Two subs off one Amp??

I already have the new Wetsounds 10" infinite baffle sub. I am thinking about getting one Alpine TypeR sub for either the bow or passenger compartment (still haven't decided). My question is...how would I run these speakers off one amp. The WS 10" sub is a dual 4ohm coil requiring 225Watts. The TypeR is either dual 4ohm or dual 2ohm, and requires 500Watts.

How would I run these off one amp? If I parallel the voice coils, and run the speakers in series, I have 4 ohms. If I parallel the speakers I have 1 ohm. Will a mono amp struggle with a 1 ohm load. I am sure it will run a lot hotter (increase in current), but is 1 ohm a bad idea?

Amps put out a lot more power into a 1 ohm load. I am looking at the Orion HCCA 2400. I have two other Orion amps and would like to keep the same.

if it were me, i would sell the sub you have now and buy 2 - dual 2ohm subs. run them in series/parallel to get 2 ohms.

otherwise you could run 2 - dual 4ohm subs in parallel/parallel to get 1 ohm and just see how she handles it...if it starts overheating and cutting out then switch the wiring to series/parallel to get a 4 ohm load.

run them to get a 4 ohm MONO final load.

Id get a good amp that puts out its rated power @ 4 ohms. Some amps are rated for 1 ohm or lower but will run hot and tend to loose some sq in the process (not that its that big of a deal on a sub).

Darin-

I wouldn't recommend two different subs off the same amp. Although everything will work as stated above and ohm load will be correct, there are other things to keep in mind. The first thing I looked at was the sensitivity of both speakers. The sensitivity is measured in dBs and tells you how efficient, specificly how loud it will be with a given amount of power.

Alpine Type R sensitivity = 83dB
Wetsounds XS10 sensitivity = 88dB

With this being said, the XS10 (based off specs) will be playing louder with the same amount of power. The difference is only 5dB but in the world of decibels +3dB equals twice as loud.

If you did run a two channel with both woofers connected you would need to adjust the amp to play for the XS10 and the Type R would be left wanting more power and with less output than the XS10. Another option would be to run 2 2chs or a 4ch so each sub would have its own gain control. There are a few amps on the market that are 2chs and have independent gain for left and right chs. If possible try to have separate control of each sub.

I sometimes take audio a little to far because I'm way to spoiled with listening to the best of the best and using them as a reference. If I was going to be taking this to the next step or talking about a vehicle application I would go into the possibilities of cancellation between two different types of woofers and even further cancellation being in two different locations.

What I think it would come down to is putting it in and listening. If you are happy with it, keep it. If you have the option to try a few different things before next season I would and see what works best for you.

I would Recommend, as Ben stated, 2 identical subs. Do not know about the alpine, but the W/S can be wire either 2 or 8 ohm (I would wire it 2 ohm tho) so you would need an amp that is stable at what ever ohm subs you go with. If you haven't heard the W/S yet it is awesome.

As far as amps, make sure, as noted, it's stable at the ohms of the subs you want to run, puts out the correct RMS at the subs stated ohms, and run the subs on separate channels. $.02

also dont run the sub infinite baffle{free air}. BUILD A BOX. i have yet to hear a good sounding free air sub

Is that what they are calling a Sub hanging off of a board these day's a "infinite baffle{free air}" LOL Thats funny. Why don't they call it what its is HALF A$$.

A Baffle is the board that the sub mounts to. Every propper sub box has a baffel. I guess these days a sub box that dosent have a box is being called "infinite baffle" They should be called "infinite box" or "Box-less sub" or "Sub hanging on a board"
LOL

My advice: get 2 matching sub's build 2 real sub boxes.

Subs designed for infinite baffle applications are sometimes the best choice. I run one because I do not want to sacrifice storage, and I do not plan on entering db drags with my boat. It sounds pretty good and there are others that have them installed that will agree infinite baffle can fill the needs of many. What you do not want to do is buy a sub that isn't designed for free air and use it as one. It will be mushy. If anyone wants to hear it, they can come listen anytime. You will agree that it sounds great. Does it sounds as good as a sealed enclosure?....probably not; but you are IN A BOAT with wind, water, possibly pets, exhaust, etc, etc, etc. It's hard for many to justify spending the money involved with making the modifications to a boat to install a sealed enclosure when a free air can possibly drop in, fit the bill, and sound close to as good. My .02: use an infinite baffle if it suits you.

