Just put the parameters of the mid driver into winisd and model it with sealed of various sizes and see what you get. If you are going to cross it over high (say 500Hz) then provided you aren't getting peaking in that range you can make the volume quite small, and you should get better power handling to boot 
The 5L was just an example (and is probably bigger than most ever would be).
Graph shows my SB 4" driver modeled in the "ideal" 1.5L volume and a smaller 0.5L volume. You can see the effect of the smaller volume, but if you were crossing at 500 Hz it wouldn't be much of an issue.
The power handling is where it gets interesting. with 1.5L 5W is about the maximum without exceeding xmax. With 0.5L you can put 20W into it without exceeding xmax.
Also take into account that any enclosure you add for the mid is taking away volume in your 45L main cabinet
Tony.
The 5L was just an example (and is probably bigger than most ever would be). Graph shows my SB 4" driver modeled in the "ideal" 1.5L volume and a smaller 0.5L volume. You can see the effect of the smaller volume, but if you were crossing at 500 Hz it wouldn't be much of an issue.
The power handling is where it gets interesting. with 1.5L 5W is about the maximum without exceeding xmax. With 0.5L you can put 20W into it without exceeding xmax.
Also take into account that any enclosure you add for the mid is taking away volume in your 45L main cabinet
Tony.
Attachments
A sealed mid compartment's job is isolation if you are crossing over several octaves higher than the resonance. (usually) Larger does not hurt performance, but it is a waste of space. So, if yo have a 4 inch mid and the T/S parameters say it has a resonance say 80, and the model says it could be tuned to an F3 of 110 Hz in 2 L, but you are going to cross it over at 500, then half a liter or 10 liters would make no difference. Go ahead. Model it. Add the filter WinISD lets you.
Yes those sealed back mid's from the 60's were crossed over pretty high. They were cheap. Yes many speakers did not isolate the midrange. They were cheap.
This not a complicated issue. Isolate your mid in a well stuffed chamber so you reduce any reflections back through the cone. That's about all there is to it.
Yes those sealed back mid's from the 60's were crossed over pretty high. They were cheap. Yes many speakers did not isolate the midrange. They were cheap.
This not a complicated issue. Isolate your mid in a well stuffed chamber so you reduce any reflections back through the cone. That's about all there is to it.
Sure, it's usually a single cap in series, same as a closed back cone tweeter, at least two octaves above resonance, which ( I imagine ) is why all the component XOs from Tandy/RadioShack used 800and 1500Hz as the XO point
Proposing to use 8" SB23 as recommended by Wintermute with 4" Peerless 830992 as midwoofer which I already have with Peerless 1 " tweeter 812978 in my 40 litre box with 4 litres for mid woofer.
Assuming (!) 500-5000 Hz are best crossovers asper previous posts, I have struck a problem in that both WES Components and Speakerbits do not have 500HZ-5000HZ crossovers. Anyone know a source in Australia?
Thanks
Assuming (!) 500-5000 Hz are best crossovers asper previous posts, I have struck a problem in that both WES Components and Speakerbits do not have 500HZ-5000HZ crossovers. Anyone know a source in Australia?
Thanks
Stevenn you are going to have to design and built the XO your self if you want to use 4 liters for the mid, it will more than likely need a second order.
That little peerless woofer could cross over much lower than 500 but every time you go down in frequency costs increase because the coils have a lot of copper in them.
May I suggest you download J.Bagbys program ( free ) and play with it.
I now buy most of my components from
SpeakerBug, capacitors, inductors, resistors, crossover parts, speaker supplies
That little peerless woofer could cross over much lower than 500 but every time you go down in frequency costs increase because the coils have a lot of copper in them.
May I suggest you download J.Bagbys program ( free ) and play with it.
I now buy most of my components from
SpeakerBug, capacitors, inductors, resistors, crossover parts, speaker supplies
I'm with Moondog. Having cut my teeth on pre-built crossovers, it is not the way to go if you want real real quality. You might get lucky and have something that works ok, but chances are it won't.
At a bare minimum I would recommend looking at the manufacturers specs and seeing what the impedance is at your selected crossover frequencies, and working from there.
Ideally if you can get real impedance measurements you will be even further in front. It is not that hard if you have a sound card with line in, you can do it with a single resistor and a 3.5mm stereo cable cut in half.
Even better is if you have acoustic measurements of the drivers on the baffle, but even manufacturers curves traced with spltrace will give you a big head start.
If you don't feel like making any measurements, at least have a read of Allen's excellent sticky in this forum.
Also don't worry too much about whether 500 and 5000 are best. It will depend on the individual drivers. You need to look at what your 4" mid is doing up that high (it may well have breakup in this region. You might be better off crossing somewhere between 3 and 4K. I think a four inch driver will be well and truly beaming (becoming very directional) by 5K as well, which you don't necessarily want.
There are no hard and fast rules, the important thing is the end result, not necessarily how you got there
I'm assuming that moondogs reference was to Jeff's PCD (passive crossover designer) It's a great spreadsheet that really helps you get your head around how crossovers work and how various changes affect the result available here --> http://audio.claub.net/software/jbabgy/jbagby.html
Tony
At a bare minimum I would recommend looking at the manufacturers specs and seeing what the impedance is at your selected crossover frequencies, and working from there.
Ideally if you can get real impedance measurements you will be even further in front. It is not that hard if you have a sound card with line in, you can do it with a single resistor and a 3.5mm stereo cable cut in half.
Even better is if you have acoustic measurements of the drivers on the baffle, but even manufacturers curves traced with spltrace will give you a big head start.
If you don't feel like making any measurements, at least have a read of Allen's excellent sticky in this forum.
