I hope I posted this in the right place... I was trying to build a portable speaker. My budget varies but I didn't want to go crazy. It started out as a simple idea... build a speaker box that I could plug in my Qudelix 5K to have the awesome app and equalizer. I didn't care if it didn't sound "great"... My goals were: 1: Try not to spend more than necessary. 2: Don't make it TOO big, I wanted the biggest speaker to be no more than 4 inches if I could help it. 3: I wanted to separate the highs and lows between two speakers, A tweeter and a woofer/full range, with a crossover. Added: 4: I realized flat 20hz to 20,000hz was NOT going to happen, so I decided I wanted it to have around 60hz to 19,000hz on a relatively decent flat overall response curve, made more difficult as most Woofers I looked at had a bit too much fall-off around 100 to 80hz. BONUS: 5: Use 4ohm speakers for power efficiency.
I tried to learn what I could browsing many forums and actual build guides.
Looking at Ohms I saw things like: "Make sure the speakers are the same Ohms as the Amp or you will blow the speakers or burn out the amp," or "The speakers can be a higher Ohm than the Amp but they have to be the same as the other speaker," or build guides where the speakers' Ohms didn't match at all.
Looking at Wattage I saw things like: "Match the RMS wattage of all the components," or "Make sure the wattages of the speakers are a bit higher than the Amp so the Amp can't blow them," or "If the speakers' wattages are too high compared to the Amp's then they will stress the Amp."
Looking at Sensitivity I saw: "The ohms and wattage don't matter, it's the sensitivity of the speakers that matters, match that instead," but on some build guides I saw, none of that matched either! I saw things like a 20w RMS 4ohm 90dB 2.83V/1m Tweeter being used with a 50w RMS 8ohm 80dB 2.83V/1m Woofer!
I'm incredibly confused! I spent several days looking at Speakers and Amps trying to just match everything so I don't have to worry about any of it, but that being very difficult isn't even what has stopped me... It's my realization that I'm in way over my head! I'm obviously either missing something or overcomplicating it... I just want to know how to match a Tweeter to a Woofer with DECENT accuracy and not blow anything up...
...
Now with how expensive the parts are that match in ways similar to those above, I'm considering doing a mono Amp with only 1 Tweeter and 1 Woofer for now and eventually building a second later splicing them together by feeding each the split left and right signal... or using two Bluetooth transmitters, each with a split left and right signal out of my Qudellix to each of the Satellite speakers.
I tried to learn what I could browsing many forums and actual build guides.
Looking at Ohms I saw things like: "Make sure the speakers are the same Ohms as the Amp or you will blow the speakers or burn out the amp," or "The speakers can be a higher Ohm than the Amp but they have to be the same as the other speaker," or build guides where the speakers' Ohms didn't match at all.
Looking at Wattage I saw things like: "Match the RMS wattage of all the components," or "Make sure the wattages of the speakers are a bit higher than the Amp so the Amp can't blow them," or "If the speakers' wattages are too high compared to the Amp's then they will stress the Amp."
Looking at Sensitivity I saw: "The ohms and wattage don't matter, it's the sensitivity of the speakers that matters, match that instead," but on some build guides I saw, none of that matched either! I saw things like a 20w RMS 4ohm 90dB 2.83V/1m Tweeter being used with a 50w RMS 8ohm 80dB 2.83V/1m Woofer!
I'm incredibly confused! I spent several days looking at Speakers and Amps trying to just match everything so I don't have to worry about any of it, but that being very difficult isn't even what has stopped me... It's my realization that I'm in way over my head! I'm obviously either missing something or overcomplicating it... I just want to know how to match a Tweeter to a Woofer with DECENT accuracy and not blow anything up...
...
Now with how expensive the parts are that match in ways similar to those above, I'm considering doing a mono Amp with only 1 Tweeter and 1 Woofer for now and eventually building a second later splicing them together by feeding each the split left and right signal... or using two Bluetooth transmitters, each with a split left and right signal out of my Qudellix to each of the Satellite speakers.
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I suggest this every time a complete novice asks this kind of questions: if your goal is to build a speaker a be done, then build a design coming from a reputable designer. This design probably fit your requirements: Overnight Sensation
Designing a crossover is not an easy task, and the chance that a novice without knowledge (considering the questions asked), can build a speaker without major flaws at the first build is pretty zero.
Ralf
Designing a crossover is not an easy task, and the chance that a novice without knowledge (considering the questions asked), can build a speaker without major flaws at the first build is pretty zero.
This is an example of a question that shows that you don't know how to read the T/S parameters and the FR graph of a woofer, in other words you aren't able to choose the right driver for the task. The FR for a woofer is usually shown in the case of an infinite baffle, but the bass behavior of a woofer in a real speaker depends entirely on the alignment chosen (closed box, reflex or the likes), something that can be calculated/simulated from the T/S parameters.
