Hello all,
I'm after some ideas please. Some time ago I sold my last speaker setup - 2 x xls10s in sealed boxes and a pair of sealed mtm speakers. The mtm speakers were made with 8 inch midbasses and 1.25 inch SB Acoustics tweeters crossed over at 1kHz.
I would like to do things differently this time. Just not sure how...
The original system was fully active (3way) with a low cost DSP. Still got the DACs and DSP and homemade / designed 4 channel amp. Would like to re-use these.
Have 2 x Dayton Audio RSS390he drivers and a QSC RMX4050 amplifier towards the new system already.
Not really limited when it comes to cabinet size. The room is 21ft long. Would like to be able to listen to organ music properly so need decent low end. No aversion to professional drivers. Need to keep cost reasonable.
One limitation of the original system was the listening sweet spot. It was about the width of my head.
The new setup needs to be an all rounder.
Any thoughts would be very much appreciated.
Thanks,
Paul
I'm after some ideas please. Some time ago I sold my last speaker setup - 2 x xls10s in sealed boxes and a pair of sealed mtm speakers. The mtm speakers were made with 8 inch midbasses and 1.25 inch SB Acoustics tweeters crossed over at 1kHz.
I would like to do things differently this time. Just not sure how...
The original system was fully active (3way) with a low cost DSP. Still got the DACs and DSP and homemade / designed 4 channel amp. Would like to re-use these.
Have 2 x Dayton Audio RSS390he drivers and a QSC RMX4050 amplifier towards the new system already.
Not really limited when it comes to cabinet size. The room is 21ft long. Would like to be able to listen to organ music properly so need decent low end. No aversion to professional drivers. Need to keep cost reasonable.
One limitation of the original system was the listening sweet spot. It was about the width of my head.
The new setup needs to be an all rounder.
Any thoughts would be very much appreciated.
Thanks,
Paul
Was the 1.25 inch in a waveguide or something else that restricted its dispersion? Or was the MTM configuration something abnormal? With those size drivers and that cross point, it doesn't seem like you should have had such a narrow sweet spot.
A 1.25 inch may be more directional in the top octave than smaller tweeters - was that what you meant?
Or maybe you didn't like the narrower vertical dispersion of a typical MTM?
A little more detail about what exactly you had going on and what you didn't like would help people make better suggestions.
A 1.25 inch may be more directional in the top octave than smaller tweeters - was that what you meant?
Or maybe you didn't like the narrower vertical dispersion of a typical MTM?
A little more detail about what exactly you had going on and what you didn't like would help people make better suggestions.
Hi mattstat,
The tweeters were ring radiators.
Sb29rdac
I think the tweeters were too big for good directivity. Had to sit in the perfect position and not move. Then the sound was good with a good sound stage. The sound balance was good but it got shouty when turned up.
I'm not against doing another mtm. Think the drivers were too big and the crossover point too low.
And I think that while the last system was my best attempt yet. My limited knowledge led to, what I feel, were compromises on top of compromises. For example, the xls10s couldn't really keep up with the mtm mains.
This time I would like to get things more optimal. I have lots of questions and have done lots of reading but my head now spins...
The tweeters were ring radiators.
Sb29rdac
I think the tweeters were too big for good directivity. Had to sit in the perfect position and not move. Then the sound was good with a good sound stage. The sound balance was good but it got shouty when turned up.
I'm not against doing another mtm. Think the drivers were too big and the crossover point too low.
And I think that while the last system was my best attempt yet. My limited knowledge led to, what I feel, were compromises on top of compromises. For example, the xls10s couldn't really keep up with the mtm mains.
This time I would like to get things more optimal. I have lots of questions and have done lots of reading but my head now spins...
I too listen to organ music, also the 26 hz notes of piano. I play both instruments, so I have heard the real thing. I have a pair of speakers that have - 6 db response 45 degrees off axis and +15 -30 deg off horizontal. They are mounted on poles 2 m high. I can walk anywhere in my 3.5 m wide x 8 m long room and the sound is the same, over 1.5 m away from boxes. There is a lot of furniture, media storage, instruments, to break up standing waves.
They have a -3 db point of 54 hz but are 10 db down at 40. With them backed into a hard plaster wall for a 6 db boost, organ bass is quite realistic. I am not motivated to buy/build a sub channel with a 2nd amplifier. The HD is 2nd and 3rd harmonic down 25 db down from 5 w music 60-12khz.