I am sure the typical WW mindset of mo' money means mo' betta' will take over the argument here though.


Also know that "these days" infinite baffle is a grandfather to the sealed enclosure and is more popular than you think. They are also used in a variety of applications outside boating.

I am sure everyone bashing infinite baffle completely understands what a baffle is designed to do in all enclosure types. It is the means to isolate the sound waves on both sides of the driver to prevent phase cancellation. Sub design allows for the sub to interact withthe sealed enclosure to help with frequency response in those applications. You have to pick the right sub for the right design.

(Message edited by OlskoolTige on November 20, 2007)

Not a good idea to run a free air sub and a sealed sub off the same amp. One sub is going to get beat to death.

Im not trying to make a argument for "Mo money means Mo better". Everyone has their opinion on what sounds good. If you dont listen to music thats bass heavy or you dont turn it up that much you could make the argument that Sub's are a waste of space and money and a Sub mounted to a board works just fine. I would agree with you there.
If your Music taste includes any Hip hop or House as soon as crank it up your gonna find out that that sub mounted to a board just dosent cut it.

Who is running a free air and a sealed off the same amp? That is a no-no.

"G", Evidently you have no idea on the mechanics behind a sub designed for infinite baffle application and why/how they work in certain scenarios, so there is no point in even trying to explain. Have you any experience with a sub specifically designed for infinite baffle? What about home theater? Infinite baffle sub != regular sub on a board. You are right in that it isn't going to reproduce very low freqs due to mechanical limitations, but it hardly is going to fit into not meeting the needs af anyone. It is absolutely an option to anyone looking to improve their boating experience. They don't need to go out and buy Zapco amps and sealed enclosures all the time.

I wasn't arware Hip Hop/c-rap fell into a music category?????? Maybe Solja Boy is moving up......

(Message edited by OlskoolTige on November 20, 2007)

Not the author, but just wanted to pass on some info about "free air" subs.

"Speaker installation falls into three or four basic categories:
* Infinite Baffle
* Sealed
* Vented
* Bandpass (due to the nature of the discussion, let's not go into this one)

In general, any woofer has a set of parameters that can be controlled by the design engineer, and these parameters are used and manipulated in the design phase to tweak the woofers performance so it is suitable for a particular application. These parameters can also be used in the enclosure design phase to optimize the enclosure and/or environment that the woofer might be used in. The three critical parameters we have in a woofer are:
Fs: Free-air resonance. The natural resonance of the moving "soft" parts of the woofer, i.e. the cone, the voice coil, the surround roll, and the spider. Fs is expressed in Hz, or cycles per second.
Vas: Volume Acoustic Suspension: Expressed as a volume of air, either in cu.ft. or litres. This parameter tries to define the "stiffness" of the woofer's suspension as an equivalent volume of air confined in a vessel; picture a bicycle tire pump. Hold a finger over the valve, and push down on the cylinder; the resistance you feel is the compliance or springiness of the volume of air in the tire pump. The woofer has a similar springiness...
Qts: The woofer's "Q": Funny number; it has no dimension, no height, no volume of air, no nothing. In general the Q speaks to the "ringiness" if you will of the speaker. A bell for example has a very high Q. It rings and rings and rings.... Sound forever, as it is vibrating at its "Fs" for a long long long time. Grab hold of the bell with one hand and hit it again. "Clunk" Your hand has added a damping component to the resonant system, and it no longer rings. That bell with your hand on it is now "Low-Q"

In very general terms:
Woofers with very low FS values, very low Qts values, and very large Vas values work best in sealed enclosures. The woofer looks to the volume of air trapped inside of the sealed enclosure to provide the necessary spring stiffness to control the motion of the woofer.

