The Seemingly-Awful State of Car Amplifiers .... Does it even matter?

[EJ3]

Well, sure, but if the noise floor of your car's amplifier is enough to kill the mood I think the amplifier is the least of your worries.

Not a mood, a lifestyle.

 

[Keith_W]

It's not the SINAD you need to worry about. It's whether the amplifier delivers what it claims. 300W claimed should mean 300W output.

 

[john61ct]

What 3rd party testing is for!

Especially when they claim Wrms @ 8Ω

Amir please get that CA30 done ?

 

[Frank Dernie]

Heyo,

I feel like I have learned a lot about home audio equipment over the years, in large part thanks to sites like ASR and the kind folk here.

One area where I know very little, however, is the world of Car audio.

The basics make sense to me; it's just a home speaker setup that's shaped a little different, but trying to choose source gear seems much more difficult, because it all seems to be garbage.

I get that ASR has bigger priorities than car audio gear, so there's not a ton of reviews here, but so far, the absolute finest car amplifier Amir has ever tested, the SounDigital SD300.2D -- a limited-edition device made with rare gallium-nitride magic -- manages a SINAD of only 93. A rating that would basically be a fail compared to desktop amps. Same with its other specs; they're not great.

But... it seems no one minds? I mean, when I browse a site like Crutchfield, I see dozens of amplifiers with glowing 5-star reviews. And, at first glance, this makes some sense, because, after all, these are cars we're talking about. They aren't exactly pristine listening rooms -- and that's before you add in all the road noise and engine noise, so a part of me understands that pure transparency might not be that big of a deal for these components.

I tried posing this question to an LLM, in regards to the Fosi CA30, which actually seems to measure respectably, especially considering the price, and it responded interestingly:



Still, I'd love to hear more about what you guys think, and whether this stuff really matters that much for car audio. Given that so little testing exists for car amplifiers, how does anyone have confidence in their purchase? How do you even decide which amp to buy?

Thank you!

IME, which is admittedly old, it is not possible to get good quality audio in a car. I gave up after years trying.

The problem with the car environment is that the speakers are packaged usually to suit the interior styling rather than get the drivers, at least if tweeters and mid drivers aren't coax, in the right place relative to each other, and the listener/ speaker location relative to each other is inevitably unsuitable for stereo.

The background noise, even in a quiet car, is up in the 70dB range cruising so a noisy amp is masked but so is bass since the noise is higher at low frequencies, so a lot of bass boost is almost always used, which can make it impressive but not high fidelity.

Most subwoofers are little more than one note resonators.

DSP can hide some of the dire effects but it is basically lipstick on a pig.

There were 3 options in my car, standard, Bose DSP with more power and more speakers for around £1000 extra and a Burmester system for > £4k.

I demoed the standard against the Bose and found it loud enough for me (the biggest gain for the Bose was the claimed extra power) and it had an even frequency response and lowish colouration on speech. I would never consider spending >£4k on car audio and, for me, the Bose was slightly worse, though it could give a faux surround effect for a single listener.

 

[davmol]

RawCat is a good YouTube channel, he does some measurements. I've recently installed the Helix 206DSP along with a 204DIRECT and have been very impressed. No idea how it measures but it sounds great to me, and the DSP and other features are excellent for the price.

 

[EJ3]

IME, which is admittedly old, it is not possible to get good quality audio in a car. I gave up after years trying.

The problem with the car environment is that the speakers are packaged usually to suit the interior styling rather than get the drivers, at least if tweeters and mid drivers aren't coax, in the right place relative to each other, and the listener/ speaker location relative to each other is inevitably unsuitable for stereo.

The background noise, even in a quiet car, is up in the 70dB range cruising so a noisy amp is masked but so is bass since the noise is higher at low frequencies, so a lot of bass boost is almost always used, which can make it impressive but not high fidelity.

Most subwoofers are little more than one note resonators.

DSP can hide some of the dire effects but it is basically lipstick on a pig.

There were 3 options in my car, standard, Bose DSP with more power and more speakers for around £1000 extra and a Burmester system for > £4k.

I demoed the standard against the Bose and found it loud enough for me (the biggest gain for the Bose was the claimed extra power) and it had an even frequency response and lowish colouration on speech. I would never consider spending >£4k on car audio and, for me, the Bose was slightly worse, though it could give a faux surround effect for a single listener.

