85 replies to this topic

[shiny_car]

Experiment.

The Bass Blocker might be a shallow 6dB/oct slope, meaning it works very gradually so the speakers still play some bass. I would expect the sub can have a LP set at 100Hz.

[President Obama]

I only just realised that my speakers are under powered for the amp. 40 rms, amp provides 60rms, so I think its time for them to go. I was looking at the door speakers and their mounting depth is still to deep at 2.5" so I'm going to be sticking to the 6x9's again. I'm thinking about getting these: http://www.soundmast...akers/CSHX6948/ Any negatives? apart from the fact they're not door speakers.

[shiny_car]

Is the system up and running? If not, my advice is 'stop focusing on the specs, and listen to the performance'.

I recommend changing speakers if the current ones do not sound good enough. And I recommend a more powerful amp if it's not loud enough. However, if it sounds good, and goes loud enough, you're probably wasting money by changing things just because the specs appear misaligned. This generally doesn't matter.

[President Obama]

Yeah its up and running, should of mentioned that. The reason I want to get some better speakers is because the bass currently drowns out everything. Like on the head unit I have it set to 0 and the speakers set to 6+ and it still drowns em out. I have the gain near max on the sub with no distortion, but because of the bass going to the speakers I only can set the gain on the speakers to a little less the half way.

[shiny_car]

Have you tried reducing the gain for the sub, and allowing the speakers to go louder? Of course, you need the HP filters/bass blockers, otherwise 'any' speaker will distort when you turn up very loudly.

[President Obama]

Well when I was tuning it I turned the gain down a fair bit but then I felt like I lost a lot of bass, its really hard to tell with the seat off. The seat makes such a difference to the sound.

Anyway I'm going to get the bassblockers for 125hz I think since thats what the head unit's max is and it still sounds good then. Another question, since I don't like how exposed my sub is (no grille) will any 10" grille fit it? Or does it have to be one made to fit it?

Edited by President Obama, 15 February 2012 - 07:44 PM.

[shiny_car]

The 'loss of bass' is presumably only relative. I mean, you can turn the volume up louder, and the same loud subbass will return. The aim is to balance/blend the subbass with the speakers, which you've suggested isn't the case, cos you have too much subbass.

What 'slope' do the bass blockers offer? An amplifier typically has 12dB/oct xover slopes. So they filter out the bass fairly quickly. In case you don't realise, xover filters are not 'brick walls', and don't cut off the bass suddenly; they gradually filter out the bass, and how quickly is defined by this slope.

If the bass blocker is simply an inline capacitor (which is what I suspect), then it will be a shallow 6dB/oct slope, and only work very gradually. So a 125Hz blocker will still have a lot of subbass going to the speakers. This is why I recommended a 200Hz version, if it's a 6dB/oct slope.

If you don't understand this concept, have a read here: http://www.bcae1.com/xovrslop.htm It's an important concept.

If the bass blockers are 12dB/oct, no probs.

The diameter of 'any' grill for a 10" sub should be fine. The potential problem is how much cone excursion the sub offers, and whether there's enough space behind the grill for the cone to move, without hitting the grill. Grills should suit most subs fine; only those subs with very high excursion could be an issue (25mm+).

[President Obama]

yeah I didn't really understand the slope, I knew there was some kind of slope but didn't really get the dB thing. I also looked up how the whole capacitor thing worked which makes a lot more sense to me now. So I think I will go back to your original idea of getting a capacitor from jaycar:

http://www.jaycar.co...or&form=KEYWORD

When I first saw it I didn't understand how it worked and just dismissed it. Stupid me as now I'm going back to it. So with these I just cut the positive wire to the speakers then solder one of these inline for each speaker?

Also I decided to look around after emailing the guy on ebay about some getting some custom made ones and he hasn't replied for nearly 2 days now.

Just looking at the ebay page he has the specs for his 180hz bass blockers:

Effective attenuation (muting):
-6dB @ 90 hz
-12dB @ 45 hz
-18dB (Full attenuation) @ 23 hz
Which makes me wonder if 200hz is high enough? These are 6/db slope.

