Can we find approximate impedances, i.e., 4, 6, 8 Ohms, of the drivers from crossover values?
If so, attached is the example of crossovers with unknown drivers’ impedances. Could anyone please help to find them?
TT (woofer) = …. Ohms
MT (midrange) = …. Ohms
HT (tweeter) = …. Ohms
In fact, I’ve tried simulations with various values of impedance on each driver, and found so many possible combinations. They made me more confused. So, please help me to get it.
If so, attached is the example of crossovers with unknown drivers’ impedances. Could anyone please help to find them?
TT (woofer) = …. Ohms
MT (midrange) = …. Ohms
HT (tweeter) = …. Ohms
In fact, I’ve tried simulations with various values of impedance on each driver, and found so many possible combinations. They made me more confused. So, please help me to get it.
You are trying to get around measuring impedance, TSB and response in cabinet with some kind of trick for quite some time if I remember right..
Please accept there is no magic trick to get around learning to measure and study a lot more literature if you want to "build" a speaker.
We do not live in a world of dragons, spirits and flying goats, it all boils down to solid science and hardware.
For those who don't like all that reading and learning, there are ready designed, proven kit's. The best thing invented after fried potatoes.
Please accept there is no magic trick to get around learning to measure and study a lot more literature if you want to "build" a speaker.
We do not live in a world of dragons, spirits and flying goats, it all boils down to solid science and hardware.
For those who don't like all that reading and learning, there are ready designed, proven kit's. The best thing invented after fried potatoes.
Where did you find the crossover scheme?
In other words: what speaker is this and do you have the datasheet? Many times the crossover point is stated and you can iterate from that, or maybe even its nominal impedance is stated. If its a domestic speaker from way back then I would assume it’s all 8 ohm.
In other words: what speaker is this and do you have the datasheet? Many times the crossover point is stated and you can iterate from that, or maybe even its nominal impedance is stated. If its a domestic speaker from way back then I would assume it’s all 8 ohm.
Sorry, I didn't tell everyone a bit about the cause of the problem.
The schematic is from Braun LS80 speakers.
I obtained the crossover networks, without any drivers. And I already have all drivers (W, M, T) of ADS L780/2 speakers. I'm thinking to mate them together. But the problem is I don't know the impedances of the LS80's drivers. So I cannot create the crossovers' transfer function.
The schematic is from Braun LS80 speakers.
I obtained the crossover networks, without any drivers. And I already have all drivers (W, M, T) of ADS L780/2 speakers. I'm thinking to mate them together. But the problem is I don't know the impedances of the LS80's drivers. So I cannot create the crossovers' transfer function.
Impedance is a complex function of the frequency, not one number. Important is also efficiency and the enclosure data. otherwise your "simulations" don't mean anything
Why don't you take the responses you simulate and the responses you measure, calculate the difference and use it as a lazy error compensation quantity?
Why not simply use an equaliser. Forget changing the crossover, just keep the EQ in place?
Why not simply use an equaliser. Forget changing the crossover, just keep the EQ in place?
Second-order filter frequency ~ 5khz/sqrt(mH*uF) independent of driver impedance. So a quick glance gives LPF 450hz and HPF 5500hz. Impedance affects the precise shape of the response curve not its (2nd-order filter) crossover frequency. See the other thread about "lessons for novice".
For some reason you got these drivers and crossover for free, OK. Anyway, please realize, these where not very good speakers at their time. Their sound never matched their reputation. Just because they were "BRAUN MADE IN GERMANY" gave them some special appeal. Plus the design was quite puristic.
Next, understand that these drivers age. The ferro fluid dries out. They are much worse than new. Old, worn out.
The next problem with "understand": you do not make crossover from thin air. You need measurements of chassis inside the baffle you want to use.
Throw away the junk and get a measuring microphone, than learn how to use it. Build a simple rig to measure impedance and TSP. Can all be done in REW. Tutorials are well written.
Next, understand that these drivers age. The ferro fluid dries out. They are much worse than new. Old, worn out.
The next problem with "understand": you do not make crossover from thin air. You need measurements of chassis inside the baffle you want to use.
Throw away the junk and get a measuring microphone, than learn how to use it. Build a simple rig to measure impedance and TSP. Can all be done in REW. Tutorials are well written.
@wchang close, it is 700 and 5000.
I have looked of some of the BRAUN crossovers, the seem to be mainly made with some work sheets that were used at that time.
Around 1980 some honest people told us the truth, that these work sheets are 100% useless. All you can do with them, if you are lucky, is to prevent your tweeter from getting overloaded and burned.
