Hi,
This is continued discussion from this thread. I again confess I am not building anything; this would be just for learning purpose. I was mainly interested in only technical discussion as subjective preferences vary. Question was about maximum frequency range achievable (Specially lower end) from a two way (only two drivers) speaker system. I presume 20khz would be easily achieved.
I have zero knowledge of speaker design but I have read debates about ported vs sealed enclosures, bass preference, low frequency music contents etc. To avoid that lets put some specific goals, constraints, preferences and conditions in the design. Obviously these are not 'THE' best design choices but its good if we narrow down to something and reduce options available to make the discussion fruitful.
1) Only two drivers.
2) Sealed enclosure.
3) Drivers currently available for this purpose.
4) Linear response.
5) should sustain as much sound pressure as possible at reference level.
Thanks and regards. 🙂
This is continued discussion from this thread. I again confess I am not building anything; this would be just for learning purpose. I was mainly interested in only technical discussion as subjective preferences vary. Question was about maximum frequency range achievable (Specially lower end) from a two way (only two drivers) speaker system. I presume 20khz would be easily achieved.
I have zero knowledge of speaker design but I have read debates about ported vs sealed enclosures, bass preference, low frequency music contents etc. To avoid that lets put some specific goals, constraints, preferences and conditions in the design. Obviously these are not 'THE' best design choices but its good if we narrow down to something and reduce options available to make the discussion fruitful.
1) Only two drivers.
2) Sealed enclosure.
3) Drivers currently available for this purpose.
4) Linear response.
5) should sustain as much sound pressure as possible at reference level.
Thanks and regards. 🙂
The JBL M2 would be an example of a design meeting your criteria other than #2.
Variations of this type of design have been used since the 1940s for studio monitoring.
M2 Master Reference Monitor Products | JBL Professional
A sealed enclosure compromises #5.
Linear response limits the LF corner to around 40 Hz in a "reference level" 2 way speaker, to go another octave flat (20 Hz response) at high SPL would compromise fidelity in the 400-800 Hz range.
JBL M2 are not sealed though!
If you look at design with sealed cabinet, it seems they start to roll off at around 60hz max...
You shouldnt restrict your search on sealed vs ported.
If you look at design with sealed cabinet, it seems they start to roll off at around 60hz max...
You shouldnt restrict your search on sealed vs ported.
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"TWO SPEAKERS" A coaxial compression driver, and a 18" woofer in a large sealed box with equalization.
(1) SEOS24 wave guide with BMS 4954ND coaxial compression driver
(2) 18" woofer like Lambda TD18H+ Mms=164g, Le=0.4mH, Xmax= 14mm 1000W
Dual AE TD18H+ Mains -TD15M center by Lukeamdman
Specifications:
■Loudspeaker Type:
2 Way active with DSP @450Hz
Passive Xover for BMS coax compression driver
■Frequency Response Range: 20Hz-20KHz
■Bass/mid-bass: TD18H+ (8ohm) woofer in 4.5cu.ft sealed ~99db/w before room gain
■High frequency: BMS 4594ND coaxial compression driver Denovo SEOS-24 wave guide
***The JBL M2 coaxial horn could also be mated with a 18" sealed+equalized woofer.
(1) SEOS24 wave guide with BMS 4954ND coaxial compression driver
(2) 18" woofer like Lambda TD18H+ Mms=164g, Le=0.4mH, Xmax= 14mm 1000W
Dual AE TD18H+ Mains -TD15M center by Lukeamdman
Specifications:
■Loudspeaker Type:
2 Way active with DSP @450Hz
Passive Xover for BMS coax compression driver
■Frequency Response Range: 20Hz-20KHz
■Bass/mid-bass: TD18H+ (8ohm) woofer in 4.5cu.ft sealed ~99db/w before room gain
■High frequency: BMS 4594ND coaxial compression driver Denovo SEOS-24 wave guide
***The JBL M2 coaxial horn could also be mated with a 18" sealed+equalized woofer.
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I assume you meant an actual two way, not just a bookshelf monitor. So hear goes, 20-20k two way...
https://www.perrymarshall.com/articles/ultimate2way/
https://www.perrymarshall.com/articles/ultimate2way/
I built these 10 X 19 X 9 inch bookshelf speakers that I think sound VERY good. The tweeter is actually not hooked up. All 3 drivers come out to banana jacks on the back. There's an 8 inch kevlar woofer, and a 3 inch Vifa TC9FD mid, acting as mid and tweeter. It's bi-amped with X = 500HZ 4 pole LR, and I've got active EQ that pumps up the low bass so it's acoustically pretty flat down to 30HZ. It goes as loud as I ever want in my bedroom. I built a 4 channel LM3886 power amp for it that delivers 50watts rms per driver. 2 way, 30HZ - 16kHZ, no crossover in the frequencies where the ear is most sensitive, sounds great.
