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Infinity Perfect, underwhelming ?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=55768
Printed Date: March 29, 2024 at 6:07 AM


Topic: Infinity Perfect, underwhelming ?

Posted By: jdog0411
Subject: Infinity Perfect, underwhelming ?
Date Posted: May 15, 2005 at 1:13 AM

I spent the entire day completing my box construction and hooking up my new Infinity sub and MTX 421D amp in my Explorer. The sub is a perfect 12 SVC at 4 ohms, and the box I put it in is a 1 cubic foot sealed enclosure stuffed with polyfill and airtight.

I hooked it all up and turned on the system tonight with the amp set at factory settings and tried to play some songs with lots of bass in them, and at first I didn't even think the sub was functioning. It didn't sound like anything was coming from it, and I could feel no vibrations when I touched the woofer. After some fiddling, I turned the gain up on the amp, and added some bass boost, and made sure my crossover was set at around 80hz. I turned up the volujme on the headunit, and there was some bass, but not really what I was expecting. At least I could tell the woofer was functioning, because the cone was vibrating slightly. There was no visible excursion. I was able to get some increased bass response to where there was output from the sub, but I never really got nearly the response I was hoping for. A couple of things I'm thinking are:

the amp is not overly powerful, putting out 210 watts (spec) RMS at 4 ohms at 14 volt DC, and only 150 watts RMS at 12 volt DC. There would be significantly more power if I was running the amp into a 2 ohm load (300 watts RMS at 12 volt DC and 421 watts RMS at 14 volt DC). I'm stuck with a 4 ohm load because my sub is single voice coil. My first question would be, how do I find out how many volts DC I have going to the amp? Maybe I am only seeing 150 watts RMS and the sub is way underpowered. Even if this was the case, others on this forum have told me they have 100 watts or so going to their Perfect subs and it is still putting out high bass output.

I believe I have everything wired correctly, so I don't think that is a problem. It's possible that the sub just doesn't have enough juice going to it and the combination of that and it being in a small sealed enclosure is making it kind of anemic. I want SQ over raw boom, but from what I have heard about the perfects, I just think I should be getting substantially more output from the sub than I am getting. Granted, I haven't played with the amp settings much or even played the sub very much yet, but any ideas or suggestions on what may be holding it back would be appreciated. Thanks!



-------------
2004 BMW 325ci.
Alpine CDA-9885
JL 300/4 and 250/1
JL XR 5.25 comps
Infinity Kappa Perfect 12




Replies:

Posted By: OhioMike1101
Date Posted: May 15, 2005 at 1:20 AM
Did you turn the sub on in the deck?  Did you play with the sub settings on the deck?




Posted By: racer427
Date Posted: May 15, 2005 at 1:30 AM

First off, you need to get the gains set correctly.

Second, are you using and external crossover or does the headunit have a built in crossover?

Third, what are your pre out's rated at voltage wise?

Chris



-------------
Alpine CDA-9833 HU
Diamond Audio M661 Components
MTX Thunder T6.6 Components:rear fill:
Cadence Q400 4 Channel Mains + rears
Thunder 801D Subs
MTX 1004 10's
Dual 4g wire to rear
4g grounds




Posted By: jdog0411
Date Posted: May 15, 2005 at 1:33 AM

Yes, from what I know of my deck (Pioneer DEH-7600mp), I have the sub turned on. There are two settings, "rear speakers" which can be full or subwoofer" and "preout" which can be full or subwoofer. I have the rear speaker setting to full because that channel is my rear door speakers, and the pre-out to subwoofer. I believe I have it set ok on the head unit, but anyone familiar with Pioneers, or this unit in particular, please chime in.

I know the box is usually a culprit with a situation like this,  but Infinity recommends a 1 cubic foot sealed enclosure, and that is what I have it in. I just find it odd that it doesn't sound much if any louder than the basslink I had in before. I just wonder if there is something I'm missing. I don't think there are any connection problems, since I am getting output from the sub, just not as much bass as I thought I would get, even on very bassy songs. It almost sounds like half the bass i'm getting is coming from my kappas in the doors.