Ralf
Thank you for your response! If I've understood you correctly I need to learn about the TS parameters and FR graph more, and what I've gathered so far is that the enclosure of the speaker will affect its response, which immediately makes sense and complicates it a little bit if I want to maximize its performance. But the biggest issue I'm having currently is the relationship of the Ohms and Watts between the Woofer, Tweeter, and Amplifier. I'm fairly sure I know what Watts (power), Ohms (resistance), Amperages (pressure), and Voltages (potential difference) are, and I know what an Amplifier does. Also, I think I've just learned from more research that the crossover point I need to choose is below the point where the various angles diverge on the Woofer's FR graph, and then I need to get a tweeter that can go below that point to "cross over."
But what I dont know is the resilience of the parts and how they affect each other.
Why do I see Tweeters rated at the same watts as the woofer on some setups, and on others it's like 1/3 the rated wattage of the woofer? Is it because that tweeter is 8ohms and the woofer is 4? Is it because Tweeters don't need as high of a Watts rating? and what about the ohms... can I put an 8ohm speaker on a 4ohm Amplifier, or does it need to be the same? Do I need to keep a speaker around the same rated wattage of the Amplifier, or does the speaker need to be a bit more?
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Yes, and therefore I probably dont want my Amplifier to be higher Watts than my Woofer can handle safely. I know the speakers are a "load" much like a motor. But is there an exception for Tweeters? Can a speaker be well beyond the Amplifier's rated wattage? Won't it just be quieter, or will it harm the Amplifier? Also, perhaps I would get a book at some point, I do LOVE messing with electronics. But fine details are beyond me tat this moment.
As counter intuitive as it seems on the surface, you are safer to have a higher powered amp than the rating of the speaker. When push comes to shove, it comes down to self control. If you lose that, the higher powered amp, in its comfort range, will not begin to ‘clip’ like an under powered amp will. Amplifier clipping is far more dangerous to your speakers than a little too much regular power. Please look this up. It is not mysterious. Amplifier clipping. https://en.wikipedia.org/wiki/Clipping_(audio).
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You don't know what is "safe".
The speaker load (impedance) varies with frequency.
Tweeters voice coils are lighter and burn up faster with less power.
Yes.
A speaker does not have to be driven with any more power than is required for the SPL (sound pressure level) desired.
The speaker's rated power won't harm an amplifier.
Amplifiers without adequate protection circuits can overheat and burn up various internal components.
This source will answer far more questions than you have asked:
https://geoffthegreygeek.com/
After you understand some of these basic audio concepts, you can start learning how to design:
https://www.diyaudio.com/community/...igning-crossovers-without-measurement.189847/
You will also find that your #1 goal: "Try not to spend more than necessary" won't be achieved by DIY, it is far less expensive to buy a mass produced item that fits the rest of your goals.
That said, once you understand the basic audio concepts, you can make more informed decisions based on what you decide is necessary.
Cal,
If you lose "self control" (or play a music track that was recorded "louder" than the previous without turning down..), and push the higher powered amp into clipping, it will burn the speaker's voice coil faster than a lower powered clipping amp.
It makes no difference to the speaker if the waveform it receives is clipped or "regular power", too much average power is what causes thermal damage.
An amplifier driven into severe output clipping simply delivers more average power than it would if not clipped.
A higher powered amp will deliver more average power when it clips than a lower power amp.
A higher powered amp also has more peak potential, so can cause mechanical damage that might not occur with a lower power amp.
Art
Art, I will not challenge your years of experience but to say the advice I have given is incorrect, I believe needs to be rethought. I have been suggesting the same thing for 40 years and I have to say this is the first time it has been refuted. Perhaps you are looking beyond what I actually said. A more powerful amp is safer for the drivers than an underpowered amp when driven beyond either of their capabilities, when the person on the large knob is dictating what happens.
Art, we are talking the average Joe, not the stadiums you are dealing with.
Art, we are talking the average Joe, not the stadiums you are dealing with.
Thank you for the link and advice. Though, I feel it's a bit overkill for my otherwise small project... I'm just trying to build a small portable speaker that's like 8 x 8 inches max. Buuuut... I did say I love learning about this kind of stuff... I'll look into it when I have time. And maybe that's for the best as you are right, it would give me a better understanding of what I need.
As for the money goal and DIY expenses: I chose my words very carefully there, I said "more than necessary." IE: not buy a $200 Subwoofer speaker just because it can handle 300 watts and go down to 15hz, or anything like that. Parts will be chosen based on necessity and value. I will get the cheapest part that does what I need it to do and doesn't have some crippling compromise.
This is what I was thinking.
But this makes some sense as well... as long as I don't turn the volume up too high, the speakers should be fine, yes?
HOWEVER... "In the frequency domain, clipping produces strong harmonics in the high-frequency range (as the clipped waveform comes closer to a squarewave). The extra high-frequency weighting of the signal could make tweeter damage more likely than if the signal was not clipped." - https://en.wikipedia.org/wiki/Clipping_(audio).
From the research I have done recently, it is common for the Tweeter to be less rated amps than the Woofer and sometimes even the Amplifier, anyway. As far as I've gathered, and forgive me if I word it incorrectly: the reason is the Tweeter doesn't get most of the power anyway because the Woofer... 'takes' most of the power? 'gets' most of the power because of the lower frequencies? Either way, the tweeter ends up being at or even below the rated Watts of the amp anyway. But the Woofer still is at or above it, so is this 'clipping' still an issue?
