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August 24, 2017

It's all about in-car audio

We cleaned the garage and got ready to dive into the science of making hi-fi sound systems for cars - armed to the teeth with more questions than we could possibly answer in a single episode.

Watch as our Senior Sound Tuner, Morten Hermansen, joins us on Ask the Expert to answer questions about everything from the sound stage we try to achieve in cars to time-alignment and noise dampening.

This episode's question

Watch the entire video above or skip directly to the question you find interesting by clicking the links below: 

We kick this episode of with a question from Jay about time-alignment: does it really matter and can the 'average' person tell the difference?

Next up is a question from our long list of suggestions on Facebook: can you make special sound tunings for the car?

Jeremy and Kyle wonder what kind of influence reflective surfaces have in a car. Here's Morten's answer.

"What kind of sound stage do you try to achieve?" ask Jason and Matt.

Moving on to the next question: "Why do manufacturers insist on making the woofers bigger than the sub?" is from Dave Sandercock via Facebook.

"Is it a good idea to add noise dampening?" asks John Aasen.

The second last question in this episode of Ask the Expert is: "What can I do to improve my car sound system without spending a fortune?"

Finally, Craig asks: "The more power you feed the speakers, the better they sound. Why is that?"

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Thank you!

We want to thank all of you who posted questions on our Facebook posts. We didn't have a chance to answer all of your questions, but we'll keep them in reserve - just in case.

Subscribe now: Ask The Expert on YouTube

If you have any more questions, please share them with us - and the rest of our community - on our Facebook pagein the comment section on YouTube or send us an E-Mail with your question.

All the best,
Morten and Christopher

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Transcript

Christopher:

Hello and welcome to ask the expert. My name is Cristopher and I am your host. As you have probably noticed we have changed scenery this time and we are in our garage. And to be down here we actually had to move out a lot of secrets, Morten. And I know that you are one of the only three or four people in Dynaudio with access to this room. Can you talk a little bit about that?

Morten Hermansen, Senior Sound Tuner:

It is because that we have worked now for 15 years very close together with the Volkswagen. And this area here… is actually red area that have been approved by the Volkswagen to be an area we can have and install prototypes for the Volkswagen. So sometimes they arrive here with very big trucks.  Closed down – everything is covered by big sheets – at night perhaps sometimes. And then it is brought in here and everything is closed down. When it is a red area, nobody is allowed to come in here except a very few of us that can tune the sound.

Christopher:

So I cannot get access down here.

Morten:

No. (Laughter)

Christopher:

Uhm… So obviously you have access and you have that for a reason. So I want to know a little bit about what is it that you do here in Dynaudio.

Morten:

What we actually do down here is that we take these – often prototypes and do some sound tuning. A lot of the work we have naturally make some drivers that we can put in the installation of a car. And then we have to make - optimise the programme for the amplifier that we do it down here by listening to music and using a lot of computers to actually program the amplifier.

Christopher:

And you have done that for a lot of years now…

Morten:

I have done that for nearly 15 years.

Christopher:

We have a lot of questions today Morten. Should we jump right into them?

Morten:

Lets do it!

Christopher:

Great!

Christopher:

Morten – Jay. He asks if time-alignment actually makes a difference and if it is audible for a regular person?

Morten:

Yeah. It is a good question and one of the things that we do together with the Volkswagen is – every driver in the car actually have its own amplifier - in all our cars. And that gives us – the sound tuner- the possibility to actually timeline everything in the car. And it does a huge, huge, huge impact of especially in the sound staging. The way you experience that the musician is in front of you on the dashboard so to say and not actually coming from the left side door or right side door.

Christopher:

So If I were to go into a car and try to figure out if  - can I actually hear this time-alignment. I should try to notice sound stage?

Morten:

Yeah. Yeah. Try to imagine where the signal is coming – where the signal is standing or the guitar is playing… And by changing the time-alignment that actually the time that the sound will achieve you sitting in your driver seat, can give you the impression that the music is in front of you. Time-alignment in the bass region is very very important because a lot of bass system has tendencies to boom in the trunk and that is quite annoying. So if you can time align the bass performance in the front without actually delaying the tweeters so much as the bass, then you can really make the all the staging good right in front of in the windscreen.

Christopher:

So Jay, get in the car and listen for the sound stage. And one thing you said here was that you could have the sound either to weight to the left or weight to the right, and it makes me think of some questions that we suggested because we asked what would you like to know and gave you a couple of suggestions and one of them were, can we make different tunings for the car?