-------------
2004 BMW 325ci.
Alpine CDA-9885
JL 300/4 and 250/1
JL XR 5.25 comps
Infinity Kappa Perfect 12





Posted By: jdog0411
Date Posted: May 15, 2005 at 1:41 AM
racer427 wrote:

First off, you need to get the gains set correctly.

Second, are you using and external crossover or does the headunit have a built in crossover?

Third, what are your pre out's rated at voltage wise?

Chris


Hey Chris, I was hoping you would chime in........I finished the install late tonight, so I didn't have much chance to get the gain set on the amp. i will try to do that properly in the morning. The headunit has a high pass filter setting, that I have set to 125 hz, and it also has a "S/W" setting (which I assume is the low pass filter) that I have set to 80hz. The amp also has a continuously variable crossover. It is not graduated, so I don't know exactly what it is set to. Not sure which of the two I should use, I assume I shouldn't be using both.

According to the head unit manual, the pre-out max voltage output level is 2.2 volts.



-------------
2004 BMW 325ci.
Alpine CDA-9885
JL 300/4 and 250/1
JL XR 5.25 comps
Infinity Kappa Perfect 12





Posted By: racer427
Date Posted: May 15, 2005 at 2:03 AM

Ok, well, there is one problem that I see so far.

In my experience with MTX amps, they usually like to see a higher input voltage. I am in somewhat the same situation with my 801D. My deck has 4 volt preouts though.

First off, turn the crossover on the amp fully clockwise, this will set the internal crossover at 200Hz and use the crossover setting on the deck. You may have the crossover set real low right now on the amp.

Second, as stated before, get the gains set right.

Third, you may want to add a line driver to the system to get the input voltage to the amp a little higher. If you do this though, buy a high quality line driver. The higher quality line drivers tend to reproduce unwanted noise lesser than cheaper ones.

Fourth, set the Bass EQ on the amp around half way, this will give you a little better bass responce out of that amp.

Let us know whats up after you get all this straightened out.

Chris



-------------
Alpine CDA-9833 HU
Diamond Audio M661 Components
MTX Thunder T6.6 Components:rear fill:
Cadence Q400 4 Channel Mains + rears
Thunder 801D Subs
MTX 1004 10's
Dual 4g wire to rear
4g grounds




Posted By: jdog0411
Date Posted: May 15, 2005 at 2:18 AM

So it looks like optimally I should get a new deck and a DVC sub :-) Man, it seems like I never have the right equipment for what I want to accomplish. Short of getting a deck with higher output pre-outs, where can I find a line driver? I have never heard of them before.

I was reading the manual on my deck, and it does seems there are quite a few sub settings, so I will play around with them tomorrow. I'll get the gain set right and do all of the other things also to see if it makes a difference. I'm considering just getting the DVC version of the sub as an easy way to get a lot more power out of the amp.



-------------
2004 BMW 325ci.
Alpine CDA-9885
JL 300/4 and 250/1
JL XR 5.25 comps
Infinity Kappa Perfect 12





Posted By: racer427
Date Posted: May 15, 2005 at 2:20 AM

Well, try all of the other things stated before blowing more cash on a new sub. You may find that after tinkering with things a bit, that it will power up just fine.

I am off to bed now after 3 am here, ZZZZZZZZZZZZZZZZZZZ tired as hell. Post tomorrow after you do some tinkering.

Chris



-------------
Alpine CDA-9833 HU
Diamond Audio M661 Components
MTX Thunder T6.6 Components:rear fill:
Cadence Q400 4 Channel Mains + rears
Thunder 801D Subs
MTX 1004 10's
Dual 4g wire to rear
4g grounds




Posted By: racer427
Date Posted: May 15, 2005 at 2:23 AM

BTW: I have a Infinity Reference 1230 4 ohm sub that is deceided to hook up today in a sealed box and it pounds like mad. So, don't give up, yes, I have a more powerful amp but, you should be able to get some good results out of the amp that you have.

