[zoltan]

Hello everyone...

I have a 98 Formula and it has an after market audio system. The head unit is a Pioneer, it's fairly new, with bluetooth and lots of goodies.

I have Polk 6.5" component speakers (100 WATTS RMS) up the front in the doors and the same will be coming into the back (middle of the car) soon, I'll be putting the woofers in the middle then putting the tweeters up the back.

At the moment, I have a big issue with higher volume music. With the t-tops off, on a highway, I need the volume up. The music I listen to in normally powerful rock music, but I like a bit of everything.

When the volume is up, I get distortion - especially with the bass. I've spent a lot of time trying to tune it. The only way I can reduce the distortion in the bass is to reduce the SLA (sound level adjustment), but this means less volume.

I have been told various things in order to resolve the issue... one person suggested using an amp, the other person said I can achieve the same solution by using a head unit that puts out more voltage power.

The general consensus is that there is not enough power to work these speakers off the head unit I have right now.

What's your opinion?

 

[sea dog]

The problem seems to me to be, your over driving your amplifier with bass turned up. Driving the amp high enough to clip the waves and make square waves will blow speakers.

Your solution is to get a more powerful amplifier to reproduce the strong bass you prefer without distortion. Keep in mind that amp power increase is not a linear event.

Every time you double the power of your amp, given the same speaker setup, you do not double the volume. You only increase the volume 3 decibels.

As an example, say you have a 25 watt per channel amp in your set up. If you go to 50 watts per channel, your volume goes up 3 decibels. For the next 3 decibel increase in volume, you would have to go to a 100 watt per ch amp. And for another 3 decibels, a 200 watt per ch amp would be needed.

Another aspect of volume would be your speaker setup. Good quality speakers will have in their specs, the amount of decibels the speaker will put out with 1 watt input @ 3 feet away.

Much can be gained by using more efficient speakers that can still handle the amount of power your amp puts out.

Example, say your speakers put out 80 decibels @ 1 watt. Buying a set of speakers that put out 90 decibels @ 1 watt would increase your volume over the less efficient speakers.

So in the end, a combination of more powerful amplifier, and more efficient speakers will make your music more enjoyable.

And don't worry about too much power blowing speakers. What blows good quality speakers is driving them to clipping. I've been using a set of Jbl home speakers rated at 60 watts on my home stereo for years. My amp puts out 300 watts per channel. I've never blown a speaker in about 20 years of use.

Because I make sure I never drive the speakers into clipping.

 

[zoltan]

Sorry, I did not mention it... I currently don't have an amp (none whatsoever)

The speakers I have are 100 Watts RMS each

If an amp will resolve the issue, what would you recommend (keep in mind the limited space in this car... there is not much room for anything here...)

What specs should I look for? Would you know of something small enough so that it's not visible and will provide the correct power for the speakers?

 

[GaryDoug]

I would have thought that a Formula would have had the Monsoon sound system, but maybe not. Make sure you do not already have an amp in the hatch area just ahead of the spare tire. It is not obvious by appearance, just looks like a triangular flat box. If you already have the amp and it's connected, the speakers in the door should be 2 ohms and ones in the sail panel should be 4 ohms with dual voice coils..

 

[zoltan]

I doubt that the amp is there and if so, it won't be connected. The head unit and front door speakers are all after market, 4 ohm 6.5" component speakers, I'm going to put the same in the rear.

If I do find the amp, I'm guessing by the comments that it would not be good enough anyway... so any recommendations on what I should get and what will fit - hidden from view would be best.

Thanks guys

 

[GaryDoug]

The point is that the wiring may still go to the amp if it's there. The spare tire has been removed in this photo.

 

[zoltan]

GaryDoug,

I will take a look tomorrow... my car has had a lot of wiring changes in it's life. Apart from the steering conversion (to right hand drive) then there was a bit of re-wiring done with the change of speakers and after market head unit.

I don't know how it's all going to come together... even if there is wiring to where the amp used to be, then there would still be a need to wiring back from there to the speakers and at the moment, I think it's all coming from the head unit.

It's frustrating... I've had one person suggest a replacement head unit - same brand, one that has more voltage output... the other person tell me I need an amp (both from the same audio shop).

