[Technic]

Originally Posted by efunroom

Technic,

I saw some other types DSP processor in the forum, for example, AudioControl LC6/EQS/DQXS/DQL-8, JL Audio Cleansweep, Audison bit1 etc. What is difference among these devices? For E90 with HIFI option, which one is best fit ?

Thanks!

The only adjustable DSP processors in your list are the DQXS, the DQL-8i and the bit one. The Cleansweep is a non-adjustable DSP processor, the LC6i is an active line converter and the EQS is just an analog EQ.

"Best fit" depends on what you want, installation, your budget. You should download the owner's manuals on each manufacturer website first and learn for yourself the individual features and capabilities of these units before making any decision.

For example, the DQL-8i that I recommended before is easier to install than the DQXS (these devices are techical and feature-wise identical) just because of the wired inputs vs. RCA inputs respectively. However, the more efficient processor of these two for the HiFi is the DQXS, as its inputs are low level. What that means is that the HiFi OEM HU low level outputs can be used directly as inputs of the DQXS without any unnecessary high to low conversion as in the DQL-8. That conversion will attenuate you input signal so you will need to increase the gains in the DQL-8i more than what is considered "normal" to compensate for the low inputs levels. Depending of the installation and tuning this high gain adjustments could cause noise.

There is no such attenuation with the DQXS, actually the inputs will be increased in voltage immediately by raising the input gains as this is a line driver and not a line converter input section. So you will have a much better range of gain adjustments and output voltage in the DQXS and a better capability of reducing noise -if any. The downside is that you will need to solder RCA plugs into the OEM HU output wires to use the DQXS.

[efunroom]

I have a budget around $1500-2000 to upgrade my car. I searched the posts to try to understand the upgrade path since I am newbie in this area. Here is what I understand, pls correct me if I'm wrong.


<<My understanding>>
The full path of audio signal processing:
[Summing] -> [Normalization] -> [De-processing] -> [EQ] -> [Crossover] -> [Amplify]

[Summing]: take all of the input audio signal and merge them to a full range signal
[Normalization]: flating the input signal which means all the frequence of the signal has the same intensity(dB).
[De-Processing]: remove the EQ in the input signal
[EQ]: add new EQ to signal
[Crossover]: divide the signal by frequency
[Amplify]: change the input into a high level signal for driving the loudspeakers

The following table summrized the process way in each phase.

Summing..........Analog
Normalization....Analog
De-processing...Analog
EQ..................Analog or Digital
Crossover........Analog or Digital
Amplify............Analog


<<Question>>
1) For the E90 with HIFI configruation, the HU output signal is flat. so it can be used directly without "summing" and "Normalization", right?
2) For the EQ, The HU has the treble/bass setting, so "de-processing" is required. Is it still need if set these EQ setting off in HU?

<<configuration>>
Would you pls give your suggestion for my configuration. BTW, any comments about MACROM's speaker since there is a local dealer here. For the DSP, do u think Audison bit1 is the perfect one? since I saw it in your post at m3post.

Thanks a lot!

[VP Electricity]

Hi, welcome, happy to help.

Originally Posted by efunroom

<<Question>>
1) For the E90 with HIFI configruation, the HU output signal is flat. so it can be used directly without "summing" and "Normalization", right?

Correct.

Originally Posted by efunroom

<<Question>>

2) For the EQ, The HU has the treble/bass setting, so "de-processing" is required. Is it still need if set these EQ setting off in HU?

Not clear what you mean, We usually think of equalizers as adjustable. But the BMW amplifiers - all of them - have fixed equalization curves built in. Even if all tone controls are set to flat, the signal coming out of the amplifiers has been equalized to a specific response.


Your signal path list is mostly correct. The normalization and de-processing are the same thing, and should probably be called "de-equalization", since there is no other change occurring with any product I've tested.

The de-equalization can be analog or digital, but with most current products it is digital.