Also don't worry too much about whether 500 and 5000 are best. It will depend on the individual drivers. You need to look at what your 4" mid is doing up that high (it may well have breakup in this region. You might be better off crossing somewhere between 3 and 4K. I think a four inch driver will be well and truly beaming (becoming very directional) by 5K as well, which you don't necessarily want.
There are no hard and fast rules, the important thing is the end result, not necessarily how you got there
I'm assuming that moondogs reference was to Jeff's PCD (passive crossover designer) It's a great spreadsheet that really helps you get your head around how crossovers work and how various changes affect the result available here --> http://audio.claub.net/software/jbabgy/jbagby.html
Tony
hehe, I did a search for frd consortium and when I clicked the link it came up with some canadian pharmacy trying to sell me viagra I've just been having a look at the box modeling program (I normally use unibox). It looks nice! I like that it has the group delay modelling. I can't see any way to export the box response though...
Tony.
I've just been having a look at the box modeling program (I normally use unibox). It looks nice! I like that it has the group delay modelling. I can't see any way to export the box response though... Tony.
Have downloaded Bagley and my head is swimmimg....!
Even if I figured out the design, and bought all the components, I don't have much experience with a soldering iron and then my crossover may not work anyway.
Have found these 375-3000 Hz crossovers from Parts Express in USA.
Shipping is almost as much as crossovers!
Don't see much alternative other than taking a crash course for next 6 months in electronics...
I need a Panadol
Even if I figured out the design, and bought all the components, I don't have much experience with a soldering iron and then my crossover may not work anyway.
Have found these 375-3000 Hz crossovers from Parts Express in USA.
Shipping is almost as much as crossovers!
Don't see much alternative other than taking a crash course for next 6 months in electronics...
I need a Panadol
I don't disagree that this crossover stuff induces Panadol taking
. Also, US shipping seems to have shot up recently (it was never "good value", especially if you're in Australia). If you can find a source of reasonably-priced inductors, you're halfway there because they're the most highly-priced items in a crossover, if you discount some of the high-end capacitors. Try European suppliers perhaps- PE sells Jantzen inductors which are made in Poland. As for making a crossover yourself, it's not really as hard as it looks- the scary part is the design. Once you have that, a piece of thin MDF will do as a base, the various parts aren't all that hard to join up, minimal soldering skills are required. You could quite possibly use screw connectors and avoid soldering altogether, much more skilled afficionados might comment on that possibility.
You can also get pre-made crossover circuits reasonably cheaply out of China (say, AUD 25 each + quite cheap postage) and you then have the basic circuit, and if the inductors are "in the ballpark" it's quite cheap to change the capacitors. I used a pair from China, the caps are the red "Audiophile" type which it has been suggested should be changed, as 3 of them are 3.3 to 6uF, this wouldn't be overly expensive and is a course I will take in the near future to better suit my drivers and desired crossover points. Just be aware that stuff out of China takes forever to come, their postal system is far from efficient.
Steve, When you get to the point you are wanting to hook up a crossover, I can probably lend you the pre-builts out of my old three ways. They are ones I bought from Jaycar years ago and I think that they are 500Hz / 3000Hz crossover points.
From memory I paid about $80 each for them, and that is probably around 23 years ago so was quite a bit of money!! I do have another cheaper set (maybe) somewhere which were the ones I had before those. They had 800/5000 crossover points I think and sounded terrible in comparison with my drivers.
The "good" ones would at least allow you to do an evaluation of what a pre-made crossover could sound like. You might be entirely happy with it, but you might not be either
I bought my capacitors for my two way at partsconnexion (very good price on axon true caps), and for the inductors I wound my own. But speakerbug has very good prices on inductors if you aren't interested in winding your own
I can understand your reluctance at designing your own crossover. Probably a large part of the reason my MTM's sat unfinished for around 5 years was due to being scared to do the crossovers! In the end though I got there, and I couldn't be happier with the result.
Tony.
From memory I paid about $80 each for them, and that is probably around 23 years ago so was quite a bit of money!! I do have another cheaper set (maybe) somewhere which were the ones I had before those. They had 800/5000 crossover points I think and sounded terrible in comparison with my drivers.
The "good" ones would at least allow you to do an evaluation of what a pre-made crossover could sound like. You might be entirely happy with it, but you might not be either
I bought my capacitors for my two way at partsconnexion (very good price on axon true caps), and for the inductors I wound my own. But speakerbug has very good prices on inductors if you aren't interested in winding your own
I can understand your reluctance at designing your own crossover. Probably a large part of the reason my MTM's sat unfinished for around 5 years was due to being scared to do the crossovers! In the end though I got there, and I couldn't be happier with the result.
Tony.
I bought mine from Blackburn electric Wires Blackburn Electric Wires . whatever the metric equivalent of 14Gauge is. If you tell them you are doing coils for speaker crossovers they will give you the right sort of enamel.
They have a minimum 2KG purchase I think. From memory I paid about $70 back in 2010 I think. I only used 1/2 of it but for the number of coils I made it was probably less than 1/2 the price of buying pre made Solen ones (speaker bug didn't have 14Ga in the sizes I wanted). Before I got brave and wound my own, I was going to buy higher dcr ones from speakerbug. Check out my blog if you want a bit of background on how I made them
Tony.
They have a minimum 2KG purchase I think. From memory I paid about $70 back in 2010 I think. I only used 1/2 of it but for the number of coils I made it was probably less than 1/2 the price of buying pre made Solen ones (speaker bug didn't have 14Ga in the sizes I wanted). Before I got brave and wound my own, I was going to buy higher dcr ones from speakerbug. Check out my blog if you want a bit of background on how I made them
Tony.
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