[BEM-S4]

Will post a detailed write-up at some point but I worked with Technic and it is now possible to upgrade your amp and keep the OEM stock amp connected as well for CAN bus, in case the dealer ever needs to update the SW in your car. My F31 now has three amps:

1. Bimmertech for audio
2. JL for subwoofer
3. Stock HiFi for CAN bus only

They are all installed all the time, so there is no need to swap anything out for trips to dealer. Install was pretty straight forward, we added some wires to the Bimmertech connector. If you are using Technic harness instead for another type of amp, you may be able to get everything in one harness - but he can chime in there.

[IK6SPEED]

Originally Posted by BEM-S4

Will post a detailed write-up at some point but I worked with Technic and it is now possible to upgrade your amp and keep the OEM stock amp connected as well for CAN bus, in case the dealer ever needs to update the SW in your car. My F31 now has three amps:

1. Bimmertech for audio
2. JL for subwoofer
3. Stock HiFi for CAN bus only

They are all installed all the time, so there is no need to swap anything out for trips to dealer. Install was pretty straight forward, we added some wires to the Bimmertech connector. If you are using Technic harness instead for another type of amp, you may be able to get everything in one harness - but he can chime in there.

I do not have enough room for all the amps I want in mine, much less extra ones, lol.

[pyakoub]

I have weird voice comes out the speakers but not all the time and not with all the songs , like the song is playing good and the bass is perfect but there is something comes out like a whistle! Anybody know what is that ?

[IK6SPEED]

Originally Posted by pyakoub

I have weird voice comes out the speakers but not all the time and not with all the songs , like the song is playing good and the bass is perfect but there is something comes out like a whistle! Anybody know what is that ?

Poltergeist

[loc2000]

Originally Posted by Billfitz

Probably not. Contrary to advertising claims the OEM speakers are quite good. Where some improvement can be had is in the low frequency extension of the under seat woofers, but only if the amplifier power is significantly boosted.

Do you know whether hifi amp sends full range signal to mids/tweeters? My Gf got me focals es100k last night. there come with crossovers with the switch full range/hipass. not sure which setting to use

thanks in advance

[Billfitz]

The Hi-Fi amp has separate amp channels for the under seat woofers and the mids/tweeters. The woofer amps are low passed, the mids/tweeters amps high passed.

[loc2000]

Originally Posted by Billfitz

The Hi-Fi amp has separate amp channels for the under seat woofers and the mids/tweeters. The woofer amps are low passed, the mids/tweeters amps high passed.

So I assume that focals crossover for midrange should be set on full range once signal is already high passed?

[Billfitz]

I would think that full range would mean when they're used without a separate woofer or sub.

[Onizukachan]

It won’t matter, pretty sure the high pass on those is at a much lower frequency than the OEM 175hz highpass, and probably only 6-12db. At worst and at best, you will have Steeper rolloff once you get down to the aftermarket crossover point. But you are unlikely to have enough volume at that point to hear the difference.

Me, I’d run them full range and fuhgettaboudit.

[loc2000]

Originally Posted by Billfitz

I would think that full range would mean when they're used without a separate woofer or sub.

Sorry to bother you but I dont quite understand. Once hifi amp sends signal to speakers (to crossovers first in my case) which is high passed as you said and then when I set crossovers on high pass too, this will mean I high pass it again trough the crossover. Is the signal to my mids not gonna end up being filtered twice (from the amp and then crossovers)?
Is that not gonna affect sound quality?

[loc2000]

Originally Posted by Onizukachan

It won't matter, pretty sure the high pass on those is at a much lower frequency than the OEM 175hz highpass, and probably only 6-12db. At worst and at best, you will have Steeper rolloff once you get down to the aftermarket crossover point. But you are unlikely to have enough volume at that point to hear the difference.

Me, I'd run them full range and fuhgettaboudit.

Makes sense but I thought double filtering would have negative impact on sound quality, what u think?

[Onizukachan]

It won’t.
I used to double stack the amp crossovers with the speakers crossovers all the time back in my serious days. Mostly because amps didn’t have very aggressive crossovers back then, maybe 12db/octave, and an extra 6 in the speaker crossover was great for protecting them from a bunch of 20-30 hz sine waves in bass mechanics test sections... and Tocatta in D.
There is some minor phase shift that occurs when running a passive xover in the configurations speaker crossovers you are talking about use, but there’s a bunch more phase shift when reflected off glass too.. and no one puts curtains on their windscreen and drives around.

The thing is that now xovers are often 24db/octave or more... & you jsut don’t need a steeper slope. That’s why I suggested full range.

[Onizukachan]

To answer your question to bill above,
If the high pass were 6 dB/octave at 100hz, you get 1/4 volume at 50hz and 1/16th volume at 25hz. Just give some really terrible explanation.
It’s not a filter, it’s a volume decrease.