So I would state it this way (this is my understanding of signal flow for, say a 360.2 or an Audio Control DQL-8):

"Line Output Conversion" (attenuation of speaker-level signals, isolation of grounds, impedance matching) (analog)

Summing (analog)

Analog to digital conversion

De-EQ and EQ (digital)

crossover (digital)

time delay (digital)

output level (digital (I think))

digital to analog conversion

output to amplifiers (analog)


As you say, in the above signal chain, if you are using the analog flat, full-range outputs of the HU, you don't need a lot of that.

You don't need attenuation, you don't need summing, you don't need de-EQ.


I have not seen Macrom speakers in the US in a long time They used to have a good reputation, but there was some relationship with Morel here in the US in the past which I think is no longer in effect.

[efunroom]

VP Electricity, thanks for your post which help me a lot!

I am confused with low level and high level signal. Many DSP or AMP can accept both of them, but how to determine a signal is low level or high? Can I say line level is low level and speaker level is high level? differential signal is low and unbalanced signal is high?

Technic said "... the HiFi OEM HU low level outputs can be used directly as inputs of the DQXS without any unnecessary high to low conversion as in the DQL-8". So the output of HU is low level and DQXS also regards it as low level input, but DQL-8 regards it as high level? When high to low conversion is required? it is device dependant?

Next question is about the flat signal. Can I think that All frequence waves in the flat signal has the same amplitude? What is the benifit to use a flat signal as input?

Back to my configuration, I am thinking about the DSP with digital SPDIF input since I plan to install a carputer. Using a sound card with SPDIF output, the SQ may better. OEM HU will take charge of RADIO. PC will play mp3 and DVD audio. Both of them can play CD. (I am not sure if PC can adjust the volume)
.
OEM HU ----> DSP --> AMP(s) --> Speakers
PC ------>
.
Alpine has some such products. for example PXA-701, PXA-H900, PXI-H990. Audison also announce the bit one, but I can not find bit1 in Audison website (out of market?). Any experience or suggestion about such DSP?

[VP Electricity]

Originally Posted by efunroom

I am confused with low level and high level signal. Many DSP or AMP can accept both of them, but how to determine a signal is low level or high? Can I say line level is low level and speaker level is high level? differential signal is low and unbalanced signal is high?

It is most simply defined as a voltage level. Higher levels can drive speakers. Lower voltages are called "pre-amp" voltages as they are not amplified enough to drive speakers. (This is somewhat confusing with OEM systems, as several OE amps, such as the BMW pre-bangle cars such as the E36 and E46, took high-level signals into the amplifier and there was no true preamp signal. But in the aftermarket, the signal to the amp from the head unit is always a low-level preamp signal.)

I avoid the use of the term "line level" because it means different things to different people, especially in pro audio compared to car. I always used it to describe low-voltage preamp signals, but pro signals can be very different.

Originally Posted by efunroom

Technic said "... the HiFi OEM HU low level outputs can be used directly as inputs of the DQXS without any unnecessary high to low conversion as in the DQL-8". So the output of HU is low level and DQXS also regards it as low level input, but DQL-8 regards it as high level? When high to low conversion is required? it is device dependant?

You highlight a problem with many OE interface devices. It is difficult to make an input work with either a high-power speaker signal or with a low-voltage preamp signal. The initial Rockford 360.2 had problems here, as did the JL CleanSweep.

I am not too familiar with all the Audio Control products, but I think that technic is referring to the fact that some have RCA connectors and balanced circuitry on those inputs, and some have high-level LOC circuitry on bare wire inputs.

A true balanced input can accept low-voltage preamp signals, and it can accept medium-level speaker signals (such as from a deck or a small OE amp). It doesn't work as well with very high-power amplifier signals such as from bigger OE amplifiers. That's where the LOC inputs com in, such as in the LC6/7/8 and the DQL-8. The DQL-8 is essentially an LC8 and a DQXS in one box, with the signal going into the LC8, and the output of the LC8 going to the DQXS.

Originally Posted by efunroom

Next question is about the flat signal. Can I think that All frequence waves in the flat signal has the same amplitude? What is the benifit to use a flat signal as input?

Audio gear without any equalization or crossover filtering should amplify all signals equally - it should not emphasize some notes and attenuate other notes. The goal of good design of amps, speakers, etc., is to play all notes proportionally. This is almost impossible to achieve, but is the goal - and electronic components come far closer than speakers do.

