147 sound research

[BenzinaBrera]

Hi, im considering upgrading the sound in my 147 JTDM, at the moment most music only make it up to 42 on the head unit then the distirtion/rattle sound comes in, at this sound level my 159's sound system just started coming alive! so you could imagine my dissapointment in the 147.

Now i wanted to know, what is the RMS the 159 actually puts out, because it sounded pretty impressive vs the 147.

and secondly i was thinking about setting up the 147 with Boston Acoustics SE60 split systems in the back and front with a amp to power it. but with the standard head unit in tact and ofcourse dynamat and foam.

im not looking at spending jaw dropping money and getting pavement pounder sound, i just would like it like my good 'ol 159 was but the question is would my planned setup be enough?

for those who dont know the 159 has rich bass but crystal clear treble also, was always a pleasure to turn up.

ps. not the 147 or 159 has or had BOSE

[shiny_car]

Whilst I don't know the specified RMS power output, I would expect it is similar to other headunits, and around 20WRMS or 4x40W peak. Regardless, the quality is nothing great. (BOSE is something like 50WRMS per speaker channel, and 100WRMS for the sub.)

The reasons for distortion are usually 2-fold:
1. amplifier clipping/distorting
2. speakers reaching maximum mechanical limits

It is probably the cones reaching max excursion (mechanical limits), rather than the headunit clipping. Reason being, there is no highpass filter, so the speakers are being fed all the bass (incl subbass).

Adding an amplifier, even to existing speakers, can greatly improve performance. Not only for the higher clarity and more power, but because you can utilise the highpass filter built into nearly all amps. Take away the subbass, and the speakers will have far greater power handling limits, plus sound clearer too.

There's no good reason to upgrade rear speakers, unless you consider it important to cater for rear passengers. That is what rear speakers are primarily for. If you're usually alone in the car, then focus on the front speakers; spend double the amount on them, instead of having rears. Or spend the money elsewhere.

Boston Pro60SE speakers? Very high quality, and far better than what most people install. Definitely worth having a quality amplifier and sound deaden the front doors, in particular to seal over the multiple open service holes in the doors. This is another reason the 159 has far better sound quality: the doors are already sealed over with a factory metal panel. In the 147/GT, the doors are full of holes, losing all your bass/clarity.

Properly installed and tuned, those speakers alone would be enough for most people. Of course, they still won't produce decent subbass, so you'll be missing much of the lowest 2 octaves of music.

[BenzinaBrera]

Oooh I see thanks! You are a treasure cove of wisdom in ice I see! With what will tou reccomend i seal the service holes? Also do you think using the grey foam with dynamat will reproduce better sound than just dynamat?

Oh yes and like I said im not looking at getting sub bass via subwoofers etc, I just want my 159's level of sound quality back, do you think this setup will match my 159 again?

[BenzinaBrera]

Ive been looking at an Orion amp, a west coast customs one, it pushes 60w rms per channel at 4 ohms which is 5w more than the Boston acoustics rated 55w, am I correct in saying that fact that its slightly overpowering is better for the amp because its working under less strain and the speakers can always then perform at maximum effeciency?

[shiny_car]

Originally Posted by Benzina159

With what will tou reccomend i seal the service holes? Also do you think using the grey foam with dynamat will reproduce better sound than just dynamat?

Easiest method to seal the holes is use self-adhesive sound deadener (eg: Dynamat Xtreme) and stick over the holes. It is fairly rigid, and will work very well. If you have time and strive for perfection, then first cut out solid panels to cover each hole (eg: 3mm mdf wood; aluminium; hard plastic), place them over each hole, and then cover with Dynamat; it will be even more rigid. Like this: http://pic20.picturetrail.com/VOL97/.../314773594.jpg

Dynaliner (grey foam) is not designed for doors because it is not self-adhesive; though you could place it behind the door trims (not inside the cavity). It is best used underneath your carpet and in the boot IF you choose to use it.

Adding a Dynapad behind the woofer provides negligible benefit. Not worth it unless you are a perfectionist entering competition.

