Best way to improve my current subwoofers/boxes/amplifier setup

[cannonwillow 10+ year member]

I currently running a monoblock autotek m2500.1D amp rated at 1250 watts rms running at 1 ohm. This is in a 94 ford e150 conversion van with a raised roof and with no middle seats.

I have 2 well sealed boxes behind the rear seat firing upwards. 1 box has a 15 inch mtx thunder 8500 subwoofer with 4 ohm DVC's rated for 600 watts rms. The box has a volume of 2.539 of cubic feet. Recommended by MTX is 2.00 volume for sealed box and a volume of 2.48 for a vented enclosure. The other box has 2 kenwood 12 inch subs in a dual box. The 12 inch subs and box were bought as a unit. Dont have the particlar stats for these 12 inch subs ATM. I think I wil have to pull one of them out of the box to find the subs model number. But they do have 4 ohm SVC's. The boxes are anchored to the floor and each other.

I am running the 2 12's and DVC 15 all in parallel resulting with 1 ohm load on the amp. This should be sending just over 600 watts rms to the 15 inch and just over 300 watts rms to each 12 inch sub. Have 2nd battery under the rear seat ran with 2 gauge wire from front battery. Also using a 2 farad cap and very short lengths of 8 gauge wire for the amps power and ground.

The bass hits hard and sounds good to me but am always looking for improvements. Especially low cost ones.

I can reduce the size of the 15 inch subs box to get it down to 2.00 cubic feet easily. Or I could vent it since it is just slightly larger than the recommended vented enclosure size already. Would it be wrong to mix both vented and sealed boxes. I have a very large amount of open cabin volume in the van. Would I be better off getting another amp so both boxes can be independently adjusted.

thanks in advance for any advice all. My first post here...

Click to read more...

 

[Bettr n' Revrse 5,000+ posts]

None of that lol

 

[THATpurpleKUSH 5,000+ posts]

Sell the 12s and put the 15 in a properly made ported box. Might as well sell the amp too and use the $ from that and the 12s to buy a better amp.

 

[Bettr n' Revrse 5,000+ posts]

Sell the 12s and put the 15 in a properly made ported box. Might as well sell the amp too and use the $ from that and the 12s to buy a better amp.

Guess thats about the best thing to do...

 

[cannonwillow 10+ year member]

Not only am I a newbie, I am also an oldie...

Classic rock is what I mainly like. Such as Rush, Boston, Dire Straits, April Wine, Etc. I do not care for music with continuous deep bass tones. Just not my style. I like hard hitting, crisp & quick deep bass. Chest pound as opposed to ear wax removal.

I have had the subs and sealed boxes for them for around 10 years now. The cheap monoblock was a recent addition that is still better than my very uneducated sub systems from back then, even with the incoming missle like sounds heard at lower volumes produced by the above mentioned cheap amp. I actually returned the first one I bought because of this noise, I was quickly sent a replacement. I still had the frequency shifting non input, amplifier produced, noise. Manufacture replyed to my emails saying this is inherit in class D amplifiers as compared to class A/B amps. I will get to this a little later. I cannot ever except inexpensive as an excuse for poor quality.

TL, but read on anyways. Subwoofer/amp manuals did not help in avoiding easily explained pitfalls . I am now just starting to learn. Years ago I had to learn what not to do by doing it the worst possible way first. Eventually I found the least bad of all really bad configurations. LOL.

Let me mention the first very horrible subwoofer configuration way back then. I powered the 3 subwoofers (one 15 inch MTX with 4 ohm dvcs in one sealed box, two 12 inch kenwoods with 4 ohm svcs in a dual sealed box) with 4 amplifiers!!!! All the amps were Power Acoustiks LT920/2 (560 watts rms at 4ohms bridged or 220 watts rms at 4 ohms x 2 channels). I ran each amp, bridged, to every subwoofer voice coil. 1 amp for each of the 15 inch subwoofer voice coils and 1 amp for each of the 12 inch subs in their own dual sealed box. I thought that the MTX 15 inch rms watts rating of 600 was for each voice coil (600 for one, 600 for the other). Opps..

I did connect the mono subwoofer outputs from the HU to the amps.

I was lucky not to destroy the 15 inch sub, not only because of massive overpowering, but of course sending different signals to dvc's. After a fair amount of research I changed the wiring of the dvc's to bridged in series using just one amplifier. Under powered at 220 watt rms per coil, but at least the sub somehow survived my initial error. I then discovered that the kenwood 12's in common box had a whole lot more thump when powering only one of them. So I switched to just 1 amp for both of them just like with the 15 inch mtx. 1 dvc subwoofer with different signals to each coil has to be worse than 2 svc subwoofers that receive different signals in a common box. At least the coils were not attached to the same speaker in the second case. But using just 1 amp for the 2 12's had way less sound volume than even before. I finally figured out that the 12's were also out of phase. Wiring inside the box had a terminal to one of the speakers reversed. Much better bass after all this and now I had 2 extra amplifiers.

