12 replies to this topic

[SimpleHunk]

My friend would like to give me a PPI PRO 10 inch sub...... thirsty one.

Great sub as we all know, but it is in 8 ohm.

Base on ONLY ONE sub itself, can I make it to run at 4 ohm or 2 ohm by adding "something to it" ?

Or can I still yield good SQ out of it even it is 8 ohm?

Time is limited ( coz he is urging me to pick it up tonite), so pls pls pls give me some hint ....

Many thanks guys.

[paddles]

Im assuming its single coil? Not 4+4 by any chance??
You can still get great SQ I have a 6ohm sub, you will lose power and it wont be getting the most out of your amp (unless its a home theatre style one) but its still very usuable. You can re-wire coils, add another sub and do a few various other things, all of course cost money. So simple answer is you are stuck with it how it is without paying extra

[Stooge007]

check out the responses in this thread here:

http://www.caraudioaustralia.com/forums/vi...pic.php?t=41715

- Stooge007 out

[atmo]

More here:

http://www.caraudioaustralia.com/forums/vi...pic.php?t=38509
http://www.caraudioaustralia.com/forums/vi...pic.php?t=16072

The SQ wont be worse with an 8 ohm sub. It may actually sound a little better if you're using an amp with a lowish damping factor. You'll lose a little output (1.5-3db compared to a 4 ohm sub, depending on the amp), but in a SQ system it probably wont matter that much.

[SimpleHunk]

Will read them now ... and thanks to all respond at lightening speed.

to make is more clear, if I run it will use 400w RMS to it. ....
My mighty Mcintosh, or Nak PA2004 to run it (Bridged mode)

[SimpleHunk]

Atmo, 007, paddles - thanks for your reply.

I only know that 1/2 less current will go thought the sub coil, then 1/2 power to make the sub move. Can you (or anyone of course) tell me how much is 1.5-3.0db? i know it is decibel, but is that noticible when i m listening to music? I cannot visualise how "loud" it is for 3.0db. All i know is 6.0db increase is actually double the loudness.

Can i turn my gain up to compensate for it? will it hurt the amp?

I have a very basic picture now, that it wont hurt SQ (which is a blessing), but what else?

so I can also have peace of mind running a "supposed to be" 4 ohm amp at 8ohm all the time ?

Confused mind and pls :idea: me.

[micha3l]

400wrms!?!?!?

man, i had my xtant running with 250wrms and it got way loud, it could go louder than i could hack at normal listening, 400wrms is plenty!!!

[atmo]

A difference of 1db or less is impossible to pick. 3db is noticeable. 10db is regarded as being twice as loud. Any music player/sound editing software with a volume display or an eq that displays the ammount of boost/cut in db will be a good way for you to visualise and hear the difference at the same time.

To further add to what i said before, the 1.5-3db loss asumes two identical subs with the only difference being the voice coil impediance.

How loudly a sub plays depends on more than just that. The sensitivity and enclosure size and type also play a role, so if for example you're switching from a 4 ohm sub with a high sensitivity (above say 92db when fed 1 watt from a distance of 1 meter) in a ported box, to an 8 ohm sub with a lowish sensitivity (say 87db 1w/1m) in a sealed box, the drop in output could be up to 10db....or if the 4 ohm sub had a low sensitivity and the 8 ohm sub had a high sensitivity it may play louder than the 4 ohm sub. Without knowing all the paramaters, it's almost impossible to predict how much difference there will actually be.

[SimpleHunk]

Atmo & Michael, thanks again 1st. Now i know so many parameter come into the equation :!:

Just checked.

The beast is rated at 300w RMS and a sensitivity (SPL @ 1W) 88.1db.

23lb, hehe, bringing it around can omit my gym session !!!

Oh, very relieved to hear that 400rms is plenty, but then ( like a naive child now ), why ppl saying about whatever 1000w, 1500w, 2000w to run a sub? All those Class D? ( I played with Class D b4, dont sound good, no offence, dont shoot me )

I want to go sealed :roll: and small box, save space, tight bass. It actually supplied meansurement for 0.5,0.75 & 1 cu ft for reference. What size should I use ? I dont like boomy and loud, but i want the PUMP, and naturity.

Pls educate me more, and thanks again.

[@nThOnY]

SimpleHunk said:

Atmo & Michael, thanks again 1st. Now i know so many parameter come into the equation  :!:  

Just checked.

The beast is rated at 300w RMS and a sensitivity (SPL @ 1W) 88.1db.

23lb, hehe, bringing it around can omit my gym session !!!

Oh, very relieved to hear that 400rms is plenty, but then ( like a naive child now ), why ppl saying about whatever 1000w, 1500w, 2000w to run a sub? All those Class D? ( I played with Class D b4, dont sound good, no offence, dont shoot me   )

I want to go sealed  :roll: and small box, save space, tight bass. It actually supplied meansurement for 0.5,0.75 & 1 cu ft for reference. What size should I use ? I dont like boomy and loud, but i want the PUMP, and naturity.

Pls educate me more, and thanks again.

I have experimented to run my pair of Xtant x1044 (dual 4 ohm) subs in many different ways/amps and my finding is that less (power ) could be more.

When I first got my Xtant 1001 (class d), I wired both subs at 1 ohm (1000wrms at least) it is very loud and basically ruined the frontstage. After about 30 minutes of tuning, I decided to give up as I already got a headache from it.

Next I tried to wire up one sub at 2 ohms (still 1000wrms), it is slighter quieter (still very loud) but the sound still lack the accuracy I am after. So I gave up on that shortly afterwards.

Last thing I tried is to just hooked up the sub at 4ohm (500wrms). When I first played the music, the improvement in SQ is so noticeable, it is well balanced with the frontstage and sound so much more accurate, it is much easier to get it right as well. In terms of loudness (which I dun really care), everyone who have heard the system is surprised that it "has only 500wrms".

I have also used class AB amps like the Tube Driver 2150 and a Xtant x604 to run the subs too. I had my Tube driver Blue(2 ch, bridged to 600wrms) running one of my sub at 8 ohm (so it bascially gets around 300wrms). Wow, the most accurate and controlled sub sound I have ever heard in a car (almost, apart from the Velodynes and Phd, but not far away), it is suprisingly powerful too, consider that it is only 300wrms. I had this sub setup in my car for about 2 months before I go back to the Xtant.

So there you go, the best sub sound I have achieved is actually by using a hybrid tube amp with 300 wrms. I only go back to the Xtant because my system setup no longer allow me to use the tube driver, actually its my budget.

[SimpleHunk]

1st hand experience, cant be more honest, thanks @nthony.

IMO i actually think the same too. I have tried to hook up a ZXti 475 to 6.5 spilts and a 2 x MTX500D to JL 12w4 for my friend .... sounds POWERFUL, no SQ, but my friend is a young kid, he want it LOUD so ....

later ... MTX gave up and I just run everything from the PG, what an improvement, and now he stick with that setting no more class D.

If that is the case, then why we need class D ? What is the advantage of running Class D then apart it use less electricity ?

[Bassaholic]

SimpleHunk said:

What is the advantage of running Class D then apart it use less electricity ?

Efficiency is basically the only reason - but remember that more efficiency also gives other advantages, such as enabling you to use a smaller heat sink for the same power output etc

As far as the 8 ohm subwoofer goes, I would recommend trying it and finding out. 3dB is quite significant, but at the same time, a SQ system does not require all that much sub bass, so it may suit your needs fine.

[@nThOnY]

Slightly off topic but I find applying dynamat on the roof of my car really helps to improve the sub bass. Felt a bit skeptical when I was told but once the improvement is heard, there is no return.