Is it possible to build a box for a car Quadaxial Speaker?

[mbill]

Is it possible to build a box for a car Quadaxial Speaker?

I want to build an inexpensive speaker that I can put on both sides of a television. I use this television in my basement when I am working on the computer and it may get moved around, but usually just sits in the middle of the basement were I can easily look up and see it. I want the sound to be better than the existing 3 inch tin speaker in the television. I am mostly interested in an improvement for when I listen to the music channels. But a little better sound with movies would be nice to. Obviously with the existing setup I have no bass, and poor midrange. I was thinking an automotive speaker that was oval would give me the most compact design, especially if I mounted it so its longest axis is up and down, while still giving me some bass.

The speaker I think is the best choice for this project is the “Pyle PLG71.4 7"x10" Quadaxial Speaker Pair” from Parts Express at $46 a pair.

Standard 7" x 10" size fits OEM locations. Features a poly injected yellow cone, high temperature aluminum voice coil, 120 oz. magnet structure, 2" polymer dome midrange, 1/2" neodymium dome tweeter and a rubber boot magnet cover. Includes crossover (built-in capacitor), grills, wires, and installation hardware. One year manufacturer's warranty. Sold in pairs.

Specifications: Impedance: 4 ohms. Frequency response: 40-22,000 Hz. Power handling: 225 watts RMS/450 watts max per pair. Mounting depth: 3-7/8".
Yellow color poly injected cone
Non-fatiguing butyl rubber surround
High temperature aluminum voice coil
Rubber magnet boot cover
One-year manufacturer's warranty

What I do not understand is how to design a speaker box for this speaker. I think it is usually just thrown in a car rear deck and the trunk is the speaker box. Or maybe it is just stuffed in a door. So is there a “proper” size box for this speaker. If anyone can give me some dimensions or educated guess on volume it would be a big help.

The only other thing to mention is I would drive this speaker with some kind of inexpensive add-on amp yet to be determined. Any suggestions here would be helpful also.

mbill

 

[highfihoney]

For the expense of the speaker & materials to build cabinet,plus your time messing with everything why not just get a set of powered computer speakers,then run them from either the back of the tv or from a headphone out jack,most tv's have a mini jack at the very least.

 

[TLS Guy]

Need Thiel Small parameters for the driver

You can build an enclosure for any speaker. However, to begin you need the Thiel Small parameters for the driver. If the manufacturer does not publish them, than you need to measure them.

 

[annunaki]

Without true Thiele Small parameters for this speaker any enclosure design will be a guess. Response of the speaker will be done by trial and error unless you can measure the parameters yourself. Don't expect much out of the speakers. Pyle bulds a fairly reliable product for cheap but they are not well known for sound quality. I am going to guess a ported application my be in order.

Is it possible to build a box for a car Quadaxial Speaker?

I want to build an inexpensive speaker that I can put on both sides of a television. I use this television in my basement when I am working on the computer and it may get moved around, but usually just sits in the middle of the basement were I can easily look up and see it. I want the sound to be better than the existing 3 inch tin speaker in the television. I am mostly interested in an improvement for when I listen to the music channels. But a little better sound with movies would be nice to. Obviously with the existing setup I have no bass, and poor midrange. I was thinking an automotive speaker that was oval would give me the most compact design, especially if I mounted it so its longest axis is up and down, while still giving me some bass.

The speaker I think is the best choice for this project is the “Pyle PLG71.4 7"x10" Quadaxial Speaker Pair” from Parts Express at $46 a pair.

Standard 7" x 10" size fits OEM locations. Features a poly injected yellow cone, high temperature aluminum voice coil, 120 oz. magnet structure, 2" polymer dome midrange, 1/2" neodymium dome tweeter and a rubber boot magnet cover. Includes crossover (built-in capacitor), grills, wires, and installation hardware. One year manufacturer's warranty. Sold in pairs.