They are Peavey SP2(2004) with a 15" 1508-KADT woofer and a RX22 1" CD. They sound as good on rock & pop music as classical. However nothing stresses a pair of drivers like reproducing a Steinway grand piano. My test track has such a source, and I have a Steinway console piano for calibration of what a speaker is supposed to sound like. My ears respond to 14 khz at age 74.
As SP2 have been stolen once, and have substantial pawnshop value, I am building a pair of ugly copies. Woofer is Eminence Deltapro-15a and tweeter is N314T-8. Horn is Eminence HS14. Crossover if finally passive will be external on the floor. Crossover prototyping will be via graphic equalizer.
Wishing to keep the lift weight under 50 lb, I wish I had bought Eminence Kappapro-15A as the VAS is much smaller than the delta. I am going to set the tweeter+horn in niches on top of the case to reduce the lift weight.
I intend to crossover at ~1400 hz. 1000 is doable with the higher watt rating of the N314T versus the RX22. Watt rating makes the SP2(2004) cross at 1800 hz for 500 w pink noise maximum. To get the dispersion wide Peavey built the cases as wedges, which is difficult for an amateur to reproduce.
Happy designing and later building.
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Use a full range driver in open baffle. Cross at 5-7k to an AMT (potentially a dipole) and a 15" driver facing the floor, slot loaded with sealed back chanber crossed at between 80 - 200Hz, depending on where the full range (in reality mid driver) needs it.
Use DSP to figure out the crossover frequencies, see if things work out nicely with 1st order filters. If that works you can think about a serial crossover.
That may have been the tweeter crossing so low, as you noted. Most dome/ring tweeters have rising distortion below about 2 kHz (best case) even if they have very low resonance. You can also be limited by volume displacement with such a small diaphragm, so you may have been out of excursion on the tweeter if you were pushing the SPL up. At Xmax that tweeter should do about 96 dB at 1 kHz at 1 meter, but how cleanly it does it is hard to estimate. It's one of those things you have to test with your crossover to know when you're stretching things like that. Having a better idea about the SPL you want to achieve at what distance would be helpful also.
Here's the distortion plot from Zaph's Tweeter Mishmash test of the SB29RDC, which was run at an equivalent of 90dB at 1 meter. I'm assuming it's basically the same performance as the SB29RDAC.
www.zaphaudio.com/tweetermishmash/
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Imaging problems, shouty when loud... I can't tell without seeing pictures but what did you do to manage directivity and diffraction?
But Voice of the Theater used are $$$$$. I heard some at a cinema in 1967 on recommendation of the H.S. band director. I was very impressed.
Copies Peavey SP(2004) I bought for $200 each. 98 db 1w1m efficient. See post #4 for dispersion.
I had Peavey SP2-XT previous, stolen. Similar specs only 300 w AES power handling instead of 500w, -6 db horizontal dispersion 85 deg 500-16000 hz, instead of 45 deg. sensitivity 101 db 1w1m. I bought these for $300 ea.
SP2G, 300 watt handling, 3 db low point 65 hz instead of 54 hz.
More money saved if you buy blown road warriors. The Peavey drivers are still in production.
Or build copies as I am doing with the uglison in post #4. Eminence drivers are local to me, factory is 30 miles away. Cutting glueing wood is my weak point.
http://web.archive.org/web/20081123...om/Archives/Digests/199911/1999.11.05.03.html
http://web.archive.org/web/20040808135309/http://www.mmdigest.com/Tech/isingform.html
https://www.google.com/search?q=pip...ome..69i57.17831j0j4&sourceid=chrome&ie=UTF-8
http://www.rwgiangiulio.com/math/pipelength.htm
https://www.allenorgan.com/products/speakers/speakers.html
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I would do a more controlled dispertion in a wider range for that. Compression driver in a wide horn with a bigger woofer as midbass could be a thing. You don't have to play them as loud as they go for good sound, but when done right it will have a wider listening spot. Altec is the classic example, but a good system can be build for far less money and taken space with modern components. It can be 2 way to combine them with your subs, it can (and is often best) active with the dsp and amps you have. Like that you don't need a driver that goes very low, flat to about 80Hz is enough.
The advantage is that horns with compression drivers often have a smaller but more controlled dispertion for the tweeter, while dome tweeters start beaming at a certain point, even in a waveguide. And with bigger drivers you can play louders with less distortion on low volumes.
Examples of build are all over the place, from the econowave projects, over the Humble Calpamos to Pii speakers and some of Troels builds. I would use a 8 to 12" midbass coupled to a good 1.4" compression driver in a constant directivity horn and cross it where both drivers best fit and make your woofer go to 80Hz flat, preferable in a sealed enclosure (but ported is not a disaster) and use your dsp as active crossover between the tweeter, the midbass and the subs.
