More details for KEF Audio

[FederGigant]

The split configurations that you are familiar with in other cars are that way solely for packaging reasons, not because it's the "right" way to do things sonically. Most audio engineers consider car audio a terrible abuse of engineering for this, and many other reasons.

The KEF approach is better, though certainly not ideal due to the obvious limitations of a vehicle cabin.


To be fair, the only KEF components used in the Emira system are the Uni-Q drivers themselves. It's not their head unit, not their DSP, not their amps, and not their subwoofer. We also don't know who did the integration or tuning of the system, it may have been folks at Lotus or even Geely, rather than KEF. Lots of unanswered questions and very little info.

I suspect that some adjustment may be possible directly on the DSP amp unit if someone with the appropriate skills gets their hands on one.

If the system is not to my taste, I will try to rip the car apart to reach the dsp and see if I can connect it to a laptop, do some measuring and try to get better results. It should sit somewhere behind the luggage compartment behind the seats, probably just covered with some loose carpet.

 

[Mctaff]

FYI, just so you know how arbitrary this stuff is... for years I thought the Harman Kardon system in my BMW was mediocre at best. Muddy mid-bass, harsh tweeters, not great overall.

Then 2 things happened. First, some enterprising audio engineer on the BMW forums used an RTA analyzer in his car to figure out the best EQ settings to fix the nonlinearity of the frequency response, and they ended up being really non-intuitive settings with wild swings of the EQ bands. Huge improvement though, that fixed the muddy mid-bass and tightened everything up.

Then I got an external DAC (Helm Audio Bolt) that I connected to my phone with USB-C, rather than using the Bluetooth connection. Input then went through the analog AUX in on the car. The change there easily DOUBLED the power of the system, enormous increase in power all across the frequency band with zero additional distortion. HUGE bass that you can feel in the seat of your pants from the underseat woofers, super clear and present midrange, and no additional harshness on the top end. Unbelievable change.

The difference, ultimately, was about the signal level upstream from the amp. I thought it was an all-digital signal chain on the BMWs (this is a 2014 with NBT and HK) but the proof is in the result. Enough for people to immediately remark on it who have spent substantial time in my vehicle over the years.


All this is to say that there are lots of compromises in any car audio system. Figuring out what they are is a matter of being willing to mess with it, take it apart a bit, and figure out what the missing link may be. In most cases, it's a few settings.

You’ve always got a dac in the chain… it just might be a really poor one.

I bought a £400 chord external dac and it was no better than the one in my iPhone so it went straight back!

 

[Porter]

If the system is not to my taste, I will try to rip the car apart to reach the dsp and see if I can connect it to a laptop, do some measuring and try to get better results. It should sit somewhere behind the luggage compartment behind the seats, probably just covered with some loose carpet.

Excellent. From what I've read, it seems to be a Harman unit conceptually similar to this one or this one, coupled with another amp from Geely that they used in the Lynk & Co 01. Good luck with it, and keep us posted.

FYI there is DSP tuning software downloadable from each of those links.

 

[Porter]

You’ve always got a dac in the chain… it just might be a really poor one.

I bought a 400 chord external dac and it was no better than the one in my iPhone so it went straight back!

Yep - in this case the big difference wasn't the performance of the DAC, but the voltage level of the signal. Crazy how much of a difference it made.

 

[Cachaco131]

Some serious geeking out here. My F80 has a HK system but the lack of insulation makes the radio rather useless. I just turn the volume up.

 

[Nova]

Yep - in this case the big difference wasn't the performance of the DAC, but the voltage level of the signal. Crazy how much of a difference it made.

Depending on the architecture of the system... older designs may not have had an all-digital signal path. It was likely much easier to integrate a Bluetooth audio module and take the analog output from that to be fed into the audio amplification section. In those cases, poorly chosen coupling capacitor values would have attenuated the high and low frequencies, in addition to any output signal level issues that may exist. It isn't really until more modern multi-input SoC became commonplace that all digital audio systems became more popular in mass production consumer electronics designs.

For the Lotus Emira, Geely's system incorporates a Snapdragon 820 SOC and the data path from the Bluetooth module is PCM over an I2S bus. The 820 sends audio over a TDM bus to a NXP Audio/Radio-Tuner chip, and the NXP chip sends the audio over TDM to a A2B audio transceiver, which then sends it to the amp. Up to this point this is an all-digital audio path. It's not clear to me where the DSP magic happens, whether it's in the NXP chip or the audio amplifier.