A pink noise signal has equal energy at each octave.

Originally Posted by efunroom

Back to my configuration, I am thinking about the DSP with digital SPDIF input since I plan to install a carputer. Using a sound card with SPDIF output, the SQ may better. OEM HU will take charge of RADIO. PC will play mp3 and DVD audio. Both of them can play CD. (I am not sure if PC can adjust the volume)
.
OEM HU ----> DSP --> AMP(s) --> Speakers
PC ------>
.
Alpine has some such products. for example PXA-701, PXA-H900, PXI-H990. Audison also announce the bit one, but I can not find bit1 in Audison website (out of market?). Any experience or suggestion about such DSP?

Audison website is upgraded only every 3 years or so. Don't know if it is available in your market.

When working with SPDIF outputs, you will get much better sound quality than with most PC soundcards, but you will have a volume control problem. The control panel for the audison bitONE would solve that problem, I believe (again, Technic knows more about this product than I do, he has one and mine has not arrived yet). It sounds like you will want to do in-depth research on this question.

[efunroom]

I want to double confirm that the output signal of the E90 OEM HU (HIFI option) is balanced & low-level & pre-amp & flat. --- what voltage of the signal (Vrms)? --- It can be directly plugged to the low level input of audison bit one.

OEM HU--> Bit one --> PDX-5 --> MARCOM midrange 4" & tweeter 1" speaker, SWS 8"

I heard that Audison is developing a DRC plugin for PC, it sounds great. BTW, where can you buy the audison bit one? It is not available in my area(China). Not sure if it can be bought in Chicago since I have a friend living there.

[VP Electricity]

Feel free to test your own car , I've confirmed as much as I'm going to.

The problem for the bitONE might not be voltage. Audison RCA inputs on the amplifiers are common-ground inputs, I don't know if the bitONE inputs are as well. You cannot run balanced signals into common-ground inputs.

[strike4A]

Audison Bit One manual if anyone's interested.

My install is as follows:

OEM HU --> LC6i --> PDX-5 --> Focal KRS100 components, SWS-8x

Once the speakers have bedded in I will make the decision whether or not to add an EQ. No hiss on my system but gather that's not gospel for some repeating the above.

[efunroom]

Originally Posted by VP Electricity

Feel free to test your own car , I've confirmed as much as I'm going to.

The problem for the bitONE might not be voltage. Audison RCA inputs on the amplifiers are common-ground inputs, I don't know if the bitONE inputs are as well. You cannot run balanced signals into common-ground inputs.

VP, I just forgot this, thanks for your reminding. Need check if bit1 can accept differential/balanced signal since the manual dos not point it out clearly. If it can not accept the balanced signal, which is the better solution?

1) OEM HU --> OEM AMP --> Bit one --> aftermarket AMPs --> aftermarket speakers
2) OEM HU --> LOC (LC6 or LC6i ?) --> Bit one --> aftermarket AMPs --> Aftermarket speakers

Since the output signal of OEM HU is flatting, do I really need the DSP? or just need a aftermarket AMP which accept balanced signal as this

3) OEM HU --> aftermarket AMP --> aftermarket speakers

or this if the AMP can not accept balanced signal

4) OEM HU --> LOC --> aftermarket AMP --> aftermarket speakers

.

[efunroom]

Found a post at here

So far the bit one.1 can handle the HiFi OEM amp (the standard system in the M3 and 3-Series) and the Logic7 OEM amp (only 3-Series) outputs at the high level input section. The OEM amp in the HiFi can be completely removed and the OEM HU/iDrive outputs used as straight inputs into the low input section of the bit one using RCA plugs, no need of anything else.

Seems that bit one can accept differential input, need more search to confirm

EDIT: Got the Technic's confirm -- "Yes, it does accept differential inputs."

[efunroom]

Originally Posted by strike4A

Audison Bit One manual if anyone's interested.

My install is as follows:

OEM HU --> LC6i --> PDX-5 --> Focal KRS100 components, SWS-8x

Once the speakers have bedded in I will make the decision whether or not to add an EQ. No hiss on my system but gather that's not gospel for some repeating the above.