Originally Posted by Benzina159

Ive been looking at an Orion amp, a west coast customs one, it pushes 60w rms per channel at 4 ohms which is 5w more than the Boston acoustics rated 55w, am I correct in saying that fact that its slightly overpowering is better for the amp because its working under less strain and the speakers can always then perform at maximum effeciency?

That amp would be ok. Are they Boston Pro60SE speakers? These are 3ohm, so the amplifier will produce a little more power.

Having more power than required can be helpful, to provide better dynamics because of more reserve power, even if you don't use it all. However, only relevant if you play it very loudly; normal volumes might only require 20-30WRMS.

[alfa_147_jtd_16v]

Originally Posted by shiny_car

There's no good reason to upgrade rear speakers, unless you consider it important to cater for rear passengers. That is what rear speakers are primarily for. If you're usually alone in the car, then focus on the front speakers; spend double the amount on them, instead of having rears. Or spend the money elsewhere.

I know you always say that siny, but I've found the rear speakers make a huge difference. If you drop the fader towards the front, the quality of the sound is really poor and I've noticed this with the 3 cars I've owned. I personally don't agree with just changing the fronts. If your going to change the fronts then I'd do the rears too.

[BenzinaBrera]

thanks for the advise shiny, i think ill leave the foam then but definately cover the holes with dynamat, erm the bostons im looking at is 4ohm, and i think its just se60, not the pro version.

will they be fairly worse than the pros?

Ive been looking at them on Soundmatch Car Audio Wholesalers if you want to go check it out for yourself.
you can also find the amp here: WestCoastCustoms 600w 4ch amp - Autostyle Motorsport

[shiny_car]

Originally Posted by alfa_147_jtd_16v

I know you always say that siny, but I've found the rear speakers make a huge difference.

Yes, indeed I say it. I think people put too much emphasis on upgrading rear speakers when the value-for-money isn't there in terms of performance gain.

Granted, I definitely accept that some people like to hear music behind them, as if to create a 'surround' effect. However, I find this unrealistic (ie: not lifelike), to hear music from behind, which is where my strong bias arises from (which in turn stems from competition). Doesn't make it right, of course, I admit.

At the end of the day, if there is a fixed budget to work with, upgrading the rears is a low priority IMO. Far better to spend the money on the best front speakers you can afford, and have them installed properly for best effect. Rear speakers - in the form of factory speakers - can still exist and operate.

Originally Posted by Benzina159

thanks for the advise shiny, i think ill leave the foam then but definately cover the holes with dynamat, erm the bostons im looking at is 4ohm, and i think its just se60, not the pro version.

Ah, my mistake then. I've now checked the website: SE is a new series I've not seen before, between the S and SC (which are pre-existing). It makes them 'good entry level' rather than the very high quality of the Pro series.

Everything we've discussed still stands. If you decide against upgrading the rears, then you might look at the SC60 speakers instead. Best to audition first, to ensure you like the performance of any of the speakers you're considering.

The amp looks very adequate. There's far less difference in quality between amplifiers compared with speakers.

[BenzinaBrera]

I see, well dont hate me but im also one of those people who enjoy the full 4 speaker effect

Unfortunately there are very few places around that show you a live demo of the speakers and even if I wanted to fit boston sc's I cant manage to find any around.

Im also considering buying alpine speakers thats rated at a higher rms but I dont know if they are better or similar quality?

All in all do you think any of these 2 types of speakers will be as good or better than my 159 along with some dynamatting?

The alpines im looking at are alpine SPG-17CS and are rated at 70w rms. Obviously ill upgrade the amp then also.

What do you think?

[shiny_car]

Power handling doesn't tell you how good a speaker sounds. Doesn't even tell you how loudly they will go. So you can't rely on those at all.

If not Boston, I suggest searching around to compare with Focal, DLS, Morel, JL Audio, Diamond Audio, Hertz. Just some examples of good speakers at this pricepoint. Off an amplifier, and IF installed properly, they will easily sound better than the factory 159 setup.