Based on some additional research, Yamaha seemed to be providing an 8-Channel A2B based amplifier and speaker system solution to Geely with built-in DSP capabilities. I'm not sure if this is the one used in the Emira. The system shown includes 12 drivers: one sub, four woofers, three midranges, and four tweeters. It's likely that the four tweeters are on a passive crossover and shares an output channel with the four woofers. The midranges may have been added to fill in the midrange for the tweeter-woofer crossover region, where location-dependent cancellations are the most likely to occur and are impossible to correct even with DSP due to changing phase angle of the drivers. This may be the same crossover topology used by the KEF drivers in the Emira, though no need for corrective midranges since the Uni-Q driver is inherently time-aligned. But if the Uni-Q drivers are using passive crossovers, then the three plus two woofers plus two subwoofer drivers is only 7 channels...

What's odd is that the amp provided by Yamaha is spec'd at 385 watts, but that's when paired with Yamaha's speakers. It's possible that the KEF drivers' impedance necessitate a different amplifier, which is where the Harman "booster" amp comes in.

I don't know, I guess we'll find out more once someone gets a list of the parts in an Emira and we can dig for more info with part numbers.

EDIT: I just found out that the system in the Lynk & Co 01 is made by Infinity(Harman), not Yamaha. So never mind about all of the Yamaha stuff above.

 

[Eagle7]

Depending on the architecture of the system... older designs may not have had an all-digital signal path. It was likely much easier to integrate a Bluetooth audio module and take the analog output from that to be fed into the audio amplification section. In those cases, poorly chosen coupling capacitor values would have attenuated the high and low frequencies, in addition to any output signal level issues that may exist. It isn't really until more modern multi-input SoC became commonplace that all digital audio systems became more popular in mass production consumer electronics designs.

For the Lotus Emira, Geely's system incorporates a Snapdragon 820 SOC and the data path from the Bluetooth module is PCM over an I2S bus. The 820 sends audio over a TDM bus to a NXP Audio/Radio-Tuner chip, and the NXP chip sends the audio over TDM to a A2B audio transceiver, which then sends it to the amp. Up to this point this is an all-digital audio path. It's not clear to me where the DSP magic happens, whether it's in the NXP chip or the audio amplifier.

Based on some additional research, Yamaha seemed to be providing an 8-Channel A2B based amplifier and speaker system solution to Geely with built-in DSP capabilities. I'm not sure if this is the one used in the Emira. The system shown includes 12 drivers: one sub, four woofers, three midranges, and four tweeters. It's likely that the four tweeters are on a passive crossover and shares an output channel with the four woofers. The midranges may have been added to fill in the midrange for the tweeter-woofer crossover region, where location-dependent cancellations are the most likely to occur and are impossible to correct even with DSP due to changing phase angle of the drivers. This may be the same crossover topology used by the KEF drivers in the Emira, though no need for corrective midranges since the Uni-Q driver is inherently time-aligned. But if the Uni-Q drivers are using passive crossovers, then the three plus two woofers plus two subwoofer drivers is only 7 channels...

What's odd is that the amp provided by Yamaha is spec'd at 385 watts, but that's when paired with Yamaha's speakers. It's possible that the KEF drivers' impedance necessitate a different amplifier, which is where the Harman "booster" amp comes in.

I don't know, I guess we'll find out more once someone gets a list of the parts in an Emira and we can dig for more info with part numbers.

EDIT: I just found out that the system in the Lynk & Co 01 is made by Infinity(Harman), not Yamaha. So never mind about all of the Yamaha stuff above.

Lol okay. It was still fun to read though.

 

[Porter]

EDIT: I just found out that the system in the Lynk & Co 01 is made by Infinity(Harman), not Yamaha. So never mind about all of the Yamaha stuff above.

Yep I believe it's a variation on this theme: https://www.jbl.com/DSPAMPLIFIERDSP4086.html

 

[Nova]

Yep I believe it's a variation on this theme: https://www.jbl.com/DSPAMPLIFIERDSP4086.html

The amplifier uses an A2B interface, instead of analog inputs. Here's actually a series of videos produced by a hobbyist in China who hacked into the Lynk & Co 01 Harman amp:

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Edit: The chips used in this amp is the NXP TDF8546, which produces 20 Watts into 4 ohms with 14.4V supply at 0.5% THD. There are 8 total channels. This explains the need for a "booster".

Edit edit: The DSP is an Analog Devices SigmaDSP ADAU1466. I've used other SigmaDSP devices before, but not this particular one, these are pretty powerful given their relative low cost.

