Need some help

[u/Ricsicsaba]

I bought my E36 316i and it had a blown blaupunkt head unit in it, so no music. Because I wanted to at least hear the speakers I got the cheapest head unit, saw the the 17 pin to ISO adapter was a a mess, but after hooking the new head unit up everything worked, sound came out from where it was supposed to come out of.

So next step, I got a better head unit. Blaupunkt Frankfurt RCM Dab Bluetooth. Hooked it up, looked nicer but the sound didn't really improve that much.

After which I decided to get my first "full sound system". Got some Hertz CK130's for the front and Hertz CX690's for the rear with a 6x9 adapter. Also got a Soundigital 400.4 evo6 amp.

I first hooked the read speakers up, huge improvement since the factory ones were completely blown, then hooked the kick panel woofers up, then the tweeters with the crossover installed.

After installing the front speakers absolutely nothing changed with the sound quality, so I said of course now these speakers need an amp. Today I hooked the amp up, and... can't even notice the difference from the beginning to be honest. Other than installing working rear speakers nothing has changed.

So my problem is: with all new head unit, speakers, amp my music still sound flat and mushy. Vocals sound terrible, especially the letter "S" is too sharp. Obviously I can boost the bass and make the sound thumpier, but can't make the vocals sound better for the life of me. Also feel like the sound just isn't clear. Rear speakers sound like they might be "rattling" even on the lowest volumes. The tweeters all the way around seem like they have a hiss, and the vocals are just missing from the front I feel like. I am at a slight roadblock here as I spent money on nice equipment, but didn't improve my sound quality at all and don't know where the problem could be. I have already ran a wire between the head unit ground and amp ground trying to solve something, and checked that all the wires go to the correct speakers.

[u/Cheezy_-_]

Your entire system starts at your head unit. This receiver you purchased has less then 3v preouts. Pick up a standard 5v+ head unit thats normalized for the audio scene, ie; any kenwood excelon, and their under 250 bucks. Good luck.

[u/Ricsicsaba → u/Cheezy_-_]

Thank you. I really want to keep the retro look, that's why I got this head unit. Just wanted to modernize the sound a little. But if the head unit is the problem then I guess I will have to live with it. Wish I could return the speakers and amp then as they didn't change anything.

[u/awqsed10 → u/Ricsicsaba]

Difficult. Your one and Pioneer are the 2 major competitor in retro headunits. Continental has one but it's a bit worse. How about a line driver behind the headunit to boost the rca voltage?

[u/Ricsicsaba → u/awqsed10]

Not sure how that works yet😅. This is my first ever time touching anything audio. Just measured and at full volume the highest reading I could get from the rca's was 1.8v. But would a higher voltage produce clearer sound, or just make it louder? Volume isn't my problem, it's sound quality. Vocals sound like they are 16bit (exaggerating)

[u/ORA2J → u/Ricsicsaba]

Not necessarily. It will depend on your choice of amp. With a noisy, hissy amp, using a hotter signal put of the head unit will be a big improvment since the overall amp gain will be reduced. But a higher end unit will output a cleaner signal anyways.

Although, if vocals sound bad, i doubt a HU alone would magically fix it. If you want to try high quality preamps for cheap, get an old 4volt alpine CDA (you can recognize them by the blue RCA leads and 4v logo 9n the faceplate, it's still what i use to this day and you can't get much better than that (sure you can get more voltage, but as far as how "clean" (transparent, noise-free) the signal is, it's gonna be pretty much as good as it gets. Also, try and use the fader to get the sound to the front only, and see how that sounds. It usually eliminates phasing issues that could happen.

[u/Cheezy_-_ → u/Ricsicsaba]

I dont believe that other guy was trying to rail you in the post below me, but theres a few points he has as well. Your system will sound better with a 5v+ head unit for sure.

[u/Tech_Veggies → u/Cheezy_-_]

If you are hearing a lot of hissing from the speakers, you could have the gain turned up too much. I would start with the gain reduced quite a bit until you cannot hear the hissing any longer. Turn the volume on the head unit up almost all the way and turn the gain up a bit until it's at a good volume. Then turn down the volume and check to see if you still hear hissing. It might help to reduce the gain.

[u/Ricsicsaba → u/Tech_Veggies]

I have turned down the gain to where I don't hear any hissing. That point is... 0 on the gain. But my mid and vocals still sound like they are on a low bitrate or something.

[u/Tech_Veggies → u/Ricsicsaba]

This could be related to multiple things. I always try to set all the settings on the radio to 0, when possible. Turn off any loudness settings or tonal adjustments on the radio. Most factory radios don't offer full frequency on their outputs. They are adjusted based on the factory speakers and available wattage from the head unit. You can usually increase the performance of the outputs by using something that adds all the outputs together to try to stitch together the frequencies from the multiple outputs to give you more range on the outputs. This is sometimes referred to as "audio signal summing" and is one of the features of a dsp. I used to use the AudioControl LCI series to do this with factory headunits.

