[mxh]

Originally Posted by navin

If you are using an OEM HU with external amplifiers and speakers, you first have to "de-equalize" (that's not a real word but you get the drift) the OEM HU's output using a DSP (Audison, Alpine, etc. all make DSPs for this purpose) and then use the output from the DSP to drive the amplifiers and speakers.

How about if we just upgrade speakers and don't touch the OEM unit or amplifier. Would that be worth doing or would the difference be too little?
So what you are essentially suggesting is that the best practice is to replace both the OEM HU and speakers right? What about the steering audio buttons. I too have a 2015 City but I don't find the OEM HU to be that bad. The HU in Hyundai i10 though, that is real garbage.

[sidpunjabi]

Originally Posted by mxh

How about if we just upgrade speakers and don't touch the OEM unit or amplifier. Would that be worth doing or would the difference be too little?
So what you are essentially suggesting is that the best practice is to replace both the OEM HU and speakers right? What about the steering audio buttons. I too have a 2015 City but I don't find the OEM HU to be that bad. The HU in Hyundai i10 though, that is real garbage.

Hey mxh,

Essentially, changing the OEM HU is a pain for the customer and the installer, since it acts more like an Infotainment centre in today's cars - giving vital car stats in addition to being a music player.

I recently upgraded my ICE through a fellow bhp-ian and he told me the same thing that navin just mentioned.

Basically, the OEM factory fitted HUs come with a built-in equalizer which sends out audio signals at certain frequencies. The OEM speakers are configured to match this output.

If you change the speakers, there's a good chance that the new speakers will not match the audio configuration of the pre-set HU.

The resultant audio output varies from average to below average.

Since the HU configuration cannot be changed, installers attach an intermediary device called a DSP.

This DSP device works in 2 parts.

The input part receives the pre-configured audio signals from the HU and neutralizes it.
The output part is customizable by the installer. Here, the installer custom tunes the neutralized audio signals to match your new setup. These audio signals are then sent to your speaker, thus giving you maximum bang for your buck (literally).

PS: This is an extremely simplified, layman explanation and is based on my understanding of the process. I'll let the audio gurus handle the additional technicalities of it.

[navin]

Originally Posted by sidpunjabi

PS: This is an extremely simplified, layman explanation and is based on my understanding of the process. I'll let the audio gurus handle the additional technicalities of it.

This is a beautifully well written post. Thank you for this.

I am on a mobile so will post a more detailed answer tomorrow when I get to a laptop.

[mxh]

Originally Posted by sidpunjabi

Hey mxh,

Essentially, changing the OEM HU is a pain for the customer and the installer, since it acts more like an Infotainment centre in today's cars - giving vital car stats in addition to being a music player.

I recently upgraded my ICE through a fellow bhp-ian and he told me the same thing that navin just mentioned.

Basically, the OEM factory fitted HUs come with a built-in equalizer which sends out audio signals at certain frequencies. The OEM speakers are configured to match this output.

If you change the speakers, there's a good chance that the new speakers will not match the audio configuration of the pre-set HU.

The resultant audio output varies from average to below average.

Since the HU configuration cannot be changed, installers attach an intermediary device called a DSP.

This DSP device works in 2 parts.

The input part receives the pre-configured audio signals from the HU and neutralizes it.
The output part is customizable by the installer. Here, the installer custom tunes the neutralized audio signals to match your new setup. These audio signals are then sent to your speaker, thus giving you maximum bang for your buck (literally).

PS: This is an extremely simplified, layman explanation and is based on my understanding of the process. I'll let the audio gurus handle the additional technicalities of it.

Thank your for the informative post. In my case the OEM unit is not a super advanced one since I have the S-model of the Honda City. The steering has only one left side 5 way button, whose function is to adjust volume, seek radio station/ track, and select the Source. I am wondering if it's worth just changing the head unit rather than spending separately on a DSP. BTW once the HU has already done its stunts I don't see how this signal can be "neutralized". It's basically guesswork being done by DSP / tuner since the original signal isn't known and the resultant audio would be something which is processed twice by different DACs (OEM HU, DSP).

If the steering mounted buttons can be mapped easily to the new HU, I wouldn't mind changing it rather than paying for a DSP. Basically I need a unit with excellent sound quality and Bluetooth pairing. I do not need a touch screen or GPS. Also, would an amplifier required or can it be omitted? I'm not interested in a subwoofer. Just 4/6 speakers with audio that is faithful to the source with best clarity. I listen to all sorts of media from audio books to online radio (I don't use local FM/AM or CDs).

[sidpunjabi]

Originally Posted by mxh

Basically I need a unit with excellent sound quality and Bluetooth pairing. I do not need a touch screen or GPS.

mxh, I would be lying if I said I wasn't in the exact same boat as you about 2 months ago. So, I do understand what you're trying to say.

