Hi Guys,
I'm new to this forum and very intrigued about the information given out here.
I want to build a battery-powered portable boombox to take on camping trips. My buddies and I always buy a new boombox every year worth $30-35 and end up trashing it so I want to build something rugged and easy to clean with something as simple as an airduster.
I've come upon this instructable: Ammo Box Speakers
So far, I've decided to run off either D or C batteries with either a T2024 or T2020 Amp (Amazon.com: Lepai Tripath TA2020 Class-T Hi-Fi Audio Amplifier: Electronics) Any insight on the above please feel free to let me know.
I just need some EFFICIENT (will be running off 15-20 watts) 4" full range speakers to throw in. I'm looking at something that will cost around $40 for the pair since these will be thrown around. It's probably not the best budget but it makes sense for what its going to go through.
I'm new to this forum and very intrigued about the information given out here.
I want to build a battery-powered portable boombox to take on camping trips. My buddies and I always buy a new boombox every year worth $30-35 and end up trashing it so I want to build something rugged and easy to clean with something as simple as an airduster.
I've come upon this instructable: Ammo Box Speakers
So far, I've decided to run off either D or C batteries with either a T2024 or T2020 Amp (Amazon.com: Lepai Tripath TA2020 Class-T Hi-Fi Audio Amplifier: Electronics) Any insight on the above please feel free to let me know.
I just need some EFFICIENT (will be running off 15-20 watts) 4" full range speakers to throw in. I'm looking at something that will cost around $40 for the pair since these will be thrown around. It's probably not the best budget but it makes sense for what its going to go through.
Hi,
You can use car speakers but always plan on adding l-pad resistors to the tweeter.
8 ohm drivers are less efficient but draw less battery current, also efficiency
determines how much bass extension you get for box size, its all a balance.
Speaker Stuff the Vifa coaxial here fits your
budget, has a decent suggested c/o, and some good design details. It
will limit the power output of amps designed for 4 ohms, but you get
that back in battery life.
The Lepai IMO is a good choice.
Its all a question of balance, how big, how long, how loud, how deep etc.
But for quality IMHO with its c/o you'd be hard pushed to beat the Vifa.
Here quality means you'll most likely compromise long battery life with loud.
rgds, sreten.
You can use car speakers but always plan on adding l-pad resistors to the tweeter.
8 ohm drivers are less efficient but draw less battery current, also efficiency
determines how much bass extension you get for box size, its all a balance.
Speaker Stuff the Vifa coaxial here fits your
budget, has a decent suggested c/o, and some good design details. It
will limit the power output of amps designed for 4 ohms, but you get
that back in battery life.
The Lepai IMO is a good choice.
Its all a question of balance, how big, how long, how loud, how deep etc.
But for quality IMHO with its c/o you'd be hard pushed to beat the Vifa.
Here quality means you'll most likely compromise long battery life with loud.
rgds, sreten.
Nice! The Vifa Coaxial seems like what I need.
Coming from a $35 boombox, quality-wise anything would be better. I'm going for long-battery life.
The reason why I was looking at car audio speakers is because they are more built to take a beating than let's say speakers built for a home use
The spot we go camping at is pretty dusty...
Coming from a $35 boombox, quality-wise anything would be better. I'm going for long-battery life.
The reason why I was looking at car audio speakers is because they are more built to take a beating than let's say speakers built for a home use
The spot we go camping at is pretty dusty...
I must stress those VIFAs are not center dust protected. There's no screen to avoid dust getting directly into the VC so grill and heavy duty speaker cloth must be used if you intent on using them for a portable speaker. Otherwise they're good except they have terrible sensitivity compared to the Monacor SP-60/4s which are roughly the same price btw.
That much is obvious.
Let's take a typical amp used in a boombox, a TA2020 based one. Max output @ 8 ohms = 8W and 16W @ 4 ohms.
Now the peak volume (per channel) of the 2 drivers is:
VIFA = 96 dB
MONACOR = 102 dB
So the Monacor can play twice as loud although at twice the power consumed but that's still miniscule, ie. about 2W per channel.
Hi,
No its not and the above is wrong. The two drivers are the same efficiency.
The Monacor will only do 99dB, not 102dB (that needs 32W into 4 ohms).
rgds, sreten.
lol. You can't be serious.
Ok. Let me spell it out so even you can understand it.