Morten:

Yeah.

Christopher:

We can do that?

Morten:

Actually we do. In the Volkswagen we have a setting called Focus, and the Focus setting is actually changing the sound staging performance of the car. In some cars, especially for the Chinese market, we actually made the sound stage perfect for the guy who is actually sitting in the rear. So, that was kind of another way to make the time-alignment in the different way so the most important person, the guy who probably own the big car was sitting in the rear and should have the staging experienced from there. So there’s... Four different kind of settings in Volkswagen where you can make it good for everybody so it is like in the front for both drivers in the front row or you can optimize it to the driver-self like you can call it ego kind of setting…

Christopher:

So if I am driving alone, I really want to get the best…

Morten: Absolutely… Then you can wide stage and you can actually tune it a little bit to be wider and fill the whole windscreen.

Christopher: So we can and we do actually?

Morten:

It has the functionality, yes, in every Volkswagen we make.

Christopher: As Jeremy and Kyle pointed out, a car is obviously filled with reflective surfaces. You have glass all over the place, and… I tried to think, is there anything we can do about it, how do you work with an environment like that?

Morten:

It is quite an opposite environment to actually make sound and good sounding systems compared to your living room, because as you said, reflecting areas very close by your head and your ears, but we kind of as a human being solved that out in our brain. So our brain is actually helping us in that direction. What it looks for is actually to make some recognized voices or instruments or stuff like that so if you use a timing to actually point into the direction that the brain is going to look forward to listen to. Then you actually do not hear the reflecting areas so much.

Christopher: So the brain actually does a lot of work itself.

Morten:

Absolutely. It sorts out the reflection when you have some earlier sound coming to you from a special direction then you are actually tuning to listening to that instead of the reflection.

Christopher:

But I guess when, you know, a car is pretty, you know the car and you know this is how Volkswagen... They built it every single time opposed to a living room where you have no clue what it looks like. It must be an environment where you can better, do not get me wrong, but it is you know what you have to tune for.

Morten:

Yeah, exactly. I know the environment that we are trying to listen to our system in because they are sitting in the seats and that exactly so I can optimize actually to make the car have some focus points some sweet spots as we acoustics call it. And the sweet spots are already know where people will be sitting so I can actually kind of optimize how soon should every sound arrive to that position so you get the full impression of good staging and a nice sound…

Christopher:

So that is for time-alignment that we talked about earlier…

Morten:

Absolutely. Without it, it would not be possible to actually make it. Then they will sound like something was booming in the trunk and the doors playing too loud on the left side because you are sitting very close to it. So, the balance is very important and for that we use a multi-channel amplifiers and time-alignment.

Christopher:

Now you said multi-channel amplifiers because I know we talked about that in the article we wrote before this and you said something to me about it earlier that we use a 12-14-16 channel amplifiers so can we talk a little bit about what does that give us of an opportunity?

Morten:

Yes, The really big advantage of having multi-channel amplifier is the tweeter and the mid-range does not demand that much power compared to the bass. So, actually having a lot of amplifiers using the same kind of power supply can sort things a little bit out and if they have their own channel, even tweeter can get the right time-alignment compared to the mid-range. That is very important to actually to raise the staging up into the windscreen because without it, it would really not be possible.

Christopher:

Okay. So the chain actually goes that, if we did not have that multi-channel amplifier, we could not get the time-alignment right and the sweet spot you talked about would be difficult.

Morten:

Kind of fussy yes, exactly. When we can do it with tweeters sitting in the mirror triangle of the front door, and the mid-range sitting a little bit low, then you can time-align that to the bass performance then you can get everything in the brain actually to fit and you can listen to the music as you would in a normal living room.

Christopher:

Okay, perfect.

Morten:

It is quite good…

Christopher: Yeah… Perfect!

Christopher: The next question is, now we have combined it is from Jason and Matt. And Morten, they want to know what kind of sound stage that we try to achieve and that we prefer?

Morten:

Yeah, when we try to make the sound staging by tuning into channels, for all the drivers in the car, normally we have a setting that will optimize the sound performance and the staging for the driver‘s seat, and also for the co-driver who is sitting next to him. They are actually due to we have central-speaker in the car today we can make the stereo image is actually in the front of both at the same time. We have this focus setting that we can switch to in the menu of the head unit, where you can actually move the staging to fill the whole windscreen. So it will go more to the middle of the car and to the right so you actually have a very good staging. But, doing that will actually decrease the performance in the other seat. So we have the all setting, where it is actually in front of the driver and then you can go to Egoist mode and do it with the wide staging.