Woofers with Fs values of pretty much anything, medium Qts Values, and smallish Vas values work well in vented enclosures. The small Vas and medium Qts values help to control the woofers motion, and the air inside of the enclosure still acts as a spring. Neat thing with a vented box: the springiness of the air inside changes in phase depending on frequency. At optimum tuning, the air moving in and out of the enclosure, is more or less in-phase with the cone of the woofer. I.e. when the cone of the woofer is moving outward, so is the air in the port, and when the cone is moving inwards, the air is doing the same thing. Hard to grasp, but realize this: a properly designed vented enclosure will have HIGHER pressures inside the enclosure when compared to a similar sealed enclosure. It is due to the fact that the air, acting as a spring, has gone through a phase shift and is moving in and out of the enclosure with the woofer, in the same direction at the same time. The sound created at the port is "in-phase" with the sound coming from the woofer, so a vented box will be louder typically, (emphasis on typically, there are exceptions to every rule).

In both sealed and vented woofer systems, we are providing an effective means of preventing the pressure wave from the back of the woofer cone from interacting with and cancelling the pressure wave off of the front of the woofer cone.

An infinite baffle woofer is designed in such a manner that it has a very low Vas value; it does not need the help and/or support of the air trapped inside of an enclosure to control its motion. The control is provided completely and totally by the woofer's suspension; the surround roll and the suspension spider. As Spharis put it, a free-air woofer is inherently stiff; that is to prevent it from just jumping in and out of the woofer's basket. Due to this stiffness, we will see Qts values that are fairly high; this is a result of the stiffness, and while not totally analogous, the infinite baffle woofer will "ring" to an extent like a bell, quite naturally. Not to worry, it really does not affect the sound too terribly much.

I know, blah blah blah, I just wrote a book, but hang on, not quite done. When using an infinite baffle woofer, (or any woofer for that matter) we still have to do the critical job of preventing the pressure wave off of the back of the woofer from mixing with and cancelling the pressure wave off of the front of the woofer. This is done by mounting it in a wall of some sort; it is that simple. In a typical boat install, the woofer is put in the helm toe-wall, and the back of the woofer is inside the storage compartment fore of the helm. Since the storage area door is typically closed, we do not hear the back wave off of the back of the woofer; it stays inside the storage area. Try opening the storage area, and then stand at a point midway between the steering wheel, and the storage hatch, i.e at roughly the windshield. Notice how the bass volume goes down? That is because you are hearing the front wave mixing with the back wave and the two are cancelling each other out. That points to this point: For an infinite baffle woofer, we always want to prevent the sound coming off of the back of the woofer from interfering with the sound off of the front. Everything else as it relates to the woofers performance is totally dependent upon the woofer design, and not the box, the box volume, the vent tuning, blah blah blah.

Put simply, an infinite baffle woofer is one that needs no box to operate properly; just a wall to separate the sounds coming off the opposite sides of the cone."

Hummmmmmmmm. Very instresting. Your data is very compelling. Your theroy's seem very solid and tested with lots of data to back them up. You sound like your realy know your stuff.
I feel like a fool. Everything I thought I knew about woffers and systems in boats turnd out to be totally wrong. My lifes work is all a waste. I dont know where to turn from here?

I had no idea the people a Krako followed these Wakeworld audio thread's and posted in them thanks for your insite.

While I like Kraco, I really think the Radio Shack gear has a significant advantage. I believe everything I read in magazines, specifications are definately more valuable than real world experience.

I too feel quite foolish, I am running a sealed sub off the same amp with a ported sub. I guess I am lucky my boat has not caught on fire.

"G", Mikeski

Just trying to add to meaningful conversation with some info that was given to me by an acquaintance who is an Audio Engineer.

Feel free to disagree, but I do not see a need to be sarcastic with your response about info that you do not agree with.

Mikeski....I doubt you are running the sealed and ported off the same channel (as the above post should read, not same amp).

BTW Spark-o-matic is the brand of choice for me.

Chp....I mentioned there was no point in trying to explain.


(Message edited by OlskoolTige on November 20, 2007)

Steve,

Actually I am running 5 subs off a single channel HiFonics BX1500D. Four of them are ported and one is sealed. This yields an electrical network equivalent of 1.33 ohms. The theoretical acoustic network is a mess, but it works. The network of the four small subs is running out of phase with the single 12, the amp is running about 70 degrees out of phase with the rest of the system. After a fair amount of testing I find these settings to produce the most pleasing sound in most listening positions. It works for now, when something blows I will change it. From a blank sheet design standpoint it's a disaster but in practice it works. Things like this happen when your system "evolves" over the years.