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In essence what you all are saying is maintaing SPL while extending the lower end is little challanging. Specially for a sealed enclosure. Wouldn't stiff and extremely light material with larger cone area solve the problem somewhat ? Thanks for the inputs.
Regards.
Regards.
Larger drivers can be more efficient. In essence you will find you can get 20Hz at some reasonable efficiency figure, I don't think it matters too much. You'll probably have other troubles getting the response right in a room, and find subs will help anyway, not for their efficiency or bass, but their location. This makes it much easier to get efficiency with two way mains.
I built some dual 15 two-ways that were -3dB at 28hz and were 107dB/2.83V/1M, but they were a 6th order vented design.
A 2 cu ft 2nd order sealed box with an F3 of 30hz can only be 0.18% efficient (84.55dB).
A 2 cu ft 4th order vented box with an F3 of 30hz can only be 0.36% efficient (87.56dB).
A 2 cu ft 6th order vented box with an F3 of 30hz can only be 0.90% efficient (91.54dB).
A 2 cu ft 2nd order sealed box with an F3 of 30hz can only be 0.18% efficient (84.55dB).
A 2 cu ft 4th order vented box with an F3 of 30hz can only be 0.36% efficient (87.56dB).
A 2 cu ft 6th order vented box with an F3 of 30hz can only be 0.90% efficient (91.54dB).
a 2 way ?
I fail to understand why there is such fascination for a 2 way.
Yes, I understand it falls under the "keep it simple" rule, but it
has compromises just as any other system does.
I fail to understand why there is such fascination for a 2 way.
Yes, I understand it falls under the "keep it simple" rule, but it
has compromises just as any other system does.
I like this quote from that page:
"The oft-referenced Fletcher-Munson curves show that we hear best in the 1000 Hz – 5000 Hz band. Any anomalies in the crossover range become blazingly obvious. Moving the crossover out of that range reduces the severity of the problem."
Marco
No fascination for 2 ways ScottL. It would be decades since the inventions of loudspeaker. With modern measuring, simulations, advanced materials I was just curious how much can be achieved.
Never thought of Coaxials (Single) and Wideband+12" driver mentioned by linesource and scottG. Any significant pros or cons of both the designs?
Thanks Allen. An article about subwoofer and room interaction would be highly appreciated ?
Regards.
Never thought of Coaxials (Single) and Wideband+12" driver mentioned by linesource and scottG. Any significant pros or cons of both the designs?
Thanks Allen. An article about subwoofer and room interaction would be highly appreciated ?
Regards.
I'd probably go for an Alpair 10 or 12P, which can achieve respectable LF response on their own, and then pick the most evil looking sub driver you can find. Probably 18" or so, at least 20mm one-way travel. Throw a couple of kW in there and EQ flat to 16Hz.
Active crossover at 80Hz should do nicely.
Something like this for LF.
RE Audio XXX18-v2-2 18" Cast Frame DVC Subwoofer Driver 2+2 Ohm
But you'll need serious power and EQ to get the LF extension in a smallish cabinet.
Chris
Active crossover at 80Hz should do nicely.
Something like this for LF.
RE Audio XXX18-v2-2 18" Cast Frame DVC Subwoofer Driver 2+2 Ohm
But you'll need serious power and EQ to get the LF extension in a smallish cabinet.
Chris
More than "a little".
The larger the cone area, the more moving mass required for a given "stiffness". More moving mass lowers the crossover point that can be used before cone breakup, as does larger cone dimensions, which start to narrow dispersion at a lower frequency.
The trade offs have dictated that the best sounding wide range two way that can play at "reference level" ends up being a ported 15" and a high frequency compression driver.
If you eliminate "reference level" from your criteria, all sorts of sealed options become viable.
Honestly, there are far too many undefined parameters given in the original post. What is meant by "linear response"? "reference level"? etc?
This thread is pretty meaningless without fully defining the parameters, otherwise you can bend them to allow anything or nothing.
This thread is pretty meaningless without fully defining the parameters, otherwise you can bend them to allow anything or nothing.
To get 20Hz sealed at standard levels will require multiple large drivers and quite a lot of power. Large drivers that reach 20Hz will force a crossover well below 1kHz which will dictate a largish high frequency driver making reaching 20kHz a challenge. It is doable but there will be size, cost and sound quality penalties. A 3 or 4 way is a significantly more reasonable choice.
If you're using a subwoofer+fullrange+DSP you can pretty much get 20hz-20khz flat in a sealed enclosure.
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