This is, of course bad news for those selling unknowing DIYS speaker builders various chassis with huge profit. So there are still people around, that tell you they are usefull and people like me, who call for individulal crossovers, are taking things too serious because of a few % in sound quality.
No, it is not a few %, it is about a good and a lousy result.
In Hamburg there is "Open Air", a DIYS speaker shop existing 40 years now. If you go there and buy some chassis, the owner will do a crossover for you, for free! He will take a paper bag, paint a schematic on it and then put a few parts in the same bag. No question, he calls all his 1 minute developments high end speaker! People buy it. For 40 years now. His shop is close to the university, so every year there are new victims for this developer.
What you get there is about the same what these BRAUN speakers are: Some box that turns electric signals into noise.
The good thing about this shop, he will sell you any well developed kit and there are a thousand or more to choose from. You only have to look.
I have about 40 years of German DIYS speaker building literature. Why the hell do people insist on building bad speakers when there are so many well developed kit's?
I have looked of some of the BRAUN crossovers, the seem to be mainly made with some work sheets that were used at that time.
Around 1980 some honest people told us the truth, that these work sheets are 100% useless. All you can do with them, if you are lucky, is to prevent your tweeter from getting overloaded and burned.
This is, of course bad news for those selling unknowing DIYS speaker builders various chassis with huge profit. So there are still people around, that tell you they are usefull and people like me, who call for individulal crossovers, are taking things too serious because of a few % in sound quality.
No, it is not a few %, it is about a good and a lousy result.
In Hamburg there is "Open Air", a DIYS speaker shop existing 40 years now. If you go there and buy some chassis, the owner will do a crossover for you, for free! He will take a paper bag, paint a schematic on it and then put a few parts in the same bag. No question, he calls all his 1 minute developments high end speaker! People buy it. For 40 years now. His shop is close to the university, so every year there are new victims for this developer.
What you get there is about the same what these BRAUN speakers are: Some box that turns electric signals into noise.
The good thing about this shop, he will sell you any well developed kit and there are a thousand or more to choose from. You only have to look.
I have about 40 years of German DIYS speaker building literature. Why the hell do people insist on building bad speakers when there are so many well developed kit's?
If you have the crossovers and the drivers, you can put them together and done. Or do you think you can do a better crossover than the factory one without able to measure an impedance response or even a nominal impadance?
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Are those ADS drive units identical to the ones in the Braun LS80? Or if not, do they have identical complex (frequency varying) impedances, and identical frequency / phase responses when mounted on an identical baffle design to the Braun LS80? If not, the crossover network you say you have obtained is totally worthless except a/ in current form potentially stopping the HF driver burning out, and b/ as a very limited source of parts for future projects that might happen to require the component types and values. You've been told in various ways about drive units having different frequency, phase & impedance responses (which themselves vary depending on the box / baffle they are on) over the many threads you've started, but you don't seem to have listened. So, repeating some of the above (and from elsewhere):
- Loudspeaker drive units are not resistors: nominal impedance values are just an approximate guide, mainly for basic amplifier matching, and the actual impedance varies significantly with frequency. Different drive units have different impedance characteristics, even if they are lumped into the same nominal value
- Loudspeaker drive units do not have a perfectly flat frequency response from 0Hz to infinitely high. They all vary with design, and in most half-decent cases upward, the actual frequency response of the drive units (which as noted also varies from the IB curve when mounted on a real-world baffle in non-coincident positions) is taken into account when designing the crossover.
- The notional electrical transfer function alone is worthless, even if you account for the real frequency-varying impedance load rather than some flat resistive nominal, because the frequency & phase responses themselves need to be factored in. It's a combination of the electrical and acoustical transfer functions that we need to work with.
@YSDR
I’m sorry for trying to find the starting point of the project by asking for a help to find the unknown “driver’s” impedances that I don’t own them.
And I don’t think I can make anything better than the factory design. But, sorry again, this is a Frankenstein project—a lot of compromises here.
Finally, it’s beyond my ability to start doing anything without any knowing of the initial values, i.e., the impedance of drivers where the crossovers were designed to be used with.
@Scottmoose
I know speakers are not resistors, I believe at least the close values used is better than knowing nothing about the old crossovers. Imagine if the crossovers were designed to be used with 8:6:4 Ohms for W:M:T, but you tweak/adjust the new crossovers based on 4:8:6 Ohms (W:M:T), what will the results be? Do you understand what I am trying to say?
I’m sorry for trying to find the starting point of the project by asking for a help to find the unknown “driver’s” impedances that I don’t own them.
And I don’t think I can make anything better than the factory design. But, sorry again, this is a Frankenstein project—a lot of compromises here.