[Billfitz]

Originally Posted by loc2000

Makes sense but I thought double filtering would have negative impact on sound quality, what u think?

Not at all. It just cascades the filter slopes, so you get a steeper cutoff, which is usually a good thing. It allows running the driver to a lower frequency and/or playing louder without excessive excursion that creates high THD. The passive would only be detrimental if its knee frequency was too high.

The thing is that now xovers are often 24db/octave or more... & you jsut don’t need a steeper slope.

I measured the output of my midranges and the rolloff isn't steep, so by no means is the filter high order. If the amp did have at least 3rd order filtering then I'd run without the passive, but it doesn't.

It’s not a filter, it’s a volume decrease.

A volume decrease/attenuation is what a filter does.

[loc2000]

Originally Posted by Billfitz

Not at all. It just cascades the filter slopes, so you get a steeper cutoff, which is usually a good thing. It allows running the driver to a lower frequency and/or playing louder without excessive excursion that creates high THD. The passive would only be detrimental if its knee frequency was too high.

I measured the output of my midranges and the rolloff isn't steep, so by no means is the filter high order. If the amp did have at least 3rd order filtering then I'd run without the passive, but it doesn't.

A volume decrease/attenuation is what a filter does.

Thanks for your reply. Im not an expert on car audio plus english isnt my first language so apologies for confusion. I just wasnt sure if to use high pass or full range on crossover. I wont have time to take door panel off 10x and test crossover settings so I thought someone like you guys would know

Thanks for your time

[Billfitz]

One thing you haven't mentioned is the knee frequency of the high pass. I wouldn't want it higher than 125Hz. There's no problem testing it because the door panel doesn't have to be in place to do that.

[Onizukachan]

Apologies that I misread he was not using the factory amp, when he is. In that case turn the xovers on.

[loc2000]

Originally Posted by Billfitz

The Hi-Fi amp has separate amp channels for the under seat woofers and the mids/tweeters. The woofer amps are low passed, the mids/tweeters amps high passed.

Hello again,

I have installed them focals. Ive set passive crossovers which comes with speakers on 0db for tweeters and they sound fine.
For midrange I set it on highPass (hiPass/fullRange switch on crossovers) and I tested em on various frequencies.
I have noticed that whilst I play test tones of around 300hz and bellow volume decrease is significant (250hz I can clearly hear rear stock speakers more than front focals). That indicates that crossover point of factory amp is lower than passive focal crossovers .
Shall I switch passive focal crossovers on full range in this case and let factory amp to attenuate midranges at lower point than passive do ? Or its just a matter of taste?

Thanks

[Billfitz]

If you're losing output below 250Hz then you're going to have a response hole between where the under seats are working and the mids are working. That wouldn't suit my taste. Try them full range, see what happens.

[Johnny Chuttz]

Originally Posted by Billfitz

The Hi-Fi amp has separate amp channels for the under seat woofers and the mids/tweeters. The woofer amps are low passed, the mids/tweeters amps high passed.

Is the subwoofer signal bandpassed or have a subsonic filter on the HiFi sys? I can't seem to find a concrete answer. I simply adding a sub, already have the Technic harness with the LOC he supplies. Will I get the full signal below the factory sub crossover point? If not, does say an Audiocontrol Lci2 correct this?



Thanks

[Billfitz]

I don't know if it's high passed but it is EQ'd, which amounts to more or less the same thing. Measured nearfield my under seat woofers peak at 60Hz with a curve that looks like band pass, with a low frequency roll off below 60Hz steeper than the acoustic roll off of the speaker alone would explain. The only way to get a full band width signal to a sub amp is to capture it before it's processed by the stock amp. I don't know if the Technic harness does that. I'm not interested in a separate sub, it's not worth the bother with the classic rock I listen to, so I've never investigated the Technic beyond what I've seen posted here. If it is taking the signal post processing then it would have to be compensated for in the sub amp if it has that capability, or by a separate EQ placed before the sub amp input.

[Johnny Chuttz]

Originally Posted by Billfitz

I don't know if it's high passed but it is EQ'd, which amounts to more or less the same thing. Measured nearfield my under seat woofers peak at 60Hz with a curve that looks like band pass, with a low frequency roll off below 60Hz steeper than the acoustic roll off of the speaker alone would explain. The only way to get a full band width signal to a sub amp is to capture it before it's processed by the stock amp. I don't know if the Technic harness does that. I'm not interested in a separate sub, it's not worth the bother with the classic rock I listen to, so I've never investigated the Technic beyond what I've seen posted here. If it is taking the signal post processing then it would have to be compensated for in the sub amp if it has that capability, or by a separate EQ placed before the sub amp input.

Thanks. My amp has a bass boost. I'll play with it once I get everything installed over Christmas.