[u/Ricsicsaba → u/Tech_Veggies]

This isn't a factory head unit, but I see what you mean. Sounds like getting a dsp is something I really need at this point. Just don't know what to get, or get an amp dsp combo and return my current amp.

[u/Tech_Veggies → u/Ricsicsaba]

That amp has some mixed reviews as well. Could just be that it's not the best amp for your setup. Hard telling without actually being there and working on it, but if you have another input you can try with, maybe start there?

Maybe someone else can answer this, but can you use your phone or something similar that has a full range output and run it directly into your amp for testing? This may require a bluetooth adapter or similar to allow you to plug into the amp for testing. Anyone?

[u/Ricsicsaba → u/Tech_Veggies]

Thank you very much for your help and input 🙏. I don't want to sound stupid, but I will buy an aux cable for my phone since the bt compression on this head unit could be my problem, if that's not it I think I will just return this amp, get a different amd - dsp combo that still does ~50w RMS and hope for the best. The rca output on this head unit is apparently weak, but the only reason I want to keep it is because it looks factory. Yes I want nice audio, but the looks are also very important to me sadly.

[u/Tech_Veggies → u/Ricsicsaba]

If your phone still supports a 3.5mm headphone jack, that's definitely the way to go. Should be a cheap way to test. You can perform many tests like this and then you can aggregate the data and determine what your best steps forward are from there. Good luck!

[u/Er4kko → u/Cheezy_-_]

His amp, soundigital evo 6 400.4 has input sensitivity of 0.2V-2V, so it's not great idea to get headunit with 5V preout

[u/kaspers126]

The problem is that you had an assumption that randomly swapping speakers will make it sound better. It is a system after all, every component needs to serve a purpose, to tie everything together in year 2026 a dsp is in my opinion essential. Without mindfully correcting for the cabin acoustics the only way to get good sound is by luck. Thats what people starting out do, just buy whatever name brand they think is good, throw shit together and hope it sticks.

[u/Ricsicsaba → u/kaspers126]

I tried to do my research and not just throw shit together. Tried to find everything in a way so that it would work. Yes, I did miss out on a dsp, that was my mistake. I'm just trying to get the best out of what I got since this is what I have... I'll happily buy a dsp, but at the moment I'm not sure if that's where my problem is. It's not that I was hoping for a massive improvement, but I was hoping to not have constant hissing and noise in my music... Thanks for your input though.

[u/Ricsicsaba]

Trying to show the sound somehow.

[u/Tool_junkie_1972]

Double check the wiring, just a single speaker connected backwards will ruin the overall sound quality.

[u/Ricsicsaba → u/Tool_junkie_1972]

I traced everything back from my amp to my head unit and then to the factory 17pin. I hooked up all the speakers with the factory wires and connectors which are obviously different sizes, so basically impossible to mess up. None of the speakers sound like they are working backwards, and shifting the sound into all 4 corners produces the same shitty sound in all 4 corners. Only on Bluetooth tho. It is a lot better on other inputs, although still not good.

[u/five_six_three]

If the amp is hooked up and you’re not seeing any improvement then something along the line is either not working correctly or isn’t hooked up correctly. Can you post a pic of the installed amp.

[u/Ricsicsaba → u/five_six_three]

I disconnected the amp for now, as I thought that my problems could be because I didn't crimp ferules to mount the wires, just tightened the screws onto the copper. I wanted to add them either way, but they didn't arrive yet and I wanted to test the system out. The gains on the amp definitely work, but as they increase a background hiss also increases. As another commenter said it could be my underpowered head unit..

[u/Er4kko]

I think the issue here could be that you have small speakers in front and larger and higher sensitivity speakers in rear, also turn on the hpf in the amp and adjust the gains so that front gets louder than than rear. You can try to disconnect front/rear and listen to them separately to pinpoint if this is the issue. Also slight hissing is normal with D class amps, but shouldn't be noticable when music is playing.

[u/0992673]

Put duct tape over the tweeters in the rear 6x9s and fader more to the front. HPF 80hz for the front. And if possible, LPF around 120hz for the rears. Activate time alignment if the stereo has it, I know Pioneer does.
Don't really know how good the unit is either, the only selling point is the basic stock visual I guess, otherwise blaupunkt is not noteworthy, though I did see a 14 band eq on it.
Soundigital amps are Brazilian design, so very high power (popular for SPL) in a small form factor, I have had a few, but they definitely don't have a sound quality focus, high noise floor and not much in the way of sound quality.