The advantage is that horns with compression drivers often have a smaller but more controlled dispertion for the tweeter, while dome tweeters start beaming at a certain point, even in a waveguide. And with bigger drivers you can play louders with less distortion on low volumes.
Examples of build are all over the place, from the econowave projects, over the Humble Calpamos to Pii speakers and some of Troels builds. I would use a 8 to 12" midbass coupled to a good 1.4" compression driver in a constant directivity horn and cross it where both drivers best fit and make your woofer go to 80Hz flat, preferable in a sealed enclosure (but ported is not a disaster) and use your dsp as active crossover between the tweeter, the midbass and the subs.
AllenB,
In a short, nothing was done about diffraction and directivity. All enclosures were sealed, braced, lead lined and heavily stuffed with no rounding on edges of baffle.
When I built the last setup I was more into the electronics side of things. Finding out about Rew, DSPs and room curves etc was such an advancement for me that the idea of proper speaker design was pushed aside. Now I want to use the electronics as a "polish" for an already good speaker setup.
Indianajo,
Seems counterintuitive with my limited understanding to cross a 15 inch speaker at 1.4 khz. How is the dispersion at those frequencies? If 15 inch speakers can be crossed that high then that opens up options for the top end. My subs will be stereo. Or are they not really subs but just woofers... 😉
I do like the idea of compression drivers or at least avoiding a plain dome tweeter. For no other reason that "I've always had domes"
Then we have schiirrn's idea with the fullrange mid open baffle and an amt crossed at 5-7 kHz. Tweeter assisted full range. Simple to make but probably difficult to get right. Need to learn a bit more about Amts.
For some reason, I quite like waxxs idea of using a larger mid 8-12 inch. Using a larger mid but not pushing it has it's advantages. My gut feeling is that the sound would be relaxed. But I also like the high crossover frequency of using a fullrange as a mid.
GM,
Thank you for the references. The organ speakers were interesting. Passive radiators or vented tuned low along with response graphs... Useful stuff. Still have to read the two threads. Vented speakers being resonators naturally match organs.
Mattstat,
You are probably right. I was pushing the tweeters quite hard. Was using third order as the measured roll off of the tweeter summed with this to make 4th order.
Erik,
Horns are an option. I just don't know much about them yet. I have much reading to do.
Thank you to everyone for their replies. Really appreciate the time taken to help me 🙂
Paul
In a short, nothing was done about diffraction and directivity. All enclosures were sealed, braced, lead lined and heavily stuffed with no rounding on edges of baffle.
When I built the last setup I was more into the electronics side of things. Finding out about Rew, DSPs and room curves etc was such an advancement for me that the idea of proper speaker design was pushed aside. Now I want to use the electronics as a "polish" for an already good speaker setup.
Indianajo,
Seems counterintuitive with my limited understanding to cross a 15 inch speaker at 1.4 khz. How is the dispersion at those frequencies? If 15 inch speakers can be crossed that high then that opens up options for the top end. My subs will be stereo. Or are they not really subs but just woofers... 😉
I do like the idea of compression drivers or at least avoiding a plain dome tweeter. For no other reason that "I've always had domes"
Then we have schiirrn's idea with the fullrange mid open baffle and an amt crossed at 5-7 kHz. Tweeter assisted full range. Simple to make but probably difficult to get right. Need to learn a bit more about Amts.
For some reason, I quite like waxxs idea of using a larger mid 8-12 inch. Using a larger mid but not pushing it has it's advantages. My gut feeling is that the sound would be relaxed. But I also like the high crossover frequency of using a fullrange as a mid.
GM,
Thank you for the references. The organ speakers were interesting. Passive radiators or vented tuned low along with response graphs... Useful stuff. Still have to read the two threads. Vented speakers being resonators naturally match organs.
Mattstat,
You are probably right. I was pushing the tweeters quite hard. Was using third order as the measured roll off of the tweeter summed with this to make 4th order.
Erik,
Horns are an option. I just don't know much about them yet. I have much reading to do.
