# Why do modern cars silence the radio when starting? **URL:** \ **Category:** Factual Questions\ **Created:** [June 3, 2014, 3:57pm UTC](https://boards.straightdope.com/t/why-do-modern-cars-silence-the-radio-when-starting/689935 "2014-06-03T15:57:18Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![SpeedwayRyan](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@SpeedwayRyan](https://boards.straightdope.com/u/SpeedwayRyan)\ **Post date:** [June 5, 2014, 6:55pm UTC](https://boards.straightdope.com/t/why-do-modern-cars-silence-the-radio-when-starting/689935/21 "2014-06-05T18:55:14Z")
> [@Teuton](#): > > When you stop moving forward and put the car into neutral (it’s a manual, btw), it stops the engine. The engine then restarts when you put your foot on the clutch. This action does not cut the radio. Just noticed this part. That wouldn’t affect me much…I almost always leave the car in first with my foot on the clutch when stopped unless I know it’s a REALLY long light. If I knew the engine would have to restart, I’d honestly probably do it even less often than I do now. I know some people say that it wears out the throwout bearing faster, but the only time I’ve replaced a clutch it was just worn down, no throwout bearing problems ever…and I’ve driven manual-transmission cars exclusively (as daily drivers) for almost 20 years. Is there an override on this if you pull the parking break, BTW? ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [June 5, 2014, 7:19pm UTC](https://boards.straightdope.com/t/why-do-modern-cars-silence-the-radio-when-starting/689935/22 "2014-06-05T19:19:42Z")
> [@Rick](#): > > **Machine Elf** is it the headlights or the daytime running lights that stay on during crank? A lot of DRLs draw a bunch less current than headlights (particularly LEDs) No DRLs on my car, so yes, this is the main driving headlights. They are HIDs though, which I understand to be lower wattage than the typical incandescent headlight (something like 35 watts each instead of 55). If it matters, my car has a manual transmission, so maybe this is some kind of safety feature (i.e. if you stall the car in traffic, it keeps the headlights on during a restart)? ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [June 5, 2014, 7:52pm UTC](https://boards.straightdope.com/t/why-do-modern-cars-silence-the-radio-when-starting/689935/23 "2014-06-05T19:52:27Z")
It’s not about the battery really, it’s more about the weird sounds that come from the electronics in your car from starting and stopping. Loud pops are of the most concern because consumers will associate them with all sorts of bad things and these can get amplified and played out thru the cars speakers under the right circumstances. Some of the more advanced audio systems will time everything out in milliseconds so that you aren’t even aware that they powered down (or muted). Other more simple systems will just shut off to avoid sounds from coming thru the speakers. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [June 5, 2014, 8:14pm UTC](https://boards.straightdope.com/t/why-do-modern-cars-silence-the-radio-when-starting/689935/24 "2014-06-05T20:14:39Z")
> [@Rick](#): > > Back in the day (remember Gus?) cars with points had a resistor in the ignition circuit so the points didn’t run at full system voltage. This made the points last longer. During crank this ballast resistor was bypassed so the points got full available voltage. march 1958 ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [June 6, 2014, 4:28am UTC](https://boards.straightdope.com/t/why-do-modern-cars-silence-the-radio-when-starting/689935/25 "2014-06-06T04:28:33Z")
> [@Machine\_Elf](#): > > No DRLs on my car, so yes, this is the main driving headlights. They are HIDs though, which I understand to be lower wattage than the typical incandescent headlight (something like 35 watts each instead of 55). > > If it matters, my car has a manual transmission, so maybe this is some kind of safety feature (i.e. if you stall the car in traffic, it keeps the headlights on during a restart)? There is your answer, it’s the HIDs. First off they draw a LOT less current and secondly they really don’t like going on and off a lot. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [June 6, 2014, 4:29am UTC](https://boards.straightdope.com/t/why-do-modern-cars-silence-the-radio-when-starting/689935/26 "2014-06-06T04:29:37Z")
> [@Si\_Amigo](#): > > It’s not about the battery really, it’s more about the weird sounds that come from the electronics in your car from starting and stopping. Loud pops are of the most concern because consumers will associate them with all sorts of bad things and these can get amplified and played out thru the cars speakers under the right circumstances. Some of the more advanced audio systems will time everything out in milliseconds so that you aren’t even aware that they powered down (or muted). Other more simple systems will just shut off to avoid sounds from coming thru the speakers. Got a cite for that? ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [June 6, 2014, 2:15pm UTC](https://boards.straightdope.com/t/why-do-modern-cars-silence-the-radio-when-starting/689935/27 "2014-06-06T14:15:42Z")
> [@Rick](#): > > Got a cite for that? Experiance. I work with suppliers of infotainment systems to all of the major car manufacters. Cannot go into specifics as these are considered not secerts but tricks of the trade. ---
**Author:** ![Teuton](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/teuton/32/3864_2.png) [@Teuton](https://boards.straightdope.com/u/Teuton)\ **Post date:** [June 6, 2014, 4:13pm UTC](https://boards.straightdope.com/t/why-do-modern-cars-silence-the-radio-when-starting/689935/28 "2014-06-06T16:13:00Z")
> [@SpeedwayRyan](#): > > Is there an override on this if you pull the parking break, BTW? The state of the parking brake (which is also an electronic switch, rather than a lever, on this car - it also has an auto-hold system which takes a bit of getting used to) has no bearing on whether the auto-stop system is engaged or not. You can also turn the auto-stop system off if you want. I have done it once in a long, slow traffic queue - when you’re rolling forward a few feet and then stopping, having the engine die every few seconds get old. I quite like the auto-stop system, because it saves me £400 a year on company car tax. [Previous page](https://boards.straightdope.com/t/why-do-modern-cars-silence-the-radio-when-starting/689935.md?page=1)