Chris



-------------
Alpine CDA-9833 HU
Diamond Audio M661 Components
MTX Thunder T6.6 Components:rear fill:
Cadence Q400 4 Channel Mains + rears
Thunder 801D Subs
MTX 1004 10's
Dual 4g wire to rear
4g grounds




Posted By: nismo350z
Date Posted: May 15, 2005 at 10:17 AM
If I'm not mistaken the 12" perfects come with the Variable Q inserts. What insert do you have in the right now?




Posted By: Drewt
Date Posted: May 15, 2005 at 11:48 AM
some of the perfects do. They are the perfect VQ's

Hmmm...isn't the high pass filter on the subwoofer like the subsonic filter. Lets the frequencies above that through without dropping them off??? That may be your probem. Se that to like 15 to 20 Hz...

I had a perfect (a DVC perfect, but a perfect none the less), and it pounded like mad too....too bad I blew it...


-Drew




Posted By: Alpine Guy
Date Posted: May 15, 2005 at 12:03 PM
From what i read in your description of your settings on your deck you have the pre outs set to "rear speakers" which would mean they are crossed over at high pass with the rest of your speakers giving you the responce you are saying you have.  set the rear pre outs to subwoofer, and crossover at 80 hz and see how it goes.

-------------
2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.




Posted By: customsuburb
Date Posted: May 15, 2005 at 12:24 PM
jdog0411 wrote:

racer427 wrote:

First off, you need to get the gains set correctly.

Second, are you using and external crossover or does the headunit have a built in crossover?

Third, what are your pre out's rated at voltage wise?

Chris


Hey Chris, I was hoping you would chime in........I finished the install late tonight, so I didn't have much chance to get the gain set on the amp. i will try to do that properly in the morning. The headunit has a high pass filter setting, that I have set to 125 hz, and it also has a "S/W" setting (which I assume is the low pass filter) that I have set to 80hz. The amp also has a continuously variable crossover. It is not graduated, so I don't know exactly what it is set to. Not sure which of the two I should use, I assume I shouldn't be using both.

According to the head unit manual, the pre-out max voltage output level is 2.2 volts.


You shouldn't have both crossovers in your head unit set at different frequencys. RIght now it sounds like you have a gap between 125 hz and 80 hz. Set both the low pass and high pass on your head unit to 80 hz. If you use the crossovers built into the head unit you should leave the amps crossover on full range or at the highest frequency setting.

Next you need to set the gain correctly. First off definitely don't just leave it at the "factory setting." Since your head unit's pre out voltage is pretty low you will probboly have to have the gain set pretty high. If you have a subwoofer volume control built into your deck, put it near maximum when setting the amp's gain. Do a search for setting gain on here and you will find many posts about it.

Do what Alpine guy said above also... it sounds like the problem.





Posted By: MoneyPit
Date Posted: May 15, 2005 at 12:30 PM

jdog0411 wrote:

There are two settings, "rear speakers" which can be full or subwoofer" and "preout" which can be full or subwoofer. I have the rear speaker setting to full because that channel is my rear door speakers, and the pre-out to subwoofer.

Nope

jdog0411 wrote:

The headunit has a high pass filter setting, that I have set to 125 hz, and it also has a "S/W" setting (which I assume is the low pass filter) that I have set to 80hz.

Would like to find out exactly what the 'S/W' really is. If it's the low pass filter, I would set it up higher, like 150hz or more and let the amp do the filtering.



-------------
Bill
System in progress:
2 Kicker KX400.1's - 945w RMS
2 12" P3's in a ported box built by local shop
1 Kicker KX250.2 to drive the mids and highs
1 set Alpine SPR-136A for mids & highs




Posted By: nitto7
Date Posted: May 15, 2005 at 7:09 PM
hello, I have the save h/u and I was woundering if you might have the  rca to the amp plugged into the wrong pre-out, since there is front, rear and sub.   this might be the reason why there isnt a strong signal going from the head unit...  the one you should be using is the one that has s/w scribed into the metal beside it.  hope it helps.