Hearing rears is ok. But you don't need to spend money upgrading them IMO. You only have to listen to a really high quality incar stereo, and you'll realise rears are not required at all. You can achieve a 3D/lifelike wall of sound front fronts + sub.

[BenzinaBrera]

thank, yes i know the power handling isnt the main thing that matters, thats why i asked you if you think they are also good quality

Well i think that settles it then, ill go for the bostons with orion amp, one last thing, you said IF installed properly and now im paranoid so please tell me what a proper install is in your opinion so that i can make sure i do it right thanks for all the advise

i have to sort out the servicing, bumper spraying and some other small issues on it then im going to do this sound, ill be sure to post some piccies and dont worry i wont just dissepear, ive been on the forum for almost 2 years and i share news like your all family haha! so ill be sure to brag a bit when i install my sound system, it might be helpful in the future for someone else who are also just looking for a basic but quality upgrade.

[shiny_car]

Originally Posted by Benzina159

one last thing, you said IF installed properly and now im paranoid so please tell me what a proper install is in your opinion so that i can make sure i do it right

With the 6.5" woofers, I suggest removing the factory plastic speaker ring, and cutting a new one from mdf or marine ply wood. Measure carefully, and make it the right thickness so that the front of the speaker frame sits nicely behind the grill; I recall measuring the depth of the factory speakers in my GT, which was around 41~42mm from the metal door to the front of the speaker frame. So if the speaker frame is around 3mm thick, make a ring that's 39mm thick (eg: 18+18+3mm thick pieces laminated/joined). You can cut the ring to the exact required diameter and cut-out, and secure firmly to the door. Might want to use some thin closed-cell foam rubber to cut out gasket rings to sandwich between the ring and door, and speaker and ring.

Cover those service holes with Dynamat/sound deadener. Also add some directly behind the speaker inside the door cavity. A solid, 'sealed' door, with solidly mounted woofer will make a big difference. You can't seal the door 100%; the drain holes at the bottom need to be left open, and the window seals are not airtight.

Experiment with tweeter position and angle. You could settle for the factory positions for the factory look, but they probably sound better on the A-pillars, or dashtop in the corners, or side mirror triangular sail panels; or some people prefer them down in the kickpanel areas (near your feet) angled upwards.

I have a photolog for my GT. You don't have to go to this extreme, but it give an idea of what I am referring to: PictureTrail: Online Photo Sharing, Social Network, Image Hosting, Online Photo Albums

[alfa_147_jtd_16v]

The other thing by not replacing the rears, is surely not only the effect in quality (as the rears won't have the same quality if left stock) but also the power handling. If you are going to add an up etc the stock rear speakers are really going to struggle to keep of with the fronts are they not?

[shiny_car]

Depends how loud you want the rears. I disconnected the rears in my GT, and there are none in the 155. If you have them, I normally suggest 'fading' mostly to the front, and having rears 'only just' audible for some 'fill'. This way, they are only fed minimal power (maybe 5WRMS) which they can easily handle, and don't adversely affect sound quality (though they steer the soundstage rearward, which is what I don't like about rear speakers).

Of course, if you want them as loud as the front, you'll need to run them with a highpass filter (off an amp) and upgrade them.

Music is 2-channel 'stereo', as opposed to DVD-A 5.1 with discrete rear channel 'information'. This is partly my reason to dislike hearing rear speakers. You only need the front speakers to achieve 'stereo' music (and sub). But again, each to their own.

[BenzinaBrera]

wow shiny! i never thought a aftermarket single din would look good in there but yours looks tops!

Also where did you manage to find that custom GT replacement plasitic in the center console? i would like to fit a boost and oil temp guage there on my JTDM, ever since owning the 159 i have oil temp guage issues haha!

[shiny_car]

Everything I custom made.

[BenzinaBrera]

very proffesional maybe ill order some stuff from you, because im lazy like that hehe id like 4 wooden speaker rings and the centre cover please

[shiny_car]