Thank you to everyone for their replies. Really appreciate the time taken to help me 🙂
Paul
As stated in post 4 SP2(2004) response is 6 db down over 45 deg from axis, and +15 -30 deg from horizontal. 54-17500 hz. Made to mount high over crowd heads. Crossover is 1800 hz. SP2-XT -6 db response was specified 85 deg 500-16000 hz. See datasheet for polar charts of response, - 3 db +-22.5 deg hori. SP2-XT crossover is 1200 hz. SP2(2004) had wedge shaped case. It is full of folded elastomer sheet. SP2-XT was parallelepiped. So forget all that blather on the internet about beaming. Engineering can overcome that. I am going to try to reproduce the wedge shaped case for the uglyson. Reduced standing waves side to side. Advantage of a 15" woofer, it hardly moves at house volume, leading to the specified low HD at 5 watts. I typically listen at 1/8 to 2 watts. 1812 overture cannon is higher watts. I did a 50 watt check of an amp using Rhiannon Shut up & Drive, and had to wear earplugs to avoid damage. I auditioned a SP5 with 12" woofer before I heard the SP2 on the sales floor. In the middle of an open room, the piano bass was unconvincing on opening of Appassionata sonata.
GM post about 16 hz pipes not pertinent. 16 hz cannot be heard as a tone, only as a sound effect. IMHO. No pipe organ in this tiny city of 2000000 has a 64' rank. St Martins has a 32' pipe rank, St Bartholomew has a speaker for the 32' rank. I hear 26 hz A0 as a tone.
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Indianajo,
16Hz does match up well with the LLT subwoofer tuned to 17Hz like the Marty though.
Christmas 1997 Coventry Cathedral. That was when I first appreciated the organ. A low note was used as a prelude to songs (well carols). I loved the effect. Looked up the spec of the Harrison and Harrison there. 32ft is the longest pipe...
Yeah, my knowledge of speakers is lacking. Suppose it is much like amplifier design and the myths surrounding that - eventually found my way and decided boutique parts were a waste of money. It was the engineering and build that mattered not the specific components.
I want to do a proper job this time with every compromise understood.
Ear plugs to avoid hearing damage at 50w. I can see the advantages to that... I have about 130w/ch available for whatever creation I end up doing.
What's your take on the crossover frequency choice? Is it a case that it ALL depends on drivers used? And it's about correct implementation not about avoiding or aiming for particular frequencies.
16Hz does match up well with the LLT subwoofer tuned to 17Hz like the Marty though.
Christmas 1997 Coventry Cathedral. That was when I first appreciated the organ. A low note was used as a prelude to songs (well carols). I loved the effect. Looked up the spec of the Harrison and Harrison there. 32ft is the longest pipe...
Yeah, my knowledge of speakers is lacking. Suppose it is much like amplifier design and the myths surrounding that - eventually found my way and decided boutique parts were a waste of money. It was the engineering and build that mattered not the specific components.
I want to do a proper job this time with every compromise understood.
Ear plugs to avoid hearing damage at 50w. I can see the advantages to that... I have about 130w/ch available for whatever creation I end up doing.
What's your take on the crossover frequency choice? Is it a case that it ALL depends on drivers used? And it's about correct implementation not about avoiding or aiming for particular frequencies.
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Well, not necessarily saying you should do exactly that, but a high efficiency 2-way could be doable.
A high efficiency 2-way is very doable. You can see mine here: https://www.diyaudio.com/community/...ig-horn-loaded-2-way-using-what-i-had.420977/
These drivers are pretty much unobtainable now, but you can do something similar with a JBL 2226 (15" driver) and your choice of large-ish voice coil 1" CDs (like the Radian 475 or Peerless DFM-2544R00, among others) with a waveguide about as wide as the mid-woofer (so directivity can match at the crossover point). Of course, you end up with a big cabinet. But there's not much you can do about that. If you scale it down - say a 10" mid-woofer and a smaller waveguide in a smaller cabinet - that would work too. But your bass extension would suffer. That might be OK if you've got subs, and your room has some gain at low frequencies. I almost went that route (with a B&C 10CL51) as they would fit my room better (it's not a huge room). But I had these drivers in my stash and some old cabinets as well. So, I went with that.
I think that one of the keys in making this easy is going with an active crossover with DSP. Inductors have gotten so expensive, and DSP has gotten cheaper. Plus, amps are pretty cheap too. There really isn't a cost argument for passive crossover anymore (not for DIY guys, at least). I don't see ever going passive again.