Also, from what I can tell no one has still said if Ohms matter. I'm going to do more research using the links and advice provided by you fine people, but for now, I'm going to err on the side of caution and match the Ohms of both to the amp.
That's why I'm asking. And even here there seems to be a bit of disagreement on what is "safe." Perhaps I will have to wait until I look through and research to figure it out myself. An understanding of how the components work should give me an idea... Perhaps it's MY fault for wording my questions the way I did... what I originally wanted was a: "match the Ohms" or "get speakers with higher Ohms" or "the Tweeter can be a lower rated wattage than the Woofer" or even "It depends on the quality of components you get" or even an "It's not that simple, you have to do more detailed research to not blow it up." But perhaps I'm ignorant on even that... perhaps I'm just trying to be lazy... maybe I worded it all wrong... or maybe I'm just misunderstanding.
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The average Joe will not hear clipping distortion.
The average amp can be easily driven into clipping with a source capable of 4 volts like the original poster's Qudelix 5K.
A more powerful amp driven into clipping will heat and burn the drivers faster than an lower powered amp.
Any amp driven within the thermal and mechanical limits of a driver is "safe".
I know you said "if any other seems less appropriate," but I shall interject with this anyway. While I appreciate your enthusiasm for the... classic methods of learning, it's also a complete waste. If I build something that doesn't sound or perform great but at least works, I can still take it apart and try again with a few different parts later and use the others for another project. If I burn something up, that is not only a waste of money, but also electronics/parts and time. And as much as I'd still be willing to employ such learning methods, if I can ask people who have already done so or know how to avoid it what is a good rule of thumb for matching Watts and Ohms of a Speaker to an Amplifier and save myself some initial trouble, then I would appreciate the community for being so helpful. I hope you have a wonderful day!
Rule of thumb: a thumb is ~an inch wide.
The speaker impedance, measured in ohms, should be no lower than the minimum impedance the amplifier is rated for.
The speaker's power rating in watts should be enough to deliver the SPL (sound pressure level) desired at the frequency (measured in cycles per second, Hz) desired. The SPL delivered depends on the sensitivity of the speaker in it's box at any given frequency, which will vary with frequency.
The amplifier should be capable of delivering adequate voltage at the speaker's impedance to achieve the power in watts required for the speaker to deliver the desired SPL.
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Ditto. First build a proven design. Get some of the free simulation tools for box design and crossover design, then learn why the designer of your speaker made the design choices they did. That will introduce you to T/S parameters, boxes and crossovers.
Come on weltersys. You are muddying everything up. Take a breather.
To OP: Listen to Cal Veldon. A small amp will not protect your speakers and your tiny tweeter voicecoils. Welter is smart enough to advocate the opposite, but my god I dont know why he is going there.
Cals advice is an old and very important one which has saved thousands of speakers. It doesn't cover all theoretical events and so what?
If You want to build? Build well documented speaker from plans.
Cheers!
To OP: Listen to Cal Veldon. A small amp will not protect your speakers and your tiny tweeter voicecoils. Welter is smart enough to advocate the opposite, but my god I dont know why he is going there.
Cals advice is an old and very important one which has saved thousands of speakers. It doesn't cover all theoretical events and so what?
If You want to build? Build well documented speaker from plans.
Cheers!
I have my own rule of thumb to not destroying a loudspeaker. I stick to being conservative
in any conceivable way. Any loudspeaker electrical power rating I reduce tenfold.
Since they explicitly say there is no warranty for fried or mechanically damaged parts,
the only thing it will save your property is your common sense.
in any conceivable way. Any loudspeaker electrical power rating I reduce tenfold.
Since they explicitly say there is no warranty for fried or mechanically damaged parts,
the only thing it will save your property is your common sense.
About 60Hz is a good response for a 5" midwoofer but I'm not sure you get there easily with a 4".
Something like the FaitalPro 5Fe120 gets there easily with decent sensitivity. Being officially a pro driver the cone is weather resistant which might make a difference for a portable speaker. It works fine out of a roughly 4.5L sealed box and is quite cheap too (£24ea).
WOW that thing is kinda awesome... but also wow, that thing is rated at 80 watts... I don't think that would do well with the 16w amplifier I chose... or maybe it would, heck I still don't know despite that being a main question. But it seems Cal has some backup in saying I should have a stronger Amplifier and just be careful about how loud I turn up the volume. That means for that thing I would have to get like, what... a 150w Amplifier? My issue is more powerful amps are generally more expensive and I can't seem to find a good one with a good SNR in the price range I was hoping for. I suppose I could ditch that minor detail, don't really need 100+ SNR.
I am thinking of asking this different question on another post that will change much of this, as I think I have enough info from this post.
https://www.parts-express.com/Dayto...uetooth-Amp-Board-with-DSP-325-430?quantity=1
I was wondering if this Amplifier's DSP is per channel, and if it is does that mean I can put 2 tweeters and 2 woofers/full ranges across the 4 channels and use the DSP to make a custom filter for a custom crossover that is adjustable thus eliminating the need for a crossover?
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