For the Monacor SP-60/4
90 dB @ 1W
93 dB @ 2W
96 dB @ 4W
99 dB @ 8W
102 dB @ 16W
For the VIFA coax
87 @ 1W
90 @ 2W
93 @ 4W
96 @ 8W
Hi,
Of course I'm serious, the above attitude is childish IMO.
What is the difference between sensitivity and efficiency ?
The Monacors senstivity is incorrectly given, as usual as 90dB/W.
What it really means is 90dB for 2.83V *, for a 4ohm driver this
means its actually 87dB/W efficiency, as nominally 2.83V is 2W.
Happens all the time with people misunderstanding 4ohm sensitivity.
Sensitivity and efficiency are "equivalent" for an 8 ohm driver,
its OK to use /W instead of 2.83V. For a 4 ohm driver they are
not but the misleading practice persists, its a better number.
For sensitivity you have to understand a 4ohm W is actually 2W.
For a 16 ohm driver sensitivity is 3dB less than efficiency,
for a 4 ohm driver its 3dB more, for a 2 ohm driver +6dB.
rgds, sreten.
* Senstivity is always measured with a voltage that = 1W for 8R at 1m.
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No, it's not incorrectly given
Both the 4 ohm and 8 ohm version has a 90 dB/w/m specification. As with all serious manufacturers of speakers, sensitivity is measured at 1W into the actual impedance of the driver.
So the 4 ohms version would actually be 93 dB/2.83V/m.
It is your assumption that the specification is incorrect that is wrong.
Hi,
No its not, ever. Its for 2.83Vrms at 1m into 2pi (halfspace loading).
Sensitivity always relates to the level for a given voltage input,
and so do all the response graphs, no other way of doing it.
Your making up stuff to defend an untenable position,
and ignoring the way it actually is, for no real purpose.
Here is an honest spec :
Dayton Audio DCS205-4 8" Classic Subwoofer 4 Ohm 295-200
As its a 4 ohm driver that is 87dB per 2W not 1W.
rgds, sreten.
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Are you an idiot? Or just trying hard to be. Have you ever worked in the industry at all? Doubtful to say the least.
Here's a trustworthy specification sheet. Not the Dayton crap you posted.
http://www.eminence.com/pdf/Beta_10A.pdf
See note ***. Every respectable manufacturer lists sensitivity like that, ie. 1W into the nominal impendance, or specifies 2.83V for voltage sensitivity but that gives a distorted picture when you manufacture the same driver with different impendances.
Fact is, The Monacor SP-60/8 - the 8 ohms version specifies 90dB/W/m, and so does the 4 ohms version. That's because both drivers are identical except for the impedance, even an idiot will realize this. The magnet strength is the same, the cone weight is the same, and therefore they both output the same at 1W power input.
Now stop you mindless ranting and realize that you made a mistake (you don't even have to admit, I really don't care either way) and be done with it.
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Hi,
No. You seem to be and doing it very easily.
If you don't know what I'm talking about, you don't know much.
Referencing professional driver specs is irrelevant for hifi driver specs,
its different and I do know about it, but here it is not relevant.
I know my stuff, I know what I'm talking about, and what I've said is very reasonable.
You can't see the monacor specs are totally inconsistent, and therefore
not to be trusted in the first place, no way will a 4 and 8 ohm version
of the same driver have the same specs, they simply don't.
You can't base any argument on stupid incorrect published numbers.
I'm fed up with being insulted by the clueless, your saying the wrong things.
rgds, sreten.
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Sadly you don't. You see. I have had about 20 of these Monacors past my test bench, and they measure as I describe above. Naturally not as linear as Monacor's own specs but pretty near. Slightly higher average sensitivity than Monacors measurements. They average 90dB at 2V (not 2.83V). And that is that. End of story. Goodbye.
If it is listed as 1 watt into then it is 1 watt no matter what the impedance is as it is 1 watt into that load.
If it is 2.83 volts then that equates to 1 watt into 8 ohms, 2 watts into 4 ohms, 0.5 watts into 16 ohms, 4 watts into 2 ohms, etc...
It depends on how the spec is written, then that determines how it was tested and at what distance to measure dB level for sensitivity.
If it is 2.83 volts then that equates to 1 watt into 8 ohms, 2 watts into 4 ohms, 0.5 watts into 16 ohms, 4 watts into 2 ohms, etc...
It depends on how the spec is written, then that determines how it was tested and at what distance to measure dB level for sensitivity.
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