Christopher:

Okay, and when we have the really wide setting, would that mean that here the signal in the middle of the dashboard, so right above the head unit?

Morten:

Yeah, just beneath the rear mirror, it will actually turn a little bit to more to the middle of the car but what we focus most on is actually to make it wider. So the right side of the car, if you are on left-handside driving, will actually play a little louder and come a little sooner so you get the impression that the stage is wide.

Christopher: So you have a big, big band in front of you…

Morten:

Absolutely. You are in the first row at the concert.

Christopher:

But basically you actually do two different cut. We make two different options for people and they can actually choose which they prefer or…

Morten:

Actually four different options. So we have left side optimized, the right side optimized, and then optimized for the rear seat driver. So they actually get kind of a staging in the middle of the car, sitting in the rear.

Christopher:

So we actually do it for everyone in the car?

Morten:

Absolutely. It’s  about  what you prefer. You can actually use the way of centering of the staging you want. But all settings are for the best achievable for everyone in the car.

Christopher: Perfect.

Christopher:

Morten, we have a question from David and he has made an observation that in many cars you have latches, woofers in the doors and the smaller, sub-woofer in the back. So Is there any particular reason for that?

Morten:

No actually it is a very good observation, the building of the car is actually very important that it has quite large woofers in the front. In the middle in rear doors it does not really matter but last sub-woofer actually participate in the good over-all bass performance in the car. So it is very important that woofers in the front actually can make some pressure in the low frequency area so your expectation of the bass is actually coming from the front. If all the bass was in the rear it wound sound like something is booming in the trunk.

Christopher:

You said something about the woofers in the middle of the car. They aren’t important in this or…?

Morten:

No not really because they are kind of in a bad position. Compared to the cabinet they are actually in the middle of the cabinet and kind of not putting in a lot in the bass performance actually if you have big woofers in the front, and  a large sub-woofer in the rear, that would actually make the best bass performance.

Christopher:

And is that for you know when David is sitting in the car, he has a large woofer in the front place some low-end  and in the back - that gives a better perception of the full bass?

Morten:

Absolutely, Absolutely! And a better coverage of the whole cabinet in the low frequency area. It is very important that you are sitting inside the box, and that you have to take in mind when building a bass system, that you remove a lot of standing waves if you have two kind of...

Christopher:

Two kind of bass players in there?

Morten:

Yeah, in the cabinet so you actually – cancellations…  There are some cancellation of the standing waves to the car.

Christopher:  

Okay, and when you say the cabinet it is obviously

Morten:

It is inside the car, yeah!

Christopher:

We have to think of as being the car's shell as the cabinet.

Morten:

Yes. Absolutely, yes.

Christopher:

Okay, David has had another question, he has made another observation, it is, he sees that in a lot of cars there is a free air - bass, I think it is...

Morten:

In the head shelf?

Christopher:

Exactly. And he thinks that this tends to rattle a lot. Why do not you build an enclosure for them?

Morten:

In the... In our design in Volkswagen we have a - close to enclosure as the sub-woofer driver because placing a big woofer in the head-shelf is like, it is really problematic because it can rattle a lot. There is a lot of movement in the bass region. And you have to do a lot of stiffness and a lot of extra work to actually make the head-shelf woofer work properly. I have seen it working but normally it would be better to actually place it in the trunk in a closed enclosure.

Christopher:

And we do that?

Morten:

We do that yes.

Christopher:

Okay, but it can work?

Morten:

It can work, yes.

Christopher: Cool.

 

Christopher:

Morten, John. He thinks that we should add noise-dampening to the doors. Is that a good idea?

Morten:

Absolutely. It is very important when you make sound systems in cars to secure that the driver is placed in a good cabinet so to speak. Compared to your living room loudspeakers, a steady and solid cabinet are very important for the performance. In some cars, in the lower end of the price range, they are not doing it because they want to save weight and money and in the more expensive car, the high class car, the doors are very, very good damped. So it would be a good idea and it will benefit the sound performance so if I have my own car I'll actually put some extras in because it will improve the sound performance.