Chpthrl,
Your post (copy and paste) is interesting reading, fundamental and informative, but doesn't really say anything relative or helpful to the topic. It just kind of implies that you know a bit more about subs than Grant??? Grant knows a great deal more about putting boats in subs than he does about spelling and grammar. He has set up lots of heavy hitting systems. He likes to use W7s because he knows how they operate and knows how to set them up so they sound good. We are friends, appreciate each others systems but we differ when it comes to our spending approach.

Boats are open air, fiberglass, strange angles/curves, etc. Sound waves fly in all kinds of directions and are completely unpredictable. The rules of acoustics go over the transom when it comes to boats (I am a EE with a minor in acoustics). When it comes to placing subs in boats there is no substitute for experience.

In my opinion...The easiest way to get good sounding bass in a boat is from a single sealed woofer (preferable in the natural horn formed by the driver foot well). Add another sub and you will have two elements in the phasing argument, add a ported sub and it gets even more complicated. It took me months to get mine somewhat sorted out. I have a pair of tens and another amp sitting on the shelf ready to go when I blow something up.

Some stereos are designed well, some evolve like mine.

I avoided this topic on first view but it's slow at work today so I figured what the heck, throw a little gas on the fire...

Got your turkey yet?

M

M,
I certainly don't want to mislead anyone here. I did state that I did not write that, so I do not believe that it implies that I know more then anyone else here (feel free to run with that one)about stereos. If I did, I would not have asked the question about free air subs in which I received this info.

If anything, you initial response to my post implied that you were anything but a professional with a degree. I'm glad to find out other wise.

Your last post was more like what I would have expected from you, a response containing actual useful info relative to the topic. Thank you.

As far as relevance and helpful...........the subject of free air subs was brought up. It was stated "dont run the sub infinite baffle" with no explanation other than the poster's personal opinion about sound quality. I feel that the info I posted was not opinionated, but was more informative and simply described the differences between the 2 subs.

With info, and not just opinions, a reader can make logical decision on which direction they want to go.

Second-hand, plagiarized general info vs. opinions forged from real world experience specific to the application? (i.e. subs in a boat) I'll take the opinion every time, thanks.

Whoa!!! I sure did miss some stuff since my last post. I think that my recommendation for Darin's (original poster) needs and application would recommend to try putting in the XS10 in a sealed enclosure and see how it sounds. If its not enough add a second XS10 (in the same area if possible) or get a woofer capable of more output.

Sorry if that seems to simple but it will work.

Full proof option just put one of these in with 1 cube of air, sealed, side fire towards hull under drivers dash with a true 1000 clean watts.------------------------------------------------>

Psyclone,
Here, I plagiarized this from Webster's Dictionary

Plagiarize \plaje,riz\ vb -rized: -rizing: use (words or ideas) of another as if your own.

My thoughts on free air subs........First, it's all about the listeners preference. IMHO, boats, due to thier design/construction, resonant base far better then a automobile, so infinite baffle suds work great in boats. BUT

2nd, sub location and space. You need to decide where you want that sub(s). If you want to put it in the drivers bulk head, for example, and dont have a large enough opening to get an enclosure in, then go with a free-air. A free air in the bulk head wall with no box would sound better then a non-free air sub with a box that is too small. If location is not going to be a limiting factor, then go with a standard sub and a proper size enclosure. if you want to put the sub/box in a storage compartment, I would suggest venting that area. cracking the door ajar works great while sitting still, but not always practical when under way. An easy solution is to cut a speaker hole and cover it with a speaker grill. Sometimes some heavy weight cloth over the hole/under the grill will hide the fact that it is a hole.

Darin, other posters and readers,

I apologize for being the cause of this topic becoming de-railed. There are some very knowledgeable people here and a ton of great info. In the end, I know you will find what you need and put together a kick @zz system.

Happy Thanksgiving everyone.