Tower Speaker Designs - Can vs Bullet, Al vs Glass

Tower speakers either have cans or bullet shapes and most are made from either aluminum or fiberglass. Does anyone know if there are acoustic advantages to either shape or material?

It seems the driver & amp used will be the biggest factor in good sound back at the handle but I have not been able to find anything that favors one design or material over another.

Short answer, is yes.

Long answer is that I don't remember what that actual reason is (something to do with density and resonance), MDF is better than the above, 7 or 12 layer Baltic Birch is even better.

Anyways, any of the above are fine for boats. Get the right enclouser volume, make sure the enclouser is sealed (air tight) and line the insides with sound deaden material. Uses lots of Dyna-mat type stuff and you will get rid of any ringing in AL and fiberglass.

Shape maters a bit too. You don't want a perfect box shape, it will have a resonance. The bullet shape is good, no real parallel walls in it.

I have heard very good drivers sound like poop in bad boxes and very good boxes make marginal speakers sound pretty good.

I'd say that the speaker/box combo makes more of a difference than the amp. Ya, better amps sound better... but not to the same degree as a really well made box with good speakers in it.

As any good car stereo guy, he'll tell ya it's all in the install. That includes the boxes.

I think you guys are trying to apply good accoustic principles to obtain audiophile sound quality in an environment that it cannot be attained. Not that the listener would'nt like better quality, it's that behind a boat at 22 mph and churned up water beneath you, the high quality sound you pursue at 75 feet is simply not achievable from audiophile reference speakers on the tower.
It all sounds awsome (or at least powerful) when you're motionless in the water about to get up, but as soon as you start moving it largly goes to sh$%t.
I'm not saying that 98% of the Tower systems can't be improved upon, but I don't subscribe to the notion that using only MDF or 7-12 layer Baltic Birch for the enclosure is in the top 3 items to change that will make a notable difference.
In the boat is one thing, behind it is a totally different story.
How about some water proof speakers in your helmet?

or better yet: a tweet and mid firing up at the rider from the board, attached to a waterproof sony discman.....

Duane,
sorry to say but you are wrong, most of us that have high end tower systems here know how to make it work. You can hear the bass from my boat 75-80 feet back. I didn't say feel, but hear...

Some of the many reasons MDF is the only choice for 98% of the installers of audio systems in the USA and world wide are:, machineable, absorbs resin, and glue, easily sandable, predictable results, low cost!

Search for all the other posts on tower systems and you will discover, many of us have had huge arguments about it!

KG

Kevin,
Hold on a minute. Firstly, the question at the top is Does anyone know if there are acoustic advantages to either shape or material?
Yes, I agree that in even a reasonable environment (one that doesn't have any competition or obstruction to/for your clean waves)that the box material is key to producing good sound. Just as the volume and air tightness or port size and shape. MDF is used probably in 99% of boxes. NO Argument.
My only point is that at 75 feet and 22 mph with all the other stuff going on, it is not realistic IMO to put MDF or Baltic Birch on the tower and expect listening room quality.
I respect MonsterTower for making the inquirey as some of his competition is also doing to try and improve on an area of our sport that has not yet been addressed very well. At least by the major accessory makers. I was not overwhelmed by what I heard available on the market and like you decided to build my own.
Like you, I'm pretty stoked on what I did. Nice job!
I'd just like to see the average guy that isn't a DIY'r be able to go to a shop and get some nice looking stuff AND can hear with some clarity while riding.
To date, the only ones that I can say that about are custom made!
For me I knew I was on the right track when a rider behind my rig wanted me to turn it down. No, it wasn't distortion.
For those of us that have put something awsome together, we need to share this with the monstertower,skylon and titans of the world.
Don't be surprised if you start seeing a bunch of larger diameter mid range woofers along with Horn Loaded Compression drivers real soon.
I do like the idea of speakers in the helmet though. I'll build it if someone will buy it!
D out

...valid points, sorry, didn't mean to come off like a snot!

to get to the original question by bill, yes ther is a big difference. Aluminum, while solid, regardless of what I have seen (dampening, poly-fill etc) no one has been able to make them sound "warm", even in the boat at lower volumes. Glass will allow you to get the "warmth", but dampening and stuffing will help signifigantly. I damped and stuffed my latest tower box, and it ROCKS!!! One last feature of the tubes that we have even discussed is the internal volume. Tubes tend to cut the volume to less than the minimum required by the manuf'r to save weight, and dimensions. Giving just a 6" speaker 1/4cuft MORE that the minimum will greatly increase the overall frequency response of the driver, helping to achieve a better overall sound from said driver.