Edit edit edit: My initial reaction after taking all of this in, is that this Frankenstein of a system may not have a true owner. If it was a Harman branded system, they would have some need to do a proper system tuning because it's their name on the speaker grills. But since it's a KEF system, I don't know where the responsibility lies in tuning the DSP. *SOMEONE* needed to install a multi-mic array into a production vehicle to do measurements and use a development took kit to adjust the DSP parameters. Would KEF engineers have done this or Harman, or was it a tag team? I don't know, but I'm concerned that no one really owns this.

 

[Porter]

Edit edit edit: My initial reaction after taking all of this in, is that this Frankenstein of a system may not have a true owner. If it was a Harman branded system, they would have some need to do a proper system tuning because it's their name on the speaker grills. But since it's a KEF system, I don't know where the responsibility lies in tuning the DSP. *SOMEONE* needed to install a multi-mic array into a production vehicle to do measurements and use a development took kit to adjust the DSP parameters. Would KEF engineers have done this or Harman, or was it a tag team? I don't know, but I'm concerned that no one really owns this.

This is my growing impression as well. It might even be a Lotus or Geely team connected with the vehicle interior, combining elements from different suppliers. I'm interested to see what you discover once you get your hands on one.

 

[dgrace]

The amplifier uses…

Highest signal/noise post on this thread. Great stuff!

 

[Jonhklee]

Sounds like its making “business sense” to keep Geely sound chips, with KEF speakers only……. It’s even possible basic audio will be similar to premium system, bar KEF speakers and lovely brushed steel KEF Grill

Basic audio = add lightness
KEF audio = looks nicer

 

[Leonard]

Sounds like it making “business sense” to keep Geely sound chips, with KEF speakers only……. It’s even possible basic audio will be similar to premium system, bar KEF speakers and lovely brushed steel KEF Grill

Basic audio = add lightness
KEF audio = looks nicer

Unfortunately I think u could be right

 

[Jonhklee]

You know what. Did not expect a miracle for £60k, so base is increasingly getting my vote. It WILL be the true sweet spot, but will it stay at £60k, nobody knows. I hope they honour those of us who have waited and waited.

 

[Mctaff]

just test drove the car.

Kef is ok. Clearer with better definition than the bose in my macan. Defintely less bass, but more definition in the bass - the Bose has bass but its all muddled together into some deep vibrations, the Kef keeps the different sounds distinguishable, but has no thump in the stomach.

Could probably do with a little more volume if you like it loud, but was ok for me.

Soundstage could be better certainly.

Beforehand I drove the Vantage, with the Aston premium audio, which was an overall better system.

 

[Leonard]

just test drove the car.

Kef is ok. Clearer with better definition than the bose in my macan. Defintely less bass, but more definition in the bass - the Bose has bass but its all muddled together into some deep vibrations, the Kef keeps the different sounds distinguishable, but has no thump in the stomach.

Could probably do with a little more volume if you like it loud, but was ok for me.

Soundstage could be better certainly.

Beforehand I drove the Vantage, with the Aston premium audio, which was an overall better system.

Assume that was with Spotify or similar? Plugged in or Bluetooth?

 

[Mctaff]

Assume that was with Spotify or similar? Plugged in or Bluetooth?

Tidal Hifi (ie CD) quality over carplay/bluetooth

 

[Tonyshepp]

I’ve managed to identify that the standard setup isn’t powerful to drive the bass. If you iSolate the Bass, I used the equaliser on Amazon Music streaming and could get the powerful thumping bass and the volume I needed. It is definitely picky on the source quality of music but you do need to use the phones equaliser on your playback app to bring the best out of the KEF. I’m now happy it’s a good system… phew

 

[Eagle7]

I find it odd that when I first inquired to KEF about the Emira, the sales guy responded to me the next day. That's been over two weeks ago now, and I even sent a second email, and.... nothing. No other responses from him or anyone else at KEF. Very strange.

I'm going to try one more time, then consider calling to see if I can get someone on the phone. However, if the only part of the KEF system is their speakers, that might be why they aren't saying anything.

 

[CDM1855]

I find it odd that when I first inquired to KEF about the Emira, the sales guy responded to me the next day. That's been over two weeks ago now, and I even sent a second email, and.... nothing. No other responses from him or anyone else at KEF. Very strange.

I'm going to try one more time, then consider calling to see if I can get someone on the phone. However, if the only part of the KEF system is their speakers, that might be why they aren't saying anything.

Could be that KEF UK are not the ones calling the shots

Kef is owned by a Hong Kong company called GP acoustics. .

Could be that it was a deal done through China, more than the UK