Also, I wish to clarify that when I said Infotainment, I meant it in a very broad sense. As in, OEM HUs are no longer standalone decks and 2/4 speakers. They are connected to other parts of the car as well - including steering mounted controls.

Originally Posted by mxh

I am wondering if it's worth just changing the head unit rather than spending separately on a DSP.

So, yes - if you wish to change the HU - you definitely can.

The reason I personally wouldn't recommend changing the HU is because:

- You may have to do a lot of trial and error to find the correct HU that not only accepts steering wheel controls but actually executes the assigned task.
It's pretty common to hear people say that their new HUs aren't responding correctly to the steering mounted controls. For example, the HU may change tracks when one presses the Volume button. In some cases, many claim that they find that the buttons go dead / unresponsive due to incorrect mapping.

Originally Posted by mxh

If the steering mounted buttons can be mapped easily to the new HU.

You hit the nail on the head with this statement. This "If" is a huge problem when upgrading the ICE with steering mounted controls.


- Let's assume you manage to overcome Troubling task number 1 of finding the perfect HU. You also have to consider its size and the whole fitment process. While the modification is relatively easy at any good installer, it'll eat away into your budget.

- There's also the marriage of the new HU with the new speakers. Just like your current HU, the new HU will also have its preset audio signals being sent to the speaker. Does the speaker receive it correctly? Is the output good enough? Can the new HU be configured to ensure that you get max bang for your buck?

- And finally, the cost - both in terms of time and money. The Pioneer DSP would cost you about 12-13k (including installation) while keeping the stock HU and controls perfectly intact. It'll also cost you less time to procure 1 since it's easily available. The cost of putting in a new HU while retaining all the controls, will be quite time consuming on the other hand. Whether it saves cash or not - is a different thing.

Originally Posted by mxh

Also, would an amplifier required or can it be omitted? I'm not interested in a subwoofer. Just 4/6 speakers with audio that is faithful to the source with best clarity. I listen to all sorts of media from audio books to online radio (I don't use local FM/AM or CDs).

Like I mentioned, I'm in the same boat here. In my opinion, an amp is really not necessary per se. Some do install it if they find that the current output is not loud enough.

In my opinion, I would classify that as a Level 2 installation and something that can be added later - if you feel the need for it.

I installed a pair of 6" components in the front, and co-ax in the rear along with the DSP. The sound is excellent as is. I have neither installed an amp nor a sub and I really don't find the need for it.

Originally Posted by mxh

BTW once the HU has already done its stunts I don't see how this signal can be "neutralized". It's basically guesswork being done by DSP / tuner since the original signal isn't known and the resultant audio would be something which is processed twice by different DACs (OEM HU, DSP).

I'll leave this to the audio gurus. They'll probably be able to explain this better.

Originally Posted by navin

This is a beautifully well written post. Thank you for this.

Thank you @navin.

[navin]

Originally Posted by mxh

BTW once the HU has already done its stunts I don't see how this signal can be "neutralized". It's basically guesswork being done by DSP / tuner since the original signal isn't known and the resultant audio would be something which is processed twice by different DACs (OEM HU, DSP).

The DSPs normally come with microphones. For the sake of argument lets assume these microphones are flat and accurate.

So when you plug the OEM HU into the DSP and then the DSP in to amplifiers and speakers the first part of the process is to run some test tones. In the past these test tones were on a test CD (the Alpine 650 for example), later they were provided via USB.

The test tones played on the HU are then detected by the speakers and the DSP tries to calibrate it's built in EQ till it hears a relatively flat sound from the speakers. The more locations in the car you place this microphone the more data the DSP has to play with and you can even average out the EQ curves. The DSP I have permitted me to repeat the test as many as 6 times (6 different locations) and average out the curve.

So in reality the DSP is not undoing the EQ of the OEM HU but is applying an additional EQ on top of the EQ in the OEM HU to arrive at a signal it believes to be flat.

Personally I find the "flat" curve of most DSPs (at least the ones I have heard) to be "too flat". Let me explain. I am old school. My ears were raised on old tube/valve amplifiers of the past (popular in the 60s) so that is my mental memory of good sound. In most cases this sound is very good (at least according to my ears) and not fatiguing.

So I trick the DSPs. How you ask? Most good speakers have crossovers that have a +3db or -3db HF boost or cut built in. I will let the DSP do it's thing and then after the DSP has delivered a flat signal I will open the speaker and switch to crossover so it is -3db lower in the HF that the DSPs calibration. This is what I did with the Alpine 650.

The Audison Bit one allows me to modify the EQ of the DSP so I do not have to do open the speaker but just twiddle with the DSP and tune it by ear. I trust my ears. There are very few ears I trust as much as my own. And NO ear I trust MORE than my own.

I recommend that anyone serious about getting to "good sound" also learn to trust their own ears.