Hi,
Obviously a 8" midrange can be louder (and I'm guessing less harsh) than a 4" midrange, but how might the "speed/accuracy" (or transient response), especially in the high-mids, compare (appropriately-sized sealed chamber for each driver)?
More specifically, something like an 18 Sound 8M400 8 inch midrange vs. a Dayton Audio PC105 4 inch "full-range but you can use it as a midrange" (both 8 ohm versions).
The 4" is currently being run 500Hz-3.5KHz between a sealed-enclosed 12" woofer and the tweeter, but I'd want to run the 8" 200Hz-3.5KHz.
Looking forward to hearing back 🙂
Obviously a 8" midrange can be louder (and I'm guessing less harsh) than a 4" midrange, but how might the "speed/accuracy" (or transient response), especially in the high-mids, compare (appropriately-sized sealed chamber for each driver)?
More specifically, something like an 18 Sound 8M400 8 inch midrange vs. a Dayton Audio PC105 4 inch "full-range but you can use it as a midrange" (both 8 ohm versions).
The 4" is currently being run 500Hz-3.5KHz between a sealed-enclosed 12" woofer and the tweeter, but I'd want to run the 8" 200Hz-3.5KHz.
Looking forward to hearing back 🙂
i guess a 4" acts more like a point source with better imaging due to ctc. It is easier to match the off-axis reponse (directivity) of the tweeter. Less distortion over 3kHz
Why the 200hz low frequency crossover point?
An 8” midrange will be strongly beaming at 3.5khz so the on axis and off axis response will be significantly different.
I’ve tried lots of points with 8” mids and found 2..5k be about the max……….1.6k to be optimal. A waveguide loaded some tweeter, planar or compression driver with horn would then be needed. Split the difference at 2k and a robust dome of 29mm or more can do the trick…..but there’s tradeoffs……power handling and power compression in the treble region would be your limiting factor
I’d not use an 8” midrange unless the lower midbass response of the woofer was choppy ……a 15” woofer crossed over at 250hz is something special……enough surface displacement to give drums the tactile experience they deserve.
An 8” midrange will be strongly beaming at 3.5khz so the on axis and off axis response will be significantly different.
I’ve tried lots of points with 8” mids and found 2..5k be about the max……….1.6k to be optimal. A waveguide loaded some tweeter, planar or compression driver with horn would then be needed. Split the difference at 2k and a robust dome of 29mm or more can do the trick…..but there’s tradeoffs……power handling and power compression in the treble region would be your limiting factor
I’d not use an 8” midrange unless the lower midbass response of the woofer was choppy ……a 15” woofer crossed over at 250hz is something special……enough surface displacement to give drums the tactile experience they deserve.
4" is too small. Golden mean for hi-fi midrange is 5" or 6", especially when it have to play 200 Hz.
18Sound 8M400 is extremely efficient pro midrange with lightspeed transients and explosive dynamics. (unavailable, new model is 8M400F) No need for high-pass filter, if mounted in a small closed chamber. Needs RLC notch filter at 900 Hz.
Which tweeter and 12" woofer?
Thanks all for the replies 🙂
Currently I have pair of 1.6 cu ft sealed enclosures with 0.1 cu ft midrange tubes in them, with of course (without going into detail) acoustic material for the woofers and midranges.
Drivers are all currently Dayton - each enclosure has a DC300-8 twelve-inch woofer, PC105-8 four-inch "full range" (midrange), and DC25T-8 one-inch tweeter.
Each enclosure has an off-the-shelf 3-way passive crossover (PRV Audio 3DF500/3500), installed before I first came onto this forum and I was told to avoid off-the-shelf passive crossovers 😛
My source is my PC and I use 31-band software EQ for correction, including the huge midrange cuts covering for the non-existent physical notch filters (obviously I can sort out the crossovers at a later date, to a point where I don't have to use so much EQ).
I like the woofers very much - they really do give the "tight response with a powerful kick in sealed enclosures" that Dayton only advertise for the 12" version, so they're staying (I acknowledge the mention of a 15" woofer though).
Yeah, 4" is too small for midrange - even EQd, they're harsh and strained at high volumes, at least these 4" drivers, but yeah, maybe it's 4" in general.
Are there any cone midrange drivers that don't need notch filters, or are they always needed?
