks, that's what I thought.

My question about that LOC is based on where the OP wants to connect it... if it is in between the OEM HU and the OEM amp then it will not work; if it is after the OEM amp then it will.

[E92Fan]

Originally Posted by Technic

Thanks, that's what I thought.

My question about that LOC is based on where the OP wants to connect it... if it is in between the OEM HU and the OEM amp then it will not work; if it is after the OEM amp then it will.

In the UK, the standard audio setup in the E9x has no external amp - the amp is built into the head-unit. In the US, you have what we call the Hi-Fi setup, with separate tweeters and mids in the front, and an external amp.

[Technic]

Originally Posted by E92Fan

In the UK, the standard audio setup in the E9x has no external amp - the amp is built into the head-unit. In the US, you have what we call the Hi-Fi setup, with separate tweeters and mids in the front, and an external amp.

I knew that too... in this case, the OP audio system looks to be the HiFi:

4. Leave factory-fit amp to drive the rear speakers (with reversing sensor alarm)

[ianbiz]

I think some CDT 8in subs would sound a little cleaner in there. I have heard some of Earthquakes before, and they aren't the cleanest sounding subs ever.

Do you plan on rebuilding the "box" or just reuse the OEM ones?

[Technic]

Originally Posted by ianbiz

I think some CDT 8in subs would sound a little cleaner in there. I have heard some of Earthquakes before, and they aren't the cleanest sounding subs ever.

Do you plan on rebuilding the "box" or just reuse the OEM ones?

The CDT website doesn't show any shallow 8" subs...

[italiano1980]

Just to reply to what someone said earlier. RMS is extremely important. If you have a speaker that can handle 50 watts RMS then you want an amp that puts out 50 watts RMS. You always want to match up the RMS if you can. If you can't, then you are better getting an amp that puts out a little less RMS than the speaker. If you go over, it won;t sound right. Max power is different. That just tells you what a speaker can handle or a amp can put out during an instantaneous burst of power. That has been my experience.

The infinity reference series speakers you want can handle 35w RMS. The kappa series can handle 50w RMS. If you do get the reference, i would not even bother with an amp because the stock bmw amp puts out about 25w RMS at 2ohms. Also, infinity speakers seem to be very efficient, so they should sound good even with little power going to them.

[Technic]

Originally Posted by italiano1980

Just to reply to what someone said earlier. RMS is extremely important. If you have a speaker that can handle 50 watts RMS then you want an amp that puts out 50 watts RMS. You always want to match up the RMS if you can. If you can't, then you are better getting an amp that puts out a little less RMS than the speaker. If you go over, it won;t sound right. Max power is different. That just tells you what a speaker can handle or a amp can put out during an instantaneous burst of power. That has been my experience.

The infinity reference series speakers you want can handle 35w RMS. The kappa series can handle 50w RMS. If you do get the reference, i would not even bother with an amp because the stock bmw amp puts out about 25w RMS at 2ohms. Also, infinity speakers seem to be very efficient, so they should sound good even with little power going to them.

That's just not true.

The issue is tuning the amp gains to your system/speakers, as even a low power amp can sound crappy without tuning, and asking too much from a speaker regardless of the power rating will also sound crappy. Of course, we are not talking about feeding 200w RMS to a 50w RMS speaker. Of course, following the RMS rating is the best solution, but again at the end of the day you have to adjust the gains and any crossover points available anyway. And as such, 75w RMS, even 100w RMS to a 50w RMS speaker will sound as great at 50w RMS as long as you tune that amp/crossovers.

I'm feeding right now 200w RMS to a sub that is rated at 175w RMS and the sucker sounds great. Used to feed the same 200w RMS to another sub rated at 125w RMS and the same thing: sounded great.

[E92Fan]

Originally Posted by italiano1980

Just to reply to what someone said earlier. RMS is extremely important. If you have a speaker that can handle 50 watts RMS then you want an amp that puts out 50 watts RMS. You always want to match up the RMS if you can. If you can't, then you are better getting an amp that puts out a little less RMS than the speaker. If you go over, it won;t sound right. Max power is different. That just tells you what a speaker can handle or a amp can put out during an instantaneous burst of power. That has been my experience.

The infinity reference series speakers you want can handle 35w RMS. The kappa series can handle 50w RMS. If you do get the reference, i would not even bother with an amp because the stock bmw amp puts out about 25w RMS at 2ohms. Also, infinity speakers seem to be very efficient, so they should sound good even with little power going to them.

Man you can't be more wrong. The RMS rating of a speaker is essentially nonsense, as in normal conditions an amplifier is only producing a few watts of power, at most. It's when you get sudden peaks in level that the current and power starts increasing - if your amp is under-powered, it will reach clipping point a lot faster and run out of steam quicker, thereby increasing distortion massively and will lead to broken speakers. Having a 500W amp going into speakers that can handle 100W RMS is absolutely fine - and more often than not recommended, as for sure a 500W will be able to have the current-delivery capable to drive demanding speakers and to control the cone movement well.

To say that on for the Kappa speakers rated at 50W you should only go for an amp a few watts less in power is completely inaccurate and unhelpful to those who are seeking good advice.

[italiano1980]

I apologize if I have misinformed. This is the advice many people have given me over the year.