I understood all pretty comfortably till my last post. Is it too much to ask if you draw me an image how to add those resistors to my overall crossover. How big estimated diffefence does this impedance matching have on overall sound. Afterall it's a ghettoblaster and I'm not asking for hifi quality, just adequate output 
(I do more critical listening with my Genelec setup) When shopping for xo components do I need to know something more than the max power passing through the crossover? Thanks in advance!
(I do more critical listening with my Genelec setup) When shopping for xo components do I need to know something more than the max power passing through the crossover? Thanks in advance!
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You just take 3 and 4 resistors respectively, put them up next to eachother and twist the leads together. Don't think I need to make a drawing of that.
It also means you just need to order 14 resistors of the same type in total which is most of the time a lot cheaper than ordering 2 of 3 different types.
2 Watt metal films or 3 Watt carbon film resistors should be good enough for the job. Or actually complete overkill in terms of quality. However, I don't see the point in trying to save 2-3 euros on a speaker set that is already costing over 100 euros if it could affect sound quality in any way, even if it is "just a boombox".
It also means you just need to order 14 resistors of the same type in total which is most of the time a lot cheaper than ordering 2 of 3 different types.
2 Watt metal films or 3 Watt carbon film resistors should be good enough for the job. Or actually complete overkill in terms of quality. However, I don't see the point in trying to save 2-3 euros on a speaker set that is already costing over 100 euros if it could affect sound quality in any way, even if it is "just a boombox".
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Heh I read all your advice again and again. I have a limited brain since I can't understand where to put these 14 resistors? I came up with only 7 resistors from your advice.
This is what I get, is it what you meant?
This is what I get, is it what you meant?
An externally hosted image should be here but it was not working when we last tested it.
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You'll have a Doh!-moment when I tell you the 14 resistors is for both channels, ie. 7 resistors per side.
Pretty much correct in that drawing except the 3 parallel resistor needs to go between the 4 serial resistors and the tweeter (unless you enjoy the smell of toasted amplifiers).
Also note that you need to scrap your current tweeter filter and make another as if the tweeter was 4 Ohms and didn't need a L-pad at all. Then when that's done just drop in the L-pad in the drawing and you're done.
(This is called help to help yourself in fancy business terms, isn't it? :-D)
Pretty much correct in that drawing except the 3 parallel resistor needs to go between the 4 serial resistors and the tweeter (unless you enjoy the smell of toasted amplifiers).
Also note that you need to scrap your current tweeter filter and make another as if the tweeter was 4 Ohms and didn't need a L-pad at all. Then when that's done just drop in the L-pad in the drawing and you're done.
(This is called help to help yourself in fancy business terms, isn't it? :-D)
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He, thanks! No Doh!-moments for me since I'm doing a mono design with only 1 bass and treble driver. I calculated new l-pad and moved the 3 paraller resistor in correct place. Is the l-pad placed correctly? Do I need to calculate the 2.nd order filter for tweeter again with new 4 ohm value?
I think I'll convert the input signal to mono using this so I dont lose too much information from stereo tracks :
An externally hosted image should be here but it was not working when we last tested it.
I think I'll convert the input signal to mono using this so I dont lose too much information from stereo tracks :
An externally hosted image should be here but it was not working when we last tested it.
You know, I thought the same thing once. And built my 3rd boombox version like that (currently on the 9th version). It just until you try it that you find out just how weird mono sounds on a lot of songs. It is not recommendable by a long shot. And I actual thought you were going to build it like the drawing you posted, and that is stereo. Had I known you were going mono I would have advised against it from the start.
This 4th version of mine will be a compromise on a lot of things. My first blaster was a 6,5" two way stereo and I found out that stereo didn't help that much when listening to it in a radius of 10 meters since the left and right channel were only 50cm from each other. I'm familiar with how songs sound when listened to mono. I have one other mono blaster and a Tivoli Audio Pal.
I'll build this to look like stereo and to look like my 3d renderings. It will have black speaker fabrics over drivers so you can't tell by the look that only one side has actual drivers. Other side has amplifier and battery compartment so it will be balanced weight wise. I made already one which has bass driver only on one side and reflex port on the other side.
I'll build this to look like stereo and to look like my 3d renderings. It will have black speaker fabrics over drivers so you can't tell by the look that only one side has actual drivers. Other side has amplifier and battery compartment so it will be balanced weight wise. I made already one which has bass driver only on one side and reflex port on the other side.
An externally hosted image should be here but it was not working when we last tested it.
Final crossover to start testing with. No stupid mistakes left? ...or would it be too optimistic to find 2-way system that fits as a stereo setup into a 25liter box? And is capable of the spl the 8" mono makes in this box.
I was planning to make the input mono before amplifier by this and use only one channel of the 2x100 tripath. I add speaker connectors from the spare channel to the back wall of blaster so it can power external passive speaker. Might come handy sometimes.
An externally hosted image should be here but it was not working when we last tested it.
I was planning to make the input mono before amplifier by this and use only one channel of the 2x100 tripath. I add speaker connectors from the spare channel to the back wall of blaster so it can power external passive speaker. Might come handy sometimes.
An externally hosted image should be here but it was not working when we last tested it.