If you have the HIFI option, PDX-5 can accept balanced signal. Why need the LC6i?

[Technic]

Originally Posted by efunroom

If you have the HIFI option, PDX-5 can accept balanced signal. Why need the LC6i?

The LC6i could help in lowering noise (hiss) and in adjusting the output voltage of the OEM HU to better match the max input level of the PDX (OEM HU output level 5V max, PDX input level 4V max).

Technically, a Matrix line driver is more efficient than the LC6i line converter just because the OEM HU outputs are low level already, so they don't need to be converted/attenuated, just driven and adjusted.

[efunroom]

Originally Posted by Technic

The LC6i could help in lowering noise (hiss) and in adjusting the output voltage of the OEM HU to better match the max input level of the PDX (OEM HU output level 5V max, PDX input level 4V max).

Technically, a Matrix line driver is more efficient than the LC6i line converter just because the OEM HU outputs are low level already, so they don't need to be converted/attenuated, just driven and adjusted.

Got the point, thanks Technic!

Now come back to my planned config: Audison Bit one

1) Glad to know the OEM HU output is 5V. Does bit one accept such voltage as it's low level input?

2) I noticed that the volume/EQ will be auto-adjusted with speed. This is handled by HU or the AMP? Hope it is the AMP, then the output of the HU is a ideal signal.

3) Seems that bit one has some problem (noise) when using the digital input. I Just watch the progress. Hope audison fix it ASAP.

[efunroom]

Since the headunit(RAD2) with HIFI option has the MOST interface, can I use the mObridge DA1000 Preamp to get the digital output from that MOST interface? RAD2 need software upgrade?

[mObridge]

Originally Posted by efunroom

Since the headunit(RAD2) with HIFI option has the MOST interface, can I use the mObridge DA1000 Preamp to get the digital output from that MOST interface? RAD2 need software upgrade?

Yes you can use the DA1000 with the radio and no you do not need an upgrade. Plug 'n play my friend, plug 'n play

cheers,

mObridge

[efunroom]

Originally Posted by mObridge

Yes you can use the DA1000 with the radio and no you do not need an upgrade. Plug 'n play my friend, plug 'n play

cheers,

mObridge

I remember that some guy said the digial and analog signal can not coexist. Not sure if it is ture.

[VP Electricity]

Originally Posted by mObridge

Yes you can use the DA1000 with the radio and no you do not need an upgrade. Plug 'n play my friend, plug 'n play

cheers,

mObridge

Can he? Do you mean, it's shipping? Or did you mean "will be able to"?

If you're gonna talk capabilities, can you also update us on dates?

[mObridge]

Originally Posted by efunroom

I remember that some guy said the digial and analog signal can not coexist. Not sure if it is ture.

You do need to unplug the existing external amp MOST connection of course so only our unit does exist.

cheers,

mObridge

[mObridge]

Originally Posted by VP Electricity

Can he? Do you mean, it's shipping? Or did you mean "will be able to"?

If you're gonna talk capabilities, can you also update us on dates?

Select dealers do have them world wide for demo pieces and trialing and have had them for some time now. We've been somewhat a little busy though with production on other projects but production for this is commencing as we speak which will take us up to the end of September.

cheers,

mObridge

[VP Electricity]

Originally Posted by mObridge

You do need to unplug the existing external amp MOST connection of course so only our unit does exist.

cheers,

mObridge

But do we yet know if the BMW HU's analog outputs work at the same time as its MOST output?

[VP Electricity]

Originally Posted by mObridge

Select dealers do have them world wide for demo pieces and trialing and have had them for some time now. We've been somewhat a little busy though with production on other projects but production for this is commencing as we speak which will take us up to the end of September.

cheers,

mObridge

So did you just say "shipping to dealers end of September"? For BMW?

[VP Electricity]

Originally Posted by mObridge

You do need to unplug the existing external amp MOST connection of course so only our unit does exist.

cheers,

mObridge

Or was he asking if the device with analog and Toslink SPDIF outputs can have both outputs active simultaneously? (For bitone.1 use, this seems important...)