These drivers are pretty much unobtainable now, but you can do something similar with a JBL 2226 (15" driver) and your choice of large-ish voice coil 1" CDs (like the Radian 475 or Peerless DFM-2544R00, among others) with a waveguide about as wide as the mid-woofer (so directivity can match at the crossover point). Of course, you end up with a big cabinet. But there's not much you can do about that. If you scale it down - say a 10" mid-woofer and a smaller waveguide in a smaller cabinet - that would work too. But your bass extension would suffer. That might be OK if you've got subs, and your room has some gain at low frequencies. I almost went that route (with a B&C 10CL51) as they would fit my room better (it's not a huge room). But I had these drivers in my stash and some old cabinets as well. So, I went with that.
I think that one of the keys in making this easy is going with an active crossover with DSP. Inductors have gotten so expensive, and DSP has gotten cheaper. Plus, amps are pretty cheap too. There really isn't a cost argument for passive crossover anymore (not for DIY guys, at least). I don't see ever going passive again.
Have you looked at mabat's ATH horn thread? Even a properly selected 1" compression driver in one of his horn's can be used down well below 1 kHz, making a crossover to a high-efficiency 15" driver quite reasonable, and with good directivity matching. Since you have good subs available, the 15 could use a sealed enclosure (easy to build, small, no midrange leakage or port resonances to deal with). 'm headed that direction myself for my next big project.
My current system is closer to schiirn's suggestion, an ESS Heil dipole AMT, an 8" OB midrange, 15" midbass, and subs. I like it a lot, the horn system will be for something different. I also have the parts for a small 2-way monitor "point-source" system to use with the same subs. Don't know which I will like best in the end, so gotta try 'em all!
Bill
I want to stay well away from cone breakup of a woofer, and away from large excursions of a CD diaphragm. The products available now, that is pretty easy. With 2 graphic equalizer channels & 2 amp channels I can tune to what measures best or is most pleasing, then later try to duplicate with inductors capacitors & resistors.
Peavey used same 2 drivers 1985 SP2, 1995 SP2-XT, 2004 SP2. Crossovers 800 hz, 1200 hz, 1800 hz. Watt ratings 175, 300, 500. They had to cross so high 2004 because the RX22 CD would not take more than 70 watts and they wanted a 500 watt AES rating to sell more product. Pink noise result determined crossover point. Then they did a lot of cabinet engineering to get the dispersion wide enough.
My Deltapro-15a woofer has a response rise beginning at 1000 with a little peak at 2000. No jagged hills & valleys at cone breakup. I'm aiming to tame the response rise with one inductor centered about 1200. The N314T CD is useable to 800, but 3 db fall from 1500 to 1000 and another 3 db down at 800. Figure if I do 12 db/octave cut (inductor + capacitor) at about 1200 would make a nice flat sum between the two drivers.
I aim to reduce the high cost of inductors by attempting to wind myself out of surplus wire. 120' of PFTE 14 ga was $66. Should be about 1.28 mH. According to David Weems book. I will measure inductance as excited by my Hammond organ, measuring phase shift current to voltage with 2 channel scope. Lower inductance values could be 100' rolls of PVC wire from the auto supply. About right diameter in the package. Peel off turns to match measured inductance. However, a 2 channel graphic equalizer like a Peavey 215 is about $80 with freight. Another 2 channel amp is about $80. Cheaper than 4 janzen inductors + 2 MKP caps. Main disadvantage to electric setup over passive crossover is the electricity to run 2 amps 12 hours a day. I listen to the FM that much some days.
I like the sound of 32' pipes. I think 64' pipes are silly, right along with earthquake effects in cinemas. I worked in geophysics 1974-1978 and I heard 1000 horsepower sweeps from 1/2 hz to 25 hz. They shook the ground with hydraulic cylinders on a pad under a 6000 lb vehicle with CAT diesel power. Interesting, but not music.
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Running it that low, with high SPL looking at the measurements i linked. the distortion is relatively high below 2k, even at 1 watt.
Did you try to notch the FS impedance peak at 6-700hz, to see if there was a improvement.
https://hificompass.com/en/speakers/measurements/sbacoustics/sb-acoustics-sb29rdac-c000-4
https://www.diy-hifi-forum.eu/forum...6c03c8b6e3e2161e3249170ed24&p=90514#post90514
Did you try to notch the FS impedance peak at 6-700hz, to see if there was a improvement.
https://hificompass.com/en/speakers/measurements/sbacoustics/sb-acoustics-sb29rdac-c000-4
https://www.diy-hifi-forum.eu/forum...6c03c8b6e3e2161e3249170ed24&p=90514#post90514
Nobody builds the perfect speaker in one go 😉
My question was a rhetorical one. You'll find there's a limit to what you can do electronically. You can EQ a speaker perfectly flat, but that won't fix the fundamental character flaws which are due to acoustic problems.