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I can always rip off this design, but I think it's cooler to try planning something new:
PodZuma - Speaker Building Project at Parts Express
PodZuma - Speaker Building Project at Parts Express
Btw I tested 8,75" / 1" passive behringer (rated 89db/w) with 15 watts ta2024 amp and indoors it gives more than adequate spl. I'm not sure anymore if this precision and p-audio plan is a lot better spl wise. 3db difference, thats small for me. I know Behringer may be in reality lower than stated 89db/w. I test it again outdoors to hear how it performs. The point here is that when listening at low volumes or at inside, Behringer Truth must sound better. And I'm getting that 2x100w tk2050 so I have more power to use. I'm still not 100% certain on what components to choose. I already have that Behringer so it would be free for me.
Would I get more midbass sensitivity if I change the tuning of Behringer from 50hz -> 70hz? If I can stand bigger enclosure I could also take apart a pair of Behringers and have a stereo setup and +3db sensitivity. Now it would already match the precision devices + paudio combo spl wise. It would be larger BUT stereo and cheap for me since I have extra Behringers without use.
Would I get more midbass sensitivity if I change the tuning of Behringer from 50hz -> 70hz? If I can stand bigger enclosure I could also take apart a pair of Behringers and have a stereo setup and +3db sensitivity. Now it would already match the precision devices + paudio combo spl wise. It would be larger BUT stereo and cheap for me since I have extra Behringers without use.
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Remember 3 dB more is exactly twice as loud.
And no, the podzuma is neither a good design, or even half-way finished design.
Remember that speakers used primarily outdoors have completely different requirements, and therefore must be completely differently designed than speakers used primarily indoors.
I've tried to help you as best I could for now. Any further information, look in my Boominator thread. It is the only source on the internet for good advice on how to design these very special beast that we call ultimate boomboxes.
And no, the podzuma is neither a good design, or even half-way finished design.
Remember that speakers used primarily outdoors have completely different requirements, and therefore must be completely differently designed than speakers used primarily indoors.
I've tried to help you as best I could for now. Any further information, look in my Boominator thread. It is the only source on the internet for good advice on how to design these very special beast that we call ultimate boomboxes.
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Saturnus,
I hate to "correct" you, as you are obviously very knowledgeable, but 3dB is not "twice as loud". It's twice the acoustic energy (which may be what you meant), but as I understand it, it takes a 10dB increase in power to _appear_ to be twice as loud to our ears. A 3dB increase in sound level is only a marginal increase in perceived loudness.
Lyle
I hate to "correct" you, as you are obviously very knowledgeable, but 3dB is not "twice as loud". It's twice the acoustic energy (which may be what you meant), but as I understand it, it takes a 10dB increase in power to _appear_ to be twice as loud to our ears. A 3dB increase in sound level is only a marginal increase in perceived loudness.
Lyle
Well, yes and no. If you increase the output it takes 10 dB to appear twice as loud as it was before. However, a speaker with 3 dB higher sensitivity appears to be able to play twice as loud as one with 3 dB lower sensitivity if they are playing with the same amplifier.
Saturnus: Im really thankful for your great help on this one. I've also read the Boominator thread which was helpful. I was just playing around with the Behringer and my Genelecs also, I used my soundcard to simulate 3db and 6db differences. I also tried mono with one speaker, mono with two speakers and stereo. And all these with 85hz bass roll off set. I should have done these test outdoors but it's winter here...
In my opinion also the 3db is only a slight difference, not worth of 150 euros (which would be the cost) Though the pa speaker parts are lighter in weight which is important for me since I'm doing a compact design. I know it's a waste outdoors to have a enclosure tuned to 50hz but sometimes I use these blasters indoors too.
My final question and I'm ready to choose between pa-speaker and behringers:
Behringers have 18 liters internal volume tuned to 50hz. If i reduce the volume to 12 liters the same reflex port should give 60hz tuning. Do I get a upper bass boost, what do I lose? Because If this slight cabinet size reduction is ok and if it gives more upper bass then I can fit a PAIR of behringers and have a stereo and a bit more sensitivity. (and no cost since I own a pair)
Many thanks, looking forward to start building and posting photos for you!
In my opinion also the 3db is only a slight difference, not worth of 150 euros (which would be the cost) Though the pa speaker parts are lighter in weight which is important for me since I'm doing a compact design. I know it's a waste outdoors to have a enclosure tuned to 50hz but sometimes I use these blasters indoors too.
My final question and I'm ready to choose between pa-speaker and behringers:
Behringers have 18 liters internal volume tuned to 50hz. If i reduce the volume to 12 liters the same reflex port should give 60hz tuning. Do I get a upper bass boost, what do I lose? Because If this slight cabinet size reduction is ok and if it gives more upper bass then I can fit a PAIR of behringers and have a stereo and a bit more sensitivity. (and no cost since I own a pair)
Many thanks, looking forward to start building and posting photos for you!
As a wildcard this look nice: B200 - Visaton 20 cm (8") High-end full-range loudspeaker - EUROPE AUDIO
You were talking about not making overkill before. Smack those Visatons in good horn cabinet and they'll rub the floor with your Genelec's
They are not designed for this and can only handle minimal excursion so without horn loading they'll not have very good bass although I do like your idea of using a high end driver for a boombox
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