Finally, it’s beyond my ability to start doing anything without any knowing of the initial values, i.e., the impedance of drivers where the crossovers were designed to be used with.
@Scottmoose
I know speakers are not resistors, I believe at least the close values used is better than knowing nothing about the old crossovers. Imagine if the crossovers were designed to be used with 8:6:4 Ohms for W:M:T, but you tweak/adjust the new crossovers based on 4:8:6 Ohms (W:M:T), what will the results be? Do you understand what I am trying to say?
All I see with your posts is a clear sign of you ignoring any advice and returning to some mystical resistance value phantasies.
You seem to see the basics of speaker construction in some useless number, which is 4, 6 or 8.
Don't you even have a multimeter to measure the resistance of a voice coil? Which will give you your urgently desired and just as useless number of static Ohm's. The Chinese do these meters, starting around 2US$. Too much for your project?
You do not design a crossover for some impedance, you do it for a frequency response. You don't like that idea, but that's how the world turns.
You seem to see the basics of speaker construction in some useless number, which is 4, 6 or 8.
Don't you even have a multimeter to measure the resistance of a voice coil? Which will give you your urgently desired and just as useless number of static Ohm's. The Chinese do these meters, starting around 2US$. Too much for your project?
You do not design a crossover for some impedance, you do it for a frequency response. You don't like that idea, but that's how the world turns.
How do you tell the seller about the spec when buying the tweeters at the shop, please? Don't you tell him you need 4 Ohms tweeters or you show the seller the desired impedance graph printed from your home?
And, actually, I use a RLC meter rather than a multi-meter.
Thank you anyway
Except you apparently don't know anything about the new one either. How do you know this random filter you have obtained 'are at least the close values'? That's at best a wild guess.
Some basic realities. Based on what you've said so far:
- You don't even know the nominal impedance of the 'new' drive units, let alone their frequency varying IB impedance, or real-world, in-box impedances
- You don't know the on-baffle frequency response of the old drivers, or their phase relationships
- You don't know the on-baffle frequency response of the 'new' drivers, or their phase relationships in the same or different conditions to the original
Nobody can know, for the reasons above, and also because you're not asking a question that has an answer, even if you did have all of the above.
Assuming all the new drive units were identical in every single respect to the previous ones, apart from the differerence in impedance (and the new ones have the same trending, just at a different level), then you would simply adjust the values for their equivalents, assuming the original provided the desired results in the first place. However, it's almost unknown for there to be so little variation between drive units of different rated impedances, even in the same model range. If they are totally different units, from different manufacturers, as appears to be the case here, then you haven't got a clue what the results will be unless there is some actual data available.
The nominal resistance or impedance of a speaker is defined in some norm. It gives you an idea what load it will be for an amp.
If I build a 2-way speaker, tweeter-woofer, I take 4 Ohm chassis. If two woofer are used, like in a M-T-M I pick the 8 Ohm version for having 4 Ohm nominal, after using them in parallel. There are even 2 Ohm and 16 Ohm speaker because of this.
It has nothing to do with crossover building.
If you have chassis without a clean data sheet, measure them yourself or just don't use them. In case of the 40 year old BRAUN chassis, leaving them to the museum would be a good idea, right with the crossover you got.
I think no one here understands what you want and you seem to have some motive not to tell it.
This leads nowhere.
If I build a 2-way speaker, tweeter-woofer, I take 4 Ohm chassis. If two woofer are used, like in a M-T-M I pick the 8 Ohm version for having 4 Ohm nominal, after using them in parallel. There are even 2 Ohm and 16 Ohm speaker because of this.
It has nothing to do with crossover building.
If you have chassis without a clean data sheet, measure them yourself or just don't use them. In case of the 40 year old BRAUN chassis, leaving them to the museum would be a good idea, right with the crossover you got.
I think no one here understands what you want and you seem to have some motive not to tell it.
This leads nowhere.
Well, I will describe again for what I want to do.
I have ADS L780/2’s drivers; woofers, midranges, and tweeters. Basically, all of them are measured 4 Ohms resistance (Re).
Then, I got the crossover networks of Braun LS80 speakers. I’d like to use them with the ADS’s drivers. But, the problem is I don’t know how much impedance the crossovers were designed to be used with each driver. Or, in other words, I don’t know the impedances of each driver in the Braun LS80.
If all drivers of the LS80 are rated 4 Ohms, same as those of the L780/2, I will mate the crossovers and drivers directly/without any modifications (I could accept the errors as I reckon the drivers and enclosures aren’t already identical between those two speakers).
However, if the drivers of the LS80 aren’t rated 4 Ohms for all units; for example, the woofers are rated at 6 Ohms, etc. Modifications on the crossovers will have been required. That’s all.