It would be much easier if there is a head unit solution, then I don't need to worry about wiring up and hiding an amp, but if the amp is the solution, then I need some advice on finding a suitable one that fits in without it being visible... I honestly don't know what's best??

 

[ZumpTA]

SeaDog is correct in what he said. To put it into even simpler terms, to double the volume, you need 10 times the power.

Head units have high distortion for starters. Pro Audio NEVER uses the decks amp, always external. To properly drive any speaker, it needs amplified by its function. No one speaker can produce ALL FREQUENCIES at once, that is exactly why we use a crossover to separate the frequencies. Remember, all a speaker does is VIBRATE air. Imagine trying to produce the sound of a high-hat at 16,000Hz (vibrations per second) a voice (between 250Hz and 2,000Hz) a kick drum in the 200Hz range, and a bassline somewhere around 80Hz. ...all at the same exact second. It simply cant be done. that is where the distortion comes from and how coils get burnt.

Highs to the tweeters, mids to the midrange, midbass to woofers, low frequency bass to the subwoofers.

If your head unit has a subwoofer output, USE IT! Activate the RCA output in settings, set the frequency to 100Hz or lower, plug an amp into it, and add a sub in the trunk. Set your midrange frequencies in settings to be ABOVE 100Hz and lower the bass setting on the deck to below half (about 25%). Just taking the low frequyency bass out of the signal goes a long way.

I'm currently using a $125 Kenwood Excelon head unit, an old $150 250w MTX Thunder amp and 2 cheap ass aluminum cone vvofenhag 12" subs. Midrange and highs are coming out of my factory speakers in the door and trunk driven by the head unit at 75w/ea. Bass below 100Hz from the subs in the trunk, sounds great. Some tracks, I cant pull enough bass out of the system, most tracks are happy with my preferred setting, and for classic rock suuch as Zepp Floyd, or Sabbath, I have to go from 25% bass to 75%. ...but I listen ti it all, Rat Pack, Classic Rock, Rock, Drum and Bass, Jungle, Dubstep, Trap, Rap, and Jazz.

Look into your head unit and see if it has a sub-out. if not, you'll need an amp with a low-pass filter and a subwoofer.

...the features on the head unit will dictate which way to go. The whole point of the exercise is to get the low frequencies away from all the components and onto a proper driver..

 

[sea dog]

You do have an amplifier. It's built into the head unit. As Tony has stated, to get the kind of bass and overall performance you are looking for, you will need an upgrade.

 

[Kenji]

Zoltan, how did you fit the 6,5" Polk Audio speakers in the door?

I have a set too and want to put them in, I'm just curious if it's a lot of work...

 

[zoltan]

Sea Dog, what I mean is that I don't have an external amp, not even the original.

Hey Kenji, sorry about the delay in responding to your question.

The woofer sits in the place of where the original woofers did - I think it was a little tight, if I remember correctly, there was some removal of factory plastic, I think the back surround section?? But nothing major is required to fit them. The tweeters where a breeze.

The only real challenge was finding a place for the splitter box. I wanted to have this in the door, with the speakers. I found the best place for this was actually at the top front of the door, inside the door skin. I also thought that this was the best place for it not to get wet from any water that may enter the door area.

It's not a major drama getting it all in...

 

[ZumpTA]

...a better location would have been the kick panels, or up in the dash under the steering wheel and behind the glove box.

The doors get a lot of elemental exposure, experence rapid thermal cycles, and crazy vibration/shock compared to the interior.

It (the components crossover) isn't going to die anytime soon, but, it isn't going to have a lengthy life span either in that environment.

 

[zoltan]

Ok guys, I have my eyes on an Amp, but it's size is:

Chassis size (W x H x D)

265 x 60 x 200mm

So, the $64,000 question is - where can I locate it without it being visible and without losing boot space???

 

[ZumpTA]

Something that small can easily fit in the little cubbie hole on the left side of the trunk. Or, when you get a subwoofer, mounted on that side of the box. As long as it can breathe, it's OK.

At one point, I had created a board that mounted in the spare tire well and mounted 2 amps and a crossover there. ...but as I said about the doors, not a very hospitable environment. Best kept inside.

 

[zoltan]

Well, this might require some careful planning... I don't want to lose any boot space. I'm not going to get a sub, for the same reason, lack of space. I often take the kids out on the weekends, need as much space in the car as possible.