Christopher: When we go back to - you said that in higher price range cars the doors are good. Is that because they are stiffer or is that…?

Morten:

Yes, they are stiffer and the interior is perhaps leather and more thick and more nice to touch and the whole weight of the door is actually quite increased compared to the smaller cars.

Christopher:

Okay, so there is actually some noise dampening in high-quality cars?

Morten:

Absolutely, because the customers who are buying these kinds of cars will also prefer to drive on the high-way with a high speed and not have all the road noise, and stuff so they are actually quite more damped than the usual one.

Christopher:

Okay. And you just said, I've heard that if you had your own car, you would add something, and that leads me to one of the other topics that we asked if people wanted to learn more about , what can I do myself, without spending a fortune? So do you have any tips? You talked about damping now is there anything else that people can do?

Morten:

If you are a kind of do-it-yourself man, and not afraid of actually mocking around with the interiors… Christopher: Getting your hands dirty… Morten:

Yeah, getting your hands dirty. I would actually increase the damping in doors because look at it as a loudspeaker, the cabinet should be stiffed and damped and perhaps put some foam between the interior of the door and the plate of the door. It would actually keep it from rattling and that is one of the big issues in cars, that things get little loose and then they rattle.

Christopher:

From the front and...

Morten:

Yes, from the bass boost and then they come rattling starts. So, if you can put some damping material or some foam between the interior that will increase the performance.

Christopher:

Okay, and I have a question for myself because I remember that in my first car I had a head-unit where I could use you know the EQ. I could get plus 8 in bass and plus 8 in treble. Should I do that or should I stay I stay far, far away?

Morten:

When you do this, you kind of change things a lot. In a car like Volkswagen where we have tuned the system it should not be necessary, we have some settings that actually put some more fun into called dynamic and a little more bass and a little more playing rock music, and we have the authentic that is actually the most clean settings of them all, to put a lot of bass in , for some people they like that - but I would say changing the driver's in a standard, in your own car and that not being a Volkswagen and - add a little damping to the door that will increase the performance, I think.

Christopher:

Perfect! Thanks.

 

Christopher:

Craig, he has a three-way Dynaudio system in his car, Morten. And he feels like he has to, when he listens to them he has to crank up the power, for them to play really, really well. Is there any point to that or?

Morten:

Yes, actually he could, when he had some systems and some amplification, in the head unit, there could be a mismatch how the loudness functions integrated in his unit compared to his system now. One of the reason is that loudness is actually trying to increase the bass level of the sound when you are not playing it loud. But if that is out of the scale, then he will experience when playing louder, it will sound very good and that is because now you are out-sight the functionality of the loudness function. So I think what he should try to do is actually to perhaps increase the gain of his amplifier so he can shift the area for the loudness function, and align it properly. We do that in our cars. It is very, very important because if we do not do it correctly, then listening to music at very low level will actually sound a little bit thin, a little bit un-enthusiastic.

Christopher:

So Craig, go back home and check the loudness function, and amplifier again you said?

Morten:

Yeah, that could be a way to solve it. Actually if he could crank up the amplifier gain a little bit.

Christopher:

Okay. He had two more questions Morten. I would like first to talk about… One was if the driver set we use in cars are actually lower graded drivers than the ones we, for instance, choose in the home speakers?

Morten:

Naturally the construction is a little bit different. These ones in cars, are kind of optimized for weight because of lower weight better with mileage for the fuel but the driver system and the magnet-system and the voice coils and stuff are the same. So they are not downgraded by performance.

Christopher:

Okay, cool. And his final question was how many Watts do we actually use per channel?

Morten:

It is… In a car like the Passat, we are standing in front of here, they have a 16 channel amplifier and we know that for the woofers, they need more power so in this one, there is four channel with around 120 Watt in 8ohm and then there are the smaller channels for the mid-ranges and tweeters in a total of around 600 Watts.

Christopher:

So we specify each channel for the driver.

Morten:

And especially the woofers, they need more. So we have to boost some high power channels for the woofer channels.

Christopher:

Great!

 

Christopher:

That was a lot of really good questions, don’t you think Morten?

Morten:

Absolutely.

Christopher: But unfortunately, we are out of them now, so we are at the end. And I want to say thank you for joining us and taking time out of your schedule.

Morten:

You are welcome.

Christopher:

And as always guys, we truly appreciate you taking time out of your day to post questions to us. Thank you for watching.