KG

Hey Bill here is your answer it may be a little winded but her you go, the requirements for a good speaker enclosure, for any application, is first that it be rigid and as dense as possible. Any flex in an enclosure will cause the low frequecy and mid-bass response to suffer. As for a cylinder versus a cone shape enclosure , a cylinder will have nore internal air volume for a given equal diameter and length. In the case of marine speakers the tower locations they are mounted in restricts the physical size of the enclosure to a size that is not too obstuctive, making internal enclosure air volume at a premium. Proper enclosure fill and damping will also enhance the sound quality of any enclosure material. Marine applications dictate that a sealed enclosure is best to prevent water and moisture damage to the speakers. MDF is porous material that would require additional sealing to make it worthy of this application if at all. It also has the disadvantage of weight over may of the other materials. Home and autosound favor MDF due to the density of this material and to minimize the bracing normally required for larger speakers systems, but they are not subject to water and moisture. Fiberglass can be a good choice for weight and strength, weight and minumum deflection. A cylinder enclosure is a good choice for this application and will also help minumize baffle refraction when kept in scale with the speaker diameter. For safety and durability, the metal enclosures with brackets professionally welded in place would be the best choice for tower mounted speakers.
Each speaker has its own required parameters to mate with a specific style of enclosure and necessary air volume. A speaker designed to work in vented enclosure will not produce the best quality sound if used in a sealed enclosure. A speaker designed for sealed enclosure will not produce acceptable results and may even be damaged if used in vented enclosure at high volume. A vented enclosure will allow moisture to get inside and will eventually damaged the plated components of the speaker and many times suspension components. The enclosure volume, and even the actual size and shape can contour the speaker output by creating peaks and dips due to improper speaker to enclosure match, the speaker's "Q" will determine this. At times this can be an advantage if a frequency band needs to be brought up that the speaker can not correctly reproduce on its own. Sometimes the enclosure volume can be tailored to gain this frequency area.
A speakers sensitivity rating is what will allow a speaker to play louder for given input power. The power handling may be lower in a high sensitivity speaker due to tight voice coil gaps that have high gauss factors and only allow light gauge wire to be used for the voice coil, in turn lowering the input wattage rating. The up side of this is that less input power from the amplifier will be required to get a reference SPL level of loudness with a high sensitivity speaker.
Power handling can be increased when using high sensitivity speakers by using mulitple (common) speakers to divide the input power. This alos results in a + 3db increase of SPL each time the speakers double. ( 2,4,8 speakers etc.) Impedance can be kept in check by a series / parallel connection of the total speaker sum. Even lower sensitivity speakers can increase in SPL and power handling with multiple speakers. This configuration would make a loud, low distortion, easily driven system.
Low frequency is harder to reproduce in an open enviroment like marine applications because unlike a car or home there are few boundaries for "cabin gain" to happen. Loudness gain in the low frequency spectrum is then largely related to power input and cone size for air movement. Horn load enclosures will help but they can get large. Subwoofers and woofers require very rigid enclosures especially if a sealed design is selected, or else frequency response and SPL can be lost due to enclosure flex.
High frequency horns using compression drivers can be used to deliver a larger pattern in this bandwith, they are a bit costly for the better quality horns. Some versions may not be suitable for marine applications due to diaphragm designs that will be moisture friendly. Most compression drivers are very high sensitivity, low power handling and usually do not have the smoothest frequency response without correction at the crossover network level, but they can get loud with very little input power.
Like everything, using high quality components to start with will make your system far superior and less likely to fail you when you want to use it most. The Bossman

Rio: Did you copy That from a Mag or Internet sight? It just dosen't sound like you. Im still trying to understand what you said! Next time try throwing the words Man or Dude in the middle of your sentence, That way Ill know it you. HA j/k "can I get a deal on some speakers" BTW Did someone answer Monster Towers question? Keven seemd to say it, Fillers and Dampning material seem to even the playing feild. I also Agree with Duane, Trying to hear the differance between Aluminum and Fiberglass and MDF tower speakers, I can't say one sound's better than the other, Rio" had some good points as long as the volume is correct and it's dampned and dosen't flex all things should be equal.

I have found it's no use to blame A material or Shape for the sound of a speaker's Out put. But more how it's crossed over and powerd and wired.

Rio, I should have partied with you in Orlando. That's one of my old stomping grounds. I think you should hook us all up here with some Boss Speakers!

Wow, these are some good inputs. Thanks Rio for expanding on the whole issue.
One thing that is of concern to me is the weight issue. Some other threads have described structural issues especially with the added weight of quality drivers in enough number to make a difference.
Rio mentions the space issue which can be delt with somewhat by using area outside of the tower but you can't get past the added weight.
My personal formula to start with is about 200 sq inches of cone area. Putting sizable magnets on the drivers to achieve this can add up to well over 60 lbs. plus the encolure etc.
My opinion in Tower construction (and I know you guys are the experts) is that a totally rigid attachment to the boat will likely produce stress cracks if the Tower flexes due to this added weight.
I know this is off the path a bit but I thought I would take advantage of the Tower mftr posters' on this thread.

One other thought after re-reading some of this. If Car Audio principles are followed, how many of the "Hi End" installs would you say use ANY enclosures for the speakers other then the subs?
I probably don't get around as much as some of you guys but I don't recall this being part of any installs I've seen/heard described. Can someone please clarify if this is the case?
Finally, I would agree with Kevin if we are in a listening room. I would agree with Grant and Rio's comments on enclosure material though, if the project objective is to provide the rider with music.
D out

Yo Grant, your right Boss has hired a sound engineer to design the ultimate speakers and crossovers designed for our parameters, we have prototypes that will blow you guys away, all products are in production and will be available in the middle of November and as far as weight the 530s and 653s will be weighing in at 23 to 26 pounds a pair compared to others at 70 and with a hell of alot less power to push them.

Bossman

Rio, thanks for the heads up. If people are about ready to throw down some cash now, they should wait to see what you are putting together.
Can you share or tease us with a little something more? Like speaker size and quantity, or clarify your "hell of alot less power" comment?
D out

Hey Guys can you imagine a speaker set up for our application we can, we have spent over ten grand in our design for our application aside from what we have spent in the CC bull crap but that is another subject. We all apply max power to our speakers for the best sound and then turn the gain down if it starts to distort, our three way set up for next year will sound great in the boat and even better at 55 to 75 behind the boat by just turning up the volume, others have tried to copy our three way set up, but the weight and material they use for there speakers are sinking them, we are done using car audio that is meant to be heard at 4 to 6 feet in an enclosed area this is why we all push the power (amps, watts)., so great sound with less power means less $$$
Peace the Bossman

Rio, Thanks for the teaser. This is starting to sound more like what I've been pushing for some time now. Car Audio is not for the Wakeboarder!
I can't wait to see what you've got.
D out