Specifications: Impedance: 4 ohms. Frequency response: 40-22,000 Hz. Power handling: 225 watts RMS/450 watts max per pair. Mounting depth: 3-7/8".
Yellow color poly injected cone
Non-fatiguing butyl rubber surround
High temperature aluminum voice coil
Rubber magnet boot cover
One-year manufacturer's warranty

What I do not understand is how to design a speaker box for this speaker. I think it is usually just thrown in a car rear deck and the trunk is the speaker box. Or maybe it is just stuffed in a door. So is there a “proper” size box for this speaker. If anyone can give me some dimensions or educated guess on volume it would be a big help.

The only other thing to mention is I would drive this speaker with some kind of inexpensive add-on amp yet to be determined. Any suggestions here would be helpful also.

mbill

 

[TLS Guy]

No Thiel Small parameters for PLG71.4

That driver you have selected looks a particularly nasty item. There are no Thiel Small parameters published. Likely because every driver is different. If you must use that driver, I would mount it on a large open baffle. You can not guess the parameters of a driver. Box dimensions and port diameter and length etc, have to be spot on or results are terrible.

Are you really serious about building a set of speakers? If so what is your budget? I hate to discourage individuals from building speakers. It is a great hobby and teaches a lot.

Working up a design is real work. However if you really are serious about embarking on speaker building, I will do my best to guide you. You will need to be competent with a soldering iron and need to be able to read an electronic circuit, as you will have to build the crossovers as part of the project. You should do some selected reading before embarking on the project, and I can make recommendations about that also.

Generally car divers do not make good home speakers. You need much better drivers in the home. Believe it or not the car is a much more forgiving environment, within limits.

 

[mbill]

Need more info on open baffle

“That driver you have selected looks a particularly nasty item. There are no Thiel Small parameters published. Likely because every driver is different. If you must use that driver, I would mount it on a large open baffle. You can not guess the parameters of a driver. Box dimensions and port diameter and length etc, have to be spot on or results are terrible.”

Well like I tried to say in my original post I chose this speaker because it was a cheap full range and seemingly forgiving speaker. I did not want to get caught up in a lot of calculations with box and crossover design. I am talking cheap and dirty here like using a cardboard or PVC tube or any scrap wood I can find. I figured if they sound ok just throwing them in a car they would be ok for me. I do not quit understand what you mean by open baffle though. Could you go into that in a little more detail?

mbill

 

[TLS Guy]

Open baffle

You just take a 3/4 inch thick board, preferably MDF, about 3ftX3ft, the bigger the better, and mount the speaker in the middle of it. Mount the long axis vertically.
Within reason the bigger the board the better the bass response will be, as the board prevents the two sides of the driver canceling each other out.
Both sides of the main cone will radiate, so it would need to be a two or three feet from the wall. Alternatively you could put some sound absorbent material on the wall behind the speakers if they need to be closer to the wall.
That is the only way you can mount a driver without some complex calculations.
As I said, just because this driver works in a car environment, don't expect it to do so in the home, where you will be further from the driver.

 

[TLS Guy]

Shielded Magnets

One thing I forgot to mention. The magnets of those drivers to not have magnetic shields on them. If your TV has a CRT, (it is not LCD or Plasma), then you can not use those drivers in proximity to your TV. If you do the tube will become magnetized and your picture will get increasingly distorted and the colors blurred. If you have a TV with a CRT, and if it is not flat screen LCD or Plasma, then you do, you will have to select drivers deigned for that use, that have shields.
Drivers with shielded magnets, say so in the specs. Obviously no car speakers have magnetic shields.

 

[mbill]

My new deluxe setup

Ok since we have been talking I have upgraded my A/V setup. I am no longer using the 20 year old mono TV. Now I am using a “RF to LCD computer monitor” adapter with a 19 inch LCD monitor, and a $12 pair of powered computer speakers. With this premium upgrade, I now have stereo, a nice step up.