-------------
Restored '79 Firebird




Posted By: jdog0411
Date Posted: May 15, 2005 at 11:29 PM
Thanks for the suggestion, I have the pre-outs going to the right place on the deck. I messed with the gain and the other amp settings today, and I am getting a lot more output from the sub. It's still not quite as loud and powerful as I had hoped, but I think in order to get that I am going to have to either port the box, or get a 2 ohm sub to get more power from the amp. For a SQ setup, I think it sounds pretty good. There is thump but it is very tight, which is what I wanted from the box. I may consider porting the box to get a little more boom out of it just for fun.

-------------
2004 BMW 325ci.
Alpine CDA-9885
JL 300/4 and 250/1
JL XR 5.25 comps
Infinity Kappa Perfect 12





Posted By: dwarren
Date Posted: May 16, 2005 at 2:05 AM
You will need to build another box for a ported application. It would not be wise to simply port the existing box as the internal volume requirments based on a ported box will be different. It will more than likely require a larger enclosure. Save the sealed box!

-------------




Posted By: Hornshockey
Date Posted: May 16, 2005 at 5:00 PM
if you're worried about not having enough power; wouldn't the ported box be a rather unwise choice due to the lower efficiency of ported boxes?  Am I mistaken? don't ported boxes generally require more power than sealed?

-------------
Life moves pretty fast; if you don't stop and look around once in a while; you could miss it.




Posted By: Ravendarat
Date Posted: May 16, 2005 at 5:03 PM
Nope ported boxes are generally more efficent and are a better choice for someone who is underpowering a driver

-------------
double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer




Posted By: Hornshockey
Date Posted: May 16, 2005 at 5:39 PM
I stand corrected; thanks for straightening me out

-------------
Life moves pretty fast; if you don't stop and look around once in a while; you could miss it.




Posted By: jdog0411
Date Posted: May 16, 2005 at 6:19 PM

Yes, the sealed enclosure gives tighter, cleaner bass than ported, but I know I'm not feeding the sub enough power. I got the 421 amp mainly due to budget constraints, and I wanted to go sealed because of SQ. I think I am going to try putting it in a ported box just to see which I prefer.

I will definitely save the sealed enclosure, I spent a lot of time building it and it is perfect. It's carpeted, glued and screwed 3/4" MDF with silicon sealed insides and a high end gold plated banana plug speaker wire cup in the rear. I'm proud of it, especially since it is my first enclosure. I'm sure I couldn't buy the same quality in a store. At some point in the future I will get a more powerful amp for the sub and try the sealed enclosure again. I also will get a new head unit at some point with higher voltage pre-outs.

I'll keep everyone posted on my progress. I know I have a sub capable of some serious bass, I just need to keep tweaking things until I find the right combination of box, amp and head unit settings. The whole thing is a learning experience for me anyway. I just hope it doesn't get to be an expensive learning experience.



-------------
2004 BMW 325ci.
Alpine CDA-9885
JL 300/4 and 250/1
JL XR 5.25 comps
Infinity Kappa Perfect 12





Posted By: jdog0411
Date Posted: May 17, 2005 at 1:00 PM

Hey guys,

sorry for the shameless sales promotion here, but I have decided that I want to get a bigger amp to power this thing. I need something that will do at least 350 watts rms at 4 ohms. I am going to sell the MTX 421. The amp is awesome, just not enough power for my particular sub. For anyone with a 2 ohm sub, this thing will pack over 420 watts RMS. If anyone is interested in buying it, it is 3 days old, perfect absolute brand new condition and it was purchased from an MTX authorized dealer (sounddomain). I got it for $171.90 shipped. If anyone is interested, let me know, I'll take any reasonable offer to unload it. jrussell38@kc.rr.com.



-------------
2004 BMW 325ci.
Alpine CDA-9885
JL 300/4 and 250/1
JL XR 5.25 comps
Infinity Kappa Perfect 12






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