I can use a 250Hz woofer-to-midrange crossover if it's recommended instead of 200Hz.
I was thinking of the 8-inch 18 Sound 8M400F for the midrange, with a HiVi RT2H-A as the tweeter, but now I realise that the 8M400F will ideally want to be low-passed at a lower frequency than 3.5KHz (like 1.6KHz to 2.5KHz) - would one of those "planar mid-tweeter" drivers allow that to happen and work well?
I like the sound (not yet literally) of lightspeed transients from the 8M400(F) - it's more in the high-mid region I'm concerned about with a "big" driver like that, or are they as good up there (or even better) than some 5" or 6" midrange drivers?
Currently I have pair of 1.6 cu ft sealed enclosures with 0.1 cu ft midrange tubes in them, with of course (without going into detail) acoustic material for the woofers and midranges.
Drivers are all currently Dayton - each enclosure has a DC300-8 twelve-inch woofer, PC105-8 four-inch "full range" (midrange), and DC25T-8 one-inch tweeter.
Each enclosure has an off-the-shelf 3-way passive crossover (PRV Audio 3DF500/3500), installed before I first came onto this forum and I was told to avoid off-the-shelf passive crossovers 😛
My source is my PC and I use 31-band software EQ for correction, including the huge midrange cuts covering for the non-existent physical notch filters (obviously I can sort out the crossovers at a later date, to a point where I don't have to use so much EQ).
I like the woofers very much - they really do give the "tight response with a powerful kick in sealed enclosures" that Dayton only advertise for the 12" version, so they're staying (I acknowledge the mention of a 15" woofer though).
Yeah, 4" is too small for midrange - even EQd, they're harsh and strained at high volumes, at least these 4" drivers, but yeah, maybe it's 4" in general.
Are there any cone midrange drivers that don't need notch filters, or are they always needed?
I can use a 250Hz woofer-to-midrange crossover if it's recommended instead of 200Hz.
I was thinking of the 8-inch 18 Sound 8M400F for the midrange, with a HiVi RT2H-A as the tweeter, but now I realise that the 8M400F will ideally want to be low-passed at a lower frequency than 3.5KHz (like 1.6KHz to 2.5KHz) - would one of those "planar mid-tweeter" drivers allow that to happen and work well?
I like the sound (not yet literally) of lightspeed transients from the 8M400(F) - it's more in the high-mid region I'm concerned about with a "big" driver like that, or are they as good up there (or even better) than some 5" or 6" midrange drivers?
No rules here, Yes a 8" can be better than a 5" 6" in the high mid and I have seen some 8" crossed as high as 6/7kHz. We have some french speaker 8"+tweeter with high frequency crossover (Esprit Amelia 7kHz). Depend on how do you build the speaker 🙂
No, only 18Sound 8M400 need EQ at 900 Hz with -4 dB, but you have equalizer to do that, so it is not a problem.
There are many other midrange or midbass drivers with very flat frequency response - beside crossover, they need only BSC compensation (as a part of the low-pass filter). Bigger driver (6" or 8") with 8-ohm impedance often don't need high-pass filter, because 12dB/octave roll-of in the low frequencies is natural for closed box loudspeakers.
Last edited:
Lower frequency demand bigger value of inductors and capacitors. Otherwise not really important if midrange is bigger than 4".
Ideal size of the midrange depends very much the on other drivers - woofer and tweeter. OP has large 12" woofers with above average sensitivity, so larger then 4" midrange comes naturally.
No such thing as " too small"
You want it to be small, so the tweeter can be small. Then center to center mounting is tight.
Since you haven't seen off axis response of the system. Mounting distance is a huge deal with speaker design.
The only tradeoff with small drivers and direct radiators. Is small drivers have lower sensitivity.
Max midrange size is more like 6.5 inch which will offer more sensitivity.
Tradeoff is your looking at large tweeters to cross low enough.
Same with 8"
Should know end of the road is 1200 to 1600 Hz that is it, off axis.
Same thing, big challenge to design a crossover and a large tweeter is needed to cross that low.
And 3rd or 4th order crossovers mandatory to reduce distortion at high levels / high SPL
With a proper higher order crossover for the " small" midrange.
Distortion could be reduced, and higher cost drivers of course expand that.
But even the cheapo Dayton's work rather well on the right crossover.
