Gentlemen, what would your thoughts on a DiySoundGroup Sentinel 15, tuned lower in a larger box? I've read of 6cft boxes dropping the range into the lower 30 hz range. I do want to stay strictly 2 channel, with resolution and impact. It uses a 15 Deltalight, Dna 360 cd on a SEOS 15 wg, with a 1k x-over. I've been researching a lot of different options, and agonizing over what direction would be the most logical to go in. I am a big fan of the dynamics and clarity that cd's offer, but I have never had a speaker for home use that used anything other than domes (Alu, Ti, various soft domes). I could envision this being a poor mans version of a 4367. Size is not of too much relevance, but I would want whatever I build to play well in a large bedroom, as well as fill up a larger downstairs. I have no doubts on the latter, but the former may be a bit on the overkill side. Thank you all in advance. Glenn.
here's a siim 4th and 6th order bass reflex 151 liters , fb ~33Hz
you can see that around 50Hz, excursion is at a maximum and limited
to about 60 watts input at that frequency.
I cascaded a 20Hz 2nd order highpass filter with a peaked boost of 6dB, Q = 2 ~33Hz
to get the assistance filter like EV did in their innovative 1970's "Interface" series.
Its pretty flat to 30HZ that way.
you can see that around 50Hz, excursion is at a maximum and limited
to about 60 watts input at that frequency.
I cascaded a 20Hz 2nd order highpass filter with a peaked boost of 6dB, Q = 2 ~33Hz
to get the assistance filter like EV did in their innovative 1970's "Interface" series.
Its pretty flat to 30HZ that way.
An externally hosted image should be here but it was not working when we last tested it.
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Tjj226, If high frequency response approaching 20kHz is an important goal, review HTM-12 at DIYsoundgroup
Denovo Audio HTM-12
diysoundgroup uses the SEOS-15 which has excellent polar control and uses a 1" compression driver for >18kHz extenstion, combined with the 12" Eminence 2512_II MidWoofer. Efficient low frequency bass requires a large volume ported cabinet ~5cuft, but with diy you can build a shape which fits your room. A wide cabinet lowers the baffle step frequency, but a 48"-54" tall cabinet might better match HT appearance.
Look, up in the sky!
Is it a bird?
Is it a plane?
NO, it's super-tall woofer cabinet.
Denovo Audio HTM-12
diysoundgroup uses the SEOS-15 which has excellent polar control and uses a 1" compression driver for >18kHz extenstion, combined with the 12" Eminence 2512_II MidWoofer. Efficient low frequency bass requires a large volume ported cabinet ~5cuft, but with diy you can build a shape which fits your room. A wide cabinet lowers the baffle step frequency, but a 48"-54" tall cabinet might better match HT appearance.
Look, up in the sky!
Is it a bird?
Is it a plane?
NO, it's super-tall woofer cabinet.
Attachments
Tjj226, If high frequency response approaching 20kHz is an important goal, review HTM-12 at DIYsoundgroup
Denovo Audio HTM-12
diysoundgroup uses the SEOS-15 which has excellent polar control and uses a 1" compression driver for >18kHz extenstion, combined with the 12" Eminence 2512_II MidWoofer. Efficient low frequency bass requires a large volume ported cabinet ~5cuft, but with diy you can build a shape which fits your room. A wide cabinet lowers the baffle step frequency, but a 48"-54" tall cabinet might better match HT appearance.
Look, up in the sky!
Is it a bird?
Is it a plane?
NO, it's super-tall woofer cabinet.
I have heard their stuff before. It wasn't my cup of tea. A crap ton of bass, and a lot of screechy highs left the mids to fend for themselves.
They are cheap enough where I might pick up a pair and experiment with crossovers or dampening though.
As far as overall frequency bandwidth goes, I have a pair of snell J3s which claim to go from 50hz to 20K. Now I am still fairly young compared to most people in the audio community, so I can hear up to around 19khz with headphones. But I can't hear above 15khz on my speakers. I am honestly not even sure if my tweeters are working properly lol.
But some of my favorite systems that I have listened to go from 30hz to about 16.5K and thats about what I am aiming for or better. Even the altec 414 at 40hz would be fine with me honestly. I mostly listen to classic rock, female vocals, and a very select few modern music bands such as daft punk, MGMT, and Justice.
If I can faithfully reproduce a double bass, and have enough bandwidth up top to be able to reproduce drum cymbals, I think I will be in pretty good shape. God only know what sort of frequency cut off my 300b amp will have, so thats another factor
Thank you for the time, Freddi. So if I'm understanding this, the 20hz high pass is to block the lowest tones from the woofer to protect from over excursion, and to keep it cleaner down low? Is that high pass just an added filter to the existing woofer crossover? Also, based on the max excursion at 60watts input at 50 hz, based on an spl calc that I looked at, I came up with 115 db at 30hz, assuming flat response. I may be way off, as I'm learning as I go. I may not even need that low of an extension. Am I close to understanding? I have listened to Klipschorns with 40 watts driving them, and that was a tingle inducing experience. Glenn.here's a siim 4th and 6th order bass reflex 151 liters , fb ~33Hz
you can see that around 50Hz, excursion is at a maximum and limited
to about 60 watts input at that frequency.