I thought that 4 voice coils of the 3 subwoofers having the same signal even if in seperate sealed boxes would be better yet. 1 ohm stable amp allows me to run all of them parallel. I dont think any one coil is draining away more power from another, as compared to 1 amp to the 15 and 1 amp to the 2 12's. Hits harder for sure. Not mixing different speaker vc resistances at least...

I now use the 4 power acoustik amps for 10 4-way pioneer 6x9 speakers ( 4 in front and below the rear seat in an upward angled compartmentalized box, and 3 on each side up in the raised roof area of the van). And 6 cheap 5x7 boss hole fillers. I never used any of the vans 6 factory speaker locations until just recently. I run 2 speakers in parallel to each of the 8 available channels now. The pioneer speakers are of the same age as the subs ~ 10 years old. One of the power acoustick amps was replaced early on, under warrantry. Yet to blow a speaker. I think pioneers can easily handle more power than advertised. Why is 80 watts contiinuous always the max (or 40), for their 6x9's. Do they really design every model for these specific numbers.

I also have a cheap lightning audio amp from way back then. I use it to power 2 MTX thunder8000 tweeters purchased at the same time as the 15 inch thunder8500 subwoofer. I like my high notes.

Mods feel free to move due to self induced derailment..........................

 

[cannonwillow 10+ year member]

My actual thoughts on improving my sub system on a budget is this. 1st) replace the 135 amp alternator with a 250 amp alternator. 2nd) add a 2 gauge or better cable between the alternator and front battery. 3rd) add a 3rd battery under rear seat. 4th) another 2 farad cap. 5th) Yuk, add a 2nd identicle 1250 watt rms 1 ohm stable amp. 6th) a 18 inch reaudio with 2 ohm dvc's. 1500 watt rms rating. In a sealed box behind the drivers seat firing to the back. can also act as an extra seat. Remember I have no middle seats in the van. Yes, I have a bad habit of combining low quality and high quality stuff. Thats OK I like looking forward to future improvements or at the very least additions.

 

[RangerDangerV2 5,000+ posts]

start over bro... Run the big three, throw away the cap, invest in a good battery up front, and a quality one in the rear. If you are sq minded two sa-8's in a sealed box are probably your best bet. Have somebody like Pro-Rabbit build you a box or get someone to design it for you. Also, if you can find a good deal on deadner you should probably invest in that too.

 

[Joseph7195 10+ year member]

Welcome to the forum! I see you're an old school audiophile that's torn between the old and new. I was that way to an extent also, so i can relate to you in a couple different ways. i used to do the sound for some bands I used to manage, and I had a old RV type van (it used to be modified for wheel chairs, etc) but I removed the middle row of seats and had a sound system in it for when we were on the road. Lot's of room to work with and also a lot of room nobody ever wants to "not" use. I mean, I had 6x9's everywhere and lights, and even a loaded stage sub enclosure (for bass reinforcement on stage) loaded in there too. But I did it all for the Stripper pole i installed where the middle seats used to be. Talk about some stories! But now that I look back, I didn't need all that stuff. I guess I was just trying to shove as much stuff in there as I could. Oh well, I grow and learn

I think you could have a very cool conversion van. But you need to hook us up with some details so other members can help you out. Is this just a cruisin van? daily driver?

What are your goals with your system? Will you be adding video fro passengers? Do you have to stick with the equipment you have, or can you upgrade to other equipment if the new equipment will fit your goals a lot better than the old stuff?

You have a lot going, but you could have a lot better sound and staging and bass if you decide to go with less, but take longer for the install and plan more. I hope that made sense, lol

 

[Bettr n' Revrse 5,000+ posts]

Yep ^^^

 

[mast240 10+ year member]

I'm going to agree with what is being said so far here... less really is more sometimes...

Also, please read this thread, as many of the frequent nooby questions are answered already...

http://www.caraudio.com/forums/general-discussion/532425-new-car-audio-read-first.html

 

[cannonwillow 10+ year member]

Welcome to the forum! I see you're an old school audiophile that's torn between the old and new. I was that way to an extent also, so i can relate to you in a couple different ways. i used to do the sound for some bands I used to manage, and I had a old RV type van (it used to be modified for wheel chairs, etc) but I removed the middle row of seats and had a sound system in it for when we were on the road. Lot's of room to work with and also a lot of room nobody ever wants to "not" use. I mean, I had 6x9's everywhere and lights, and even a loaded stage sub enclosure (for bass reinforcement on stage) loaded in there too. But I did it all for the Stripper pole i installed where the middle seats used to be. Talk about some stories! But now that I look back, I didn't need all that stuff. I guess I was just trying to shove as much stuff in there as I could. Oh well, I grow and learn
I think you could have a very cool conversion van. But you need to hook us up with some details so other members can help you out. Is this just a cruisin van? daily driver?

What are your goals with your system? Will you be adding video fro passengers? Do you have to stick with the equipment you have, or can you upgrade to other equipment if the new equipment will fit your goals a lot better than the old stuff?

You have a lot going, but you could have a lot better sound and staging and bass if you decide to go with less, but take longer for the install and plan more. I hope that made sense, lol

Spot on, Spot on. Old school plus anything New that can fit me. Yes its a daily driver. God awful staging while driving, but its another thing riding in the back.

I actually bought this van a couple of years ago. It was pretty much a seamless transfer of aminitys from an 88 ford van on its last leg. The 88 didnt have the raised roof though. that's the reason for speaker boxes below and infront of the rear bench seat. The raised roof, no middle seats, 135 amp instead of 85 amp alternator, were the main differences. It did still have 6 factory useless 5x7's like the 88.

Video for the rear passengers. 19 inch insignia LED TV. I wanted this particlar one because of the minimal amount of framing around the edge of the screen compared to others and low cost...

Do you know how hard it is to reduce noise when using a PWM sine wave inverter (I use a Tripp Lite 1000w, no fan runs at low load levels). It was everything to keep the extension cord from the TV/ DVD player (Could not find blueray player that was 11 inches across or less, anywhere) and omnipositional amplified antenea above the front area of the van away from RCA cables. Under the rear bench seat and yet above the 4 6x9's is the following (left to right). 4 ac outlets, Using keystone jacks across...AUX input to HU. RCA outputs from TV. then aux rear cig lighter with light taken from the rear of the 88 van (might make since). Then computer vga video, hdmi, and mini audio jack (Inputs to the TV). Then composite rca jacks video/left audio/right audio(Inputs to TV also). Stupid mini headphone jacks auto mute when plugged into the TV even when the other end is not connected to anything. stupid as can be.

I had to drop the chasis ground from the inverter to get rid of most of the static noise. I made sure all AC components chasis did not contact the vehicle's ground. I use 2 prong adapters on anthing that has 3 going to the inverter. Safety first.

Laptop and external harddrive attached to the inverter, play a movie off the computer attached to rear HDMI keystone jack which in turn attaches to a 25 ft HDMI cable running to the TV, aux audio output RCAs of TV running 25 feet back to under rear seat, this then can be run this another 25 feet to the head unit. 75 feet from computer to HU, another 25 feet of rcas to amplifiers in the rear and another 25 feet of speaker wire to reach front speakers. 125 feet (plus 5 foot HDMI computer to HDMI cable) ran back in forth basically 25 feet at a time, mixing ac/dc components, with engine running, is a very difficult noise reduction hobby......

My other hobby is rattle prevention, tell you what this is much tougher with cold winter days (rubber may as well be sheet metal). getting rid of the rattles in the winter makes it tough to open anything in the summer.

I know you know that my HU has no aux mini jack (seems like cheating to me) I only have aux RCA input on the rear of the HU. I should just use a 3 source aux HU input selector under the dash somewhere. 1 input from under the rear seat, 1 that is a mini jack at the dash, and 1 that comes directly from the audio output of the TV. Would cut down on the lengths of RCA cable needed running to the aux input of the HU.

I do miss the days of a HU with optional remote CD changer, let alone dolby c and s noise reduction systems.//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

Search for cannonwillow on youtube, oldschool video from 91, "got too have room for the Speakers". 76 monza, not so much because of the audio system, but...

Mods its time to move this, not just about subs anymore. sorry about the derailment. Maybe I should change the title ...

I never really looked for advice until just recently. I really do like rewiring the system over and over, not sarcastic at all here. I ran the remote-on from Hu to a relay, for 7 toggle switches above the front seats. 1 master on, and 1 for each of the 6 amplifiers. Great for testing/tuning and to have different listening option.

I have always thought the caps may have been ruining the batteries (seems like they start to lose their reserve capacity). Could this be true, I have never even looked into this.

 

[cannonwillow 10+ year member]

bumb. Thx Mast, not really new, but did find the info on how to set the gains with a DMM especially useful in that link. I didn't know capacitors were that useless also.

 

[cannonwillow 10+ year member]

I eliminated all the static from AC/TV to DC vehicle sound by moving the headphone output jack of the TV just a little bit further away from it (Instead of barely not plugged in). This TV senses when a headphone jack is plugged in and mutes all other outputs from it including its own speakers. I cracked my windshield after adjusting the monoblock amp with a DMM. I was told by local police not to play the vans stereo within city limits.

 

[cannonwillow 10+ year member]

:wow:Bettr really dosent have a clue. Some live in a cave when it comes to true sound quality. Some people think that Alpine HU's dont ****