I understand what you are saying about shielded speakers, but that is not a problem anymore. The 3 foot panel to mount speakers on is a problem; I was going for a compact design. I took a look at the linkwitzlab web site and found the Phoenix design for an open baffle example, and I see he got away with much smaller panels.


mbill

 

[TLS Guy]

Saul Linkowitz

This is the basis of Saul Linkowitz's design.

1 - A panel with two 8 inch drivers and a 1 inch dome tweeter. It is an open baffle design and the unit might mount on a speaker stand or hang on two thin ropes from the ceiling to bring the tweeter to ear height or slightly above. The panel should have a distance of at least 2.5 ft (0.75 m) to any adjacent wall.

2 - A woofer with two 12 inch drivers arranged for dipole radiation. The woofer should be positioned at the same distance from the listening place as is the panel, and preferably along the side wall, for optimal summation of sound outputs in the crossover frequency range, and minimal excitation of room modes.

3 - An active crossover/equalizer for three power amplifiers of 50-200 W each. The amplifiers must have identical voltage gains, <0.1% distortion and >20 damping factor.

This requires three amps and an active crossover to compensate for the Bass loss of the open baffle.

Saul Linkowitz is very well known in the audio world and has been one of those trying to get away from box resonance, and go open baffle with a heavily equalized bass compensation. This technique requires drivers with a long and linear throw, high xmax.

You said you wanted it cheap, so that's what I did. With no eq a nine sq.ft. baffle would be the minimum to get any bass. At the end of of it all, you will still have a bad set of speakers.

Why don't you buy these drivers?

http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=295-305

And these tweeters?

http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=275-070

You can make a decent cheap speaker out of these drivers, which from my dead reckoning should be able to be small ported enclosures. A crossover with few parts should be possible. It will be a little more money, but not by much, and the speaker will be a hundred fold better.

Are you interested in moving forward in a sensible fashion, instead of being upset that the laws of physics will not change just for you?

I'm not putting anymore time into this project, unless you are willing to move forward in a sensible fashion.

 

[mbill]

I am set

“You can make a decent cheap speaker out of these drivers, which from my dead reckoning should be able to be small ported enclosures. A crossover with few parts should be possible. It will be a little more money, but not by much, and the speaker will be a hundred fold better.

Are you interested in moving forward in a sensible fashion, instead of being upset that the laws of physics will not change just for you?

I'm not putting anymore time into this project, unless you are willing to move forward in a sensible fashion.”


I can see this project is snowballing out of control. I do not know how to design speakers but I do have an idea of what it takes to do it properly and it is by no means a small task. Even after the selection of drivers there are the calculations of the case dimensions, and building it with proper materials and construction techniques. After that the crossover has to be designed and built. And finally you do not really know it is working until you can make some real measurements which are not a simple task. And let’s face it no human can make it right the first time. I was just looking for a little fun of throwing something together without to much thought or expense and was looking for someone to give me some ballpark figures for a box size with the car speaker. I would say for now this project is on hold. My new setup is working nicely for me. Thank you for al the information you have given me on speaker design, it has given me the keywords to Google for proper speaker design.

mbill

 

[TLS Guy]

Help if you want.

If you want to build an inexpensive two way to meet your requirements, I will guide you through it every step of the way. It will be a lot easier than you think. I have guided people through this before over the Internet.
Best Regards, Mark

 

[highfihoney]

Is this thread even for real?

Anybody remember the guy that Sheep nicknamed the floosher,ventwood or some crap like that,this thread has that kind of flavor to it.

 

[mbill]

As real as a tube amp

“Is this thread even for real?

Anybody remember the guy that Sheep nicknamed the floosher,ventwood or some crap like that,this thread has that kind of flavor to it.”

I don’t know what you are whining about? I took your suggestion and used 2 powered computer speakers.

From hifihoney AKA the floosher
“For the expense of the speaker & materials to build cabinet,plus your time messing with everything why not just get a set of powered computer speakers,then run them from either the back of the tv or from a headphone out jack,most tv's have a mini jack at the very least.”

Of coarse taking advice from a guy who runs tube amps was not to smart of me was it.

mbill