6x9 car speakers have great potential to play good hard hitting bass that's loud because they have a large amount of cone surface area. 6x9 car speakers are a simple solution to add bass into your car, without buying a subwoofer enclosure and car amplifier.
Below are some excellent tips to get more bass out of your 6x9 speakers:
1)Place them in a enclosure, instead of them fitted in the rear parcel shelf. A enclosure will enhance the 6x9 speaker's ability to play a more range of bass frequencies. You can either buy a premade 6x9 speaker enclosure off the shelf or built your own custom enclosure.
2)If you have a stock car stereo, i suggest you upgrade it to a aftermarket stereo. Aftermarket stereos offer more sound quality and let you have more control of the sound.
2)Tweak up the bass from your car head units settings. I recommend you turn down the treble all the way down and increase the bass level to the maximum level. Insert a bass test CD and see if you windows are shaking!
3)Amp up your 6x9 speakers to the suggest rms watts rating. Amping them up will make the bass sounder louder and also suggest you to set the low pass filter to 50 hz. Setting a low pass filter on your 6x9 speakers, will turn them into subwoofers, because they will only produce bass. If you set the low pass filter on the 6x9 speakers, they will not produce mid range and high sounds. But you can use your front set of car speakers, for the mid range and high frequencies, so don't worry.