Just found this calculator thingy:
http://www.bcae1.com/xoorder.htm

but I think it only works on a 12/dB slope but anyway it said I should need a 318mf capacitor. Ill let you comment lol.

Also another random question, I'm replacing the light in the cab with hopefully something much brighter as atm it does nothing in complete darkness. Its just a normal globe. I'm thinking of replacing it with this led one will it make much of a difference?:
http://www.jaycar.co...84&form=KEYWORD

Edited by President Obama, 16 February 2012 - 08:39 PM.

[shiny_car]

President Obama, on 16 February 2012 - 07:06 PM, said:

So with these I just cut the positive wire to the speakers then solder one of these inline for each speaker?

Yeah, that's it. When you understand the concepts, it makes sense, eh?!

You can put the capacitor anywhere along the wire, wherever it's convenient. Just secure it somewhere (eg: cable-tie it to the frame of the speaker if it fits), so that the join is not under tension, and insulate any exposed wiring to prevent short circuits.

Quote

Just looking at the ebay page he has the specs for his 180hz bass blockers:

Effective attenuation (muting):
-6dB @ 90 hz
-12dB @ 45 hz
-18dB (Full attenuation) @ 23 hz
Which makes me wonder if 200hz is high enough? These are 6/db slope.

Cool, I suspected they may be 6dB/oct, just cos they are cheap and simple.

200Hz is a reasonable cut-off point. It also depends what value capacitors are available. The next-value cap that Jaycar offers is 150uF, and that will provide a cut-off point at around 250Hz, so that would also be very reasonable.

This is a table I have saved, for reference (eg: it says, to achieve a 200Hz 6dB/oct slope with a 4ohm speaker, the cap would need to be 198.94uF cap...close enough to 200uF):

 passive xover table - 6dB (hertz).gif   23.67K   3 downloads

Quote

Just found this calculator thingy:
http://www.bcae1.com/xoorder.htm

but I think it only works on a 12/dB slope but anyway it said I should need a 318mf capacitor. Ill let you comment lol.

To create a 12dB/oct slope, you need to add an 'inductor/coil' to the capacitor; the cap is wired in series (inline, like we described), and the coil is wired in parallel (ie: joins between the positive and negative speakerwires). It's not difficult if you wish to do it, but you can see that the cost quickly adds-up, and probably not worth it.

So you could add a 9mH inductor to a 200uF cap, and achieve a HP filter that's close to 100Hz 12dB/oct.
http://www.jaycar.co...w.asp?ID=LF1336

This is a 12dB/oct reference table:
 passive xover table - 12dB (hertz).gif   23.07K   1 downloads

Quote

Also another random question, I'm replacing the light in the cab with hopefully something much brighter as atm it does nothing in complete darkness. Its just a normal globe. I'm thinking of replacing it with this led one will it make much of a difference?:
http://www.jaycar.co...84&form=KEYWORD

LED festoons can work quite well. Though not always brighter than a normal filament globe; but you might prefer the colour of an LED (blue-white). I have tried them before, and the festoons I used were not very good, and were not as bright and too blue for my liking. I didn't bother trying different brands/designs.

I don't think LEDs work if your car has a 'dimming' interior light.

[President Obama]

I went to jaycar today and got the capacitors, unfortunately they only had 220uF and said the one on the site is listed wrong, but that could of been the sales guy bullcrapting me. I still got 2 of them anyway and I'm going to put them in the system tomorrow. Also just looking at this thread I totally forgot about getting the LED light oh well. Which is funny because I was looking for a LED spotlight you think it would of poped into my head.

Does it matter where I put them inline? Like should I put it right off the amp or anywhere in cable or right on the speaker, I don't think it would make much of a difference would it?

Edited by President Obama, 22 February 2012 - 07:56 PM.

[shiny_car]

It doesn't matter where you put them.