True enough (there are those of us that like the engine sound [and my wife doesn't like music, anyway]). My 2004 truck originally had a Bose system that was deemed inadequate by the original owner (who bought the truck new in 2004) but did nothing about it.
The second owner (a friend) bought it in 2008 from the first one. And toward the end of ownership: did get rid of the Bose head unit (which would play CD's for a Pioneer unit that has a 4" screen, can play CD's and DVD's, has Bluetooth and 4 channels.
I bought it from him in 2024 and replaced the Bose speakers with much better sounding (to my ears) speakers.
I remember the Bose system in these vehicles as sounding just OK.
There is 100% chance that the system as it is now sounds way better than it did when it was a Bose system.
Can it be evenly compared to a great home system? Not at all!
But, as far as car systems are concerned, I would rank it in the top 30%.
Ranking it based on home systems, it ranks in near the top of the bottom 40%.
And, for what it's use case is, that is good enough (at least for me).

 

[Matias]

@Quinton595 Well we did have some interesting reviews here in ASR:

Alpine PDX-V9 Review (car amplifier)

This is a review and detailed measurements of the Alpine PDX-V9 four channel amplifier plus subwoofer amp. It is on kind loan from a member and costs US $999. Despite having one more channel than PDX-F6, The V9 is in the same box: Let's see if it measures as well as the F6 did. Alpine PDX-V9...

www.audiosciencereview.com

Alpine PDX-F6 Review (4 channel Car Amplifier)

This is a review and detailed measurements of the Alpine PDX-F6 four channel car audio amplifier. It is on kind loan from a member. When new, it cost US $849 but is now discontinued. Not a fan of the plastic trim which are showing their age now. But otherwise, it is a nice looking unit. I...

www.audiosciencereview.com

SounDigital SD300.2D Review (Car Amplifier)

This is a review and detailed measurements of the SounDigital SD300.2D stereo car amplifier. It is on kind loan from a member. Apparently only 200 of these were built using GaN transistor technology. Not sure of the original cost ($1,300?). From outside, the SD300 looks plain and and budget...

www.audiosciencereview.com

JL Audio HD900/5 Review (Car Amplifier)

This is a review and detailed measurements of the JL Audio HD900/5 four channel amplifier plus subwoofer amp. It is on kind loan from a member and costs US $1,290 on Amazon. This is a hefty amplifier packed in a small and dense package: There are the usual filters and such, all of which I...

www.audiosciencereview.com

But I am super curious to see how this BRAX RX2 PRO (€4.000 EUR) measures, based on ESS ES9039Q2M + OPA1612 + Purifi Eigentakt. Should be excellent.

BRAX RX2 PRO | Audiotec Fischer

BRAX MATRIX ML28 PRO – 2-channel high-end amplifier | PURIFIs “EIGENTAKT” Class D | 2 x 300 Watts RMS at 4 Ω | 2 x 510 Watts RMS at 2 Ω | Bridged 1 x 930 Watts at 4 Ω

www.audiotec-fischer.de

 

[MAB]

It doesn't seem that bad, a quick check of the car amps Amir has reviewed to date:

Median SINAD is 78 dB, if SINAD is the primary concern.
The median of the distribution of speaker amps Amir has reviewed to date is also 78 dB. A mixed bag.

I agree there are no autosound amps with 120dB SINAD like the Topping LA90. That being said, the MiniDSP Harmony has noise performance and frequency response that would be fine in home, let alone a car, and has 12 channels of DSP, and can be bridged in a variety of ways similar to a commercial installation amp. It's certainly not awful!!!

Amir has also reviewed some nice audtosound DSP, and head units. It seems a mixed bag, but there are nice gear available. I have some old Soundstream, Nakamichi, and A/D/S autosound electronics. I should test it, I would be surprised if it was poor. The A/D/S drivers I have tested and they are great even after years of use in two different installations.

 

[xanalog]

My biggest gripe has been trying to find new head units for older cars that don't look like a 70's disco.

My 20 year old GM has the OEM pair of 6.5" coax, a 6.5" pair in the doors w/xo to a pair of tweeters on the dash, and two 6/5' powered mid/subs, on the rear deck.
I plan to replace the 2-DIN head-end unit, w/6CD changer and its built-in 4-channel amp, with the FOSI CA30 and a separate 2 channel for the subs.

But, I can't find a &*^% head-end unit that does not have any mobile connectivity (Apple/Android Play) or even BT or WiFi.
A GPS, AM/FM/HD, a few analog RCA Inputs and a USB-C DAC w/8channel EQ. is all that I really need for SXM and a HiDizs AP80ProMax music library.
I aim to start going to the local car audio installers but most sell those 'connected' units.

 

[Rickysa]

But, I can't find a &*^% head-end unit that does not have........

I like/maintain older cars (70's thru 80's) and have reached the point that I'm combining hobbies: car repair and electronics. I'm still climbing the learning curve of the latter, but I figure gathering the bits and pieces, soldering them together, and putting them in a single DIN box has gotta be possible ...with knobs.