Here are my questions towards the new 3-way speaker project of mine.
1) I’m looking for the dome midrange drivers that could work well under 600Hz. The desired corner frequency (-3dB point) for the high-pass section of these midranges is intended to employ at 550Hz with approximately 12dB/octave natural roll-off slope. And it will be combined with the 12dB/octave electrical slope to make the acoustical slope to be 24dB/octave. In brief, I’d like to use these mid-domes in place of the 4” cone midranges in my design.
What qualifications are required for that requirement, i.e., Fs shouldn't be lower than … Hz, Re should be in the range of … Ohms, etc.?
2) If the low frequency drive units used with those mid-domes are, of course, responsible for below 550Hz, would it be better or acceptable to use the subwoofer drive units instead of the traditional woofers for the low frequency section?
1) I’m looking for the dome midrange drivers that could work well under 600Hz. The desired corner frequency (-3dB point) for the high-pass section of these midranges is intended to employ at 550Hz with approximately 12dB/octave natural roll-off slope. And it will be combined with the 12dB/octave electrical slope to make the acoustical slope to be 24dB/octave. In brief, I’d like to use these mid-domes in place of the 4” cone midranges in my design.
What qualifications are required for that requirement, i.e., Fs shouldn't be lower than … Hz, Re should be in the range of … Ohms, etc.?
2) If the low frequency drive units used with those mid-domes are, of course, responsible for below 550Hz, would it be better or acceptable to use the subwoofer drive units instead of the traditional woofers for the low frequency section?
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You would need a measurement of the harmonic distortion, taken at the desired SPL.
That depends on your goals and the woofer. Modern subwoofers with shorting rings work fine up to surprisingly high frequencies.
Xmax, power handling, distortion measurement in the desired range, fs preferrably a octave below xo (at least below), if a passive xo the impedance peak messes with the filters function, so one might need a zobel.
And your required SPL, will be the limiting factor with a small mid dome crossing low.
Your desired XO frequency, should ideally be set by the dome and woofers directivity on the chosen baffle.
The ones best suited for use low in frequency, that are somewhat available would be ATC SM75, Scanspeak 8404, and Volt VM 752/3.
There is also the larger Bliesma M142's, or M74's if volume requirements are low or xo higher.
It is hard to answer without knowing more about the objectives for the speaker and why you are using a dome. Are you looking at 5" or 2" domes? With or without waveguide?
If it is a small dome then clean SPL will be a problem for main speakers in a room but less so for a desk speaker. If it is a large dome then resonant behaviour crossing to the tweeter is likely to be the main concern.
What is classified as a subwoofer or woofer is a bit vague these days. Subwoofers often have gross misbehaviour at the frequencies you are looking to cross and are often pretty inefficient in order to get deep bass extension.
If it is a small dome then clean SPL will be a problem for main speakers in a room but less so for a desk speaker. If it is a large dome then resonant behaviour crossing to the tweeter is likely to be the main concern.
What is classified as a subwoofer or woofer is a bit vague these days. Subwoofers often have gross misbehaviour at the frequencies you are looking to cross and are often pretty inefficient in order to get deep bass extension.
Why don't you check out Madisound's part pages? They have lots of useful recommendations there for midranges and cabinet sizes, including sealed midrange units which don't require box calculations.
Stay flexible on your crossover slopes, we often compromise db/octave for the sake of phase angle matching unless you have a stepped baffle or using a delay circuit.
Stay flexible on your crossover slopes, we often compromise db/octave for the sake of phase angle matching unless you have a stepped baffle or using a delay circuit.
Your desired mid dome does not exist.
Firstly, with the higer Qts it will drop off quicker (not that you should use them near the fs anyway). Secondly, you need to account for the bafflestep and behavior of the bass, phase, frequency response and impedance and therefore not predict how the crossover will look like before the fact, let alone know it before baffle dimensions and even drivers or anything of the speakers are known. If it was that easy, there would be only perfect speakers.
There might be subwoofer drivers which can do that but if you can't specify what is acceptable for you nobody will be able to answer that either.
To be bluntly, you want to know the grades of your kids in high school to chose which woman you want to have the children with. It doesn't work that way.
With all the help you can and likely will get here in the forum, that will not result in the speaker you're probably envisioning. I don't think you know what causes what in a speaker (and there's nothing wrong with that, everyone startet sometime) but just selecting 'the best' does not result in a good speaker. Moreover, your speaker which will be assembled with the remote help of the forum will likely be inferior to a speaker a seasoned speaker builder from this board (and there are a lot really capable ones!) which cost less than one single driver you're planning to use right now.
You can learn all that and the board got many ppl who can and will help you but right now you have to decide what your goal is, learning how to design and develop speakers or get as close to your dream speaker as possible. If it's the former, start with a 2-way. If it's the latter, build a speaker someone designed already.
With all the help you can and likely will get here in the forum, that will not result in the speaker you're probably envisioning. I don't think you know what causes what in a speaker (and there's nothing wrong with that, everyone startet sometime) but just selecting 'the best' does not result in a good speaker. Moreover, your speaker which will be assembled with the remote help of the forum will likely be inferior to a speaker a seasoned speaker builder from this board (and there are a lot really capable ones!) which cost less than one single driver you're planning to use right now.
You can learn all that and the board got many ppl who can and will help you but right now you have to decide what your goal is, learning how to design and develop speakers or get as close to your dream speaker as possible. If it's the former, start with a 2-way. If it's the latter, build a speaker someone designed already.