I cascaded a 20Hz 2nd order highpass filter with a peaked boost of 6dB, Q = 2 ~33Hz
to get the assistance filter like EV did in their innovative 1970's "Interface" series.
Its pretty flat to 30HZ that way.
Out of curiosity: how did you do the 19kHz check? Through a browser + sound card?
Often these have issues or 'ghost' tones present which make these tests invalid. I can easily 'hear' up to 20kHz with some files.
Can you pass this 19kHz blind test?
Blind Testing a 19 kHz Upper Hearing Limit
How low do you have to go before passing is easy?
Daft Punk's Debut album: 1997
I liked this when it was released, so I can't call myself young
A couple years ago, my hearing was tested (in a well-equipped hospital) as ~10dB down at 8kHz, which is decent. 8kHz is as high at the normal tests go, cos above that is irrelevant for intelligibility / health.
Today*, the highest thing I can clearly hear as a tone is 17kHz, but my threshold for detecting it is very poor (an 8kHz tone at the same setting seems MUCH louder), so I consider this only academically interesting, and irrelevant for music.
...thus I don't really care whether a speaker goes past 15kHz.
* recently it was 18kHz. It can vary a bit, day-to-day, depending on hayfever, how caffeinated / alert I am, etc.
Your post reminded me on why early Altec theater speakers which use a crossover from the woofers to a large midrange horn at around 600Hz-700Hz and going up to 10Khz, are so well reviewed and still favored. Dr. Griesinger's research demonstrated that 700-7000Hz is the critical range of frequencies where our hearing and our brain combine the fundamental sound with its harmonics. According to Griesinger, we detect pitch more on the higher harmonics than we do on the fundamental. One of the main benefits of using a 1.4" compression driver on a constant directivity horn is to cover the critical 700-7000Hz, and then accept the best extension near 20kHz as possible.
The BMS coaxial compression drivers also select a 600-7000Hz crossover.
"The patented design of the coaxial BMS 4594 is a result of extensive dedicated research and development providing dramatic improvement in response, clarity and ansparency. The BMS annular midrange diaphragm covers the frequency range between 300 and 7.000 Hz with a smooth, linear response. The large diaphragm excursion of max. +/-0.8 mm results in high output and increased power handling up to 1.300 W peak. The ultra light annular diaphragm for the high range offers exceptional transient response with very high efficiency from 6 to 22 kHz. The unique voice coil technology employs a light weight Copper clad Aluminum wire wound inside and outside of the Kapton™ former to improve the heat dissipation, dramatically increasing the acoustic output and reliability of the driver while minimizes the power compression. The use of high grade Neodymium magnets provide improved performance while significantly reducing transducer weight."
Newer 1.4" horns have become difficult to find (SEOS_24, JMLC-350, eJMLC-300) and so a BMS coaxial build is hard to recommend.
The BMS coaxial compression drivers also select a 600-7000Hz crossover.
"The patented design of the coaxial BMS 4594 is a result of extensive dedicated research and development providing dramatic improvement in response, clarity and ansparency. The BMS annular midrange diaphragm covers the frequency range between 300 and 7.000 Hz with a smooth, linear response. The large diaphragm excursion of max. +/-0.8 mm results in high output and increased power handling up to 1.300 W peak. The ultra light annular diaphragm for the high range offers exceptional transient response with very high efficiency from 6 to 22 kHz. The unique voice coil technology employs a light weight Copper clad Aluminum wire wound inside and outside of the Kapton™ former to improve the heat dissipation, dramatically increasing the acoustic output and reliability of the driver while minimizes the power compression. The use of high grade Neodymium magnets provide improved performance while significantly reducing transducer weight."
Newer 1.4" horns have become difficult to find (SEOS_24, JMLC-350, eJMLC-300) and so a BMS coaxial build is hard to recommend.
I'm currently excited about using a 2" fullranger on a horn for this ...have tried it covering 500Hz and up, but may lift the XO to 600 or 700Hz.
? lots of people seem to like the xt1464, e.g.
a new waveguide to try: 18Sound XT1464 | MiniRIG
No-name versions (Faital clones?) are available for the princely sum of $30.
(444) 9" x 14"Oval 1.5" or 1 1/2" Bolt-On Horn For Many 1.5" or 1.4" Exit Driver 647356199929 | eBay
Out of curiosity: how did you do the 19kHz check? Through a browser + sound card?
Often these have issues or 'ghost' tones present which make these tests invalid. I can easily 'hear' up to 20kHz with some files.
Can you pass this 19kHz blind test?
Blind Testing a 19 kHz Upper Hearing Limit
How low do you have to go before passing is easy?
Daft Punk's Debut album: 1997
I liked this when it was released, so I can't call myself young
A couple years ago, my hearing was tested (in a well-equipped hospital) as ~10dB down at 8kHz, which is decent. 8kHz is as high at the normal tests go, cos above that is irrelevant for intelligibility / health.
Today*, the highest thing I can clearly hear as a tone is 17kHz, but my threshold for detecting it is very poor (an 8kHz tone at the same setting seems MUCH louder), so I consider this only academically interesting, and irrelevant for music.
...thus I don't really care whether a speaker goes past 15kHz.
* recently it was 18kHz. It can vary a bit, day-to-day, depending on hayfever, how caffeinated / alert I am, etc.
I did that test. 17khz I could hear well enough. 18 was iffy at best. 19 was just not possible.
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