For all we know it is getting blasted with odd EQ boosting and cutting to fix the response.
Once you explore and see off axis data and then juggle phase response in crossover design.
Will be more aware of roller coaster responses and roller coaster impedance curves.
Which can be corrected for a better performing system.
Rather real measurement or using Dayton FRD data to generate accurate off axis full space data.
Then will appreciate why small mids are so useful, and then stay 2x above their resonant frequency
with higher order filters and reduce the distortion you are hearing.
You want it to be small, so the tweeter can be small. Then center to center mounting is tight.
Since you haven't seen off axis response of the system. Mounting distance is a huge deal with speaker design.
The only tradeoff with small drivers and direct radiators. Is small drivers have lower sensitivity.
Max midrange size is more like 6.5 inch which will offer more sensitivity.
Tradeoff is your looking at large tweeters to cross low enough.
Same with 8"
Should know end of the road is 1200 to 1600 Hz that is it, off axis.
Same thing, big challenge to design a crossover and a large tweeter is needed to cross that low.
And 3rd or 4th order crossovers mandatory to reduce distortion at high levels / high SPL
With a proper higher order crossover for the " small" midrange.
Distortion could be reduced, and higher cost drivers of course expand that.
But even the cheapo Dayton's work rather well on the right crossover.
For all we know it is getting blasted with odd EQ boosting and cutting to fix the response.
Once you explore and see off axis data and then juggle phase response in crossover design.
Will be more aware of roller coaster responses and roller coaster impedance curves.
Which can be corrected for a better performing system.
Rather real measurement or using Dayton FRD data to generate accurate off axis full space data.
Then will appreciate why small mids are so useful, and then stay 2x above their resonant frequency
with higher order filters and reduce the distortion you are hearing.
I am old enough to remember that majority of 2-way bookshelf speakers in my time were equipped with 8" woofers. Nowadays 8" woofer can be found only in larger tower/floor-standing loudspeakers. In this modern times 12" woofers are very, very rare.
4" midrange may work well with 12" woofer only with high enough crossover point. The OP wants 200-250 Hz woofer-mid crossover, so 5" or 6.5" midrange will work better.
Yes, but majority of 2-way speakers use 5.25" or 6.5" mid-woofers with tweeters without waveguides crossed at 2.5 kHz - 3.5 kHz and (almost) nobody complaints. Even 4" mid-woofers have the same problem (or not).
I made several different models of loudspeakers with eight-inch driver 18Sound 8M400(F) crossed at 2.5 kHz - no problems at all.
Last edited:
Sonce with respect it depends on too may factors to rule out a 4" crossing at 250Hz, my personal favourite was the Vifa P-11, either the more robust WH version or the dedicated midrange version MH or the later PL-11 which combined the best features of both could be crossed 2nd electrical at 200 with no problems in a medium powered [ 100W] system
http://www.troelsgravesen.dk/ScanSpeak-3WC-C/PL11MH09-08.pdf
Personally I think Troels could have crossed much lower but costs would have doubled. Bi-Amping 300Hz 4th is simple and cheap and easy.
MTM with a Neo tweeter and SPL levels easily match a big woofer
http://www.troelsgravesen.dk/ScanSpeak-3WC-C/PL11MH09-08.pdf
Personally I think Troels could have crossed much lower but costs would have doubled. Bi-Amping 300Hz 4th is simple and cheap and easy.
MTM with a Neo tweeter and SPL levels easily match a big woofer
Yes, too many different/contradicting factors for a general, "one size fits all" advice.
Passive crossover at low frequency demands big and expensive capacitors and inductors. To get around that, in several different projects I used large 6,5"/8"/10" midrange/midwoofer (8-ohm, low Qts) mounted in a small closed enclosure - that is conventional closed box loudspeaker with natural acoustical 12dB/octave high-pass filter with F3 at about 100 - 250 Hz. No need for expensive passive electrical high-pass midrange filter! For all-passive systems, woofers must have 8-ohm impedance, to not allow total nominal impedance to be lower than 4 ohms. This is the solution I am proposing to the OP.
Active crossover and two amplifiers is another viable solution.
Maximum SPL of MTM with 4" midranges easily match a big woofer, but one 8" (or 6") midrange also can do that, if not better.
Choices, choices...
Last edited: