I was hoping to share my plan for a tower speaker with the far more technical experts on these forums, which i thought up by reading them. The inspiration was a not so worthy speaker i once had, an advent prodigy tower, 1" soft dome and 8" woofer. I really enjoyed the bass and guitar, and assume th 8" drive doing most of that work, and it being sealed, rather than maybe it being split betweeen speakers on a 3 way, were major contributing factors. I saw online the crossover was 3khz, that seems extreme though. So my goal is a 2 way tower with an 8" sealed woofer, and maybe a tweeter with a bit of low end reach to help it out. I thought about either a tweeter or a 3 or 2" full range. currently i like the looks of a dayton rs225-8 woofer and an sb acoustics sb29rdc ring dome tweeter, although i havent yet heard such a tweeter in person. I currently have a gfa-2535 4 channel, perhaps have the lower effeciency woofers on noisy channels? And an analog 24db/oct ashley xr-1001, which means sensitivity matching isnt a concern, correct? I have questions about the cabinet itself, but i would like to see if i am on the right track first. How how this cross over might work out for this, if it will. More wattage would probably be good for the woofer, but i am hopeful i can use what i have for a decent set up in the end. Does any apparent problem jump out? Non addressable ones?
Why not make use of the tower length to create, say, a mass loaded transmission line (MLTL) speaker? Lower bass cutoff than sealed and not a lot more trouble than a bass reflex box.
Another possibility if you want more weight (power handling and sensitivity) in the bass/mid region is to use two RS 225-8 and either mount both drivers facing forward or possibly a bipole pair (one facing front and the second firing backward on the rear panel.)
Take a look at the frequency response of the RS 225-8 and decide if you can stand a 3 kHz cross or if you have concerns about the break-ups (peaks and valleys) in the upper frequency response due to the Al cone performance. A 2 KHz cross with a high slope crossover will prevent any issues from the RS225-8. Also consider a small diameter dome or a full frequency range mid/tweeter as you suggest.
Another possibility if you want more weight (power handling and sensitivity) in the bass/mid region is to use two RS 225-8 and either mount both drivers facing forward or possibly a bipole pair (one facing front and the second firing backward on the rear panel.)
Take a look at the frequency response of the RS 225-8 and decide if you can stand a 3 kHz cross or if you have concerns about the break-ups (peaks and valleys) in the upper frequency response due to the Al cone performance. A 2 KHz cross with a high slope crossover will prevent any issues from the RS225-8. Also consider a small diameter dome or a full frequency range mid/tweeter as you suggest.
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I was frankly unsure of how that sort of speaker actually sounds, and how tough to make it would be. I was simply thinking, since sealed is how the typical mid range is set up, it would be advantageous for a midwoofer as well, if proper output could still be managed? I do how ever understand making the speaker more effecient can reduce distortion. Would i look for a different woofer for a loaded transmission line design? I picked that one specifically for being perhaps good in a sealed cabinet. And i indeed had a 1.6-2khz cross over in mind. I also think i might want the speaker to be very placement indifferent, at least for a speaker. It can end up moving around between houses. That excludes a dipole i think, what about transmission line?
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SB_Acoustics has an 8" woofer SB23NACS45- 4/8 with a ribbed aluminum cone which pushes the main cone breakup to 4kHz.
--SEALED 1.4cuft box produces -F3 =45Hz
--PORTED 2.5cuft box produces -F3 = 26Hz
Wavecor has a 30 mm textile tweeter with waveguide TW030WA-11/12 which is designed for low frequency crossovers.
These are modest cost drivers($94 + $80), Your Bi-Amp saves the cost of passive crossover parts.
Based upon your amplifier power, you can select 4-ohm or 8-ohm drivers.
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An LR4/ LR4 crossover around 1,200Hz can produce a smooth controlled directivity polar response.
--Does your analog 24db/oct ashley xr-1001 include time delay to remove the difference in tweeter vs. woofer voice coil offset?
--Does your ashley xr-1001 provide bass equalization? Linkwitz Transform? Bass equalization?
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To reduce lobing, the tweeter should be butted to the woofer.
To reduce cabinet edge diffraction distortion, the tweeter baffle section should have beveled or round edge treatment.
---On a simple box construction, a modest off-center tweeter placement will reduce edge diffraction distortion.(spreads the energy over diverse angles)
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A tall MLTL (mass loaded transmission line) can deliver smooth, deep bass, and a bottom port will help reduce high frequency port leakage.
---Seated ear level is ~36" - 39", so a 42" - 45" high cabinet could be used.
--SEALED 1.4cuft box produces -F3 =45Hz
--PORTED 2.5cuft box produces -F3 = 26Hz
Wavecor has a 30 mm textile tweeter with waveguide TW030WA-11/12 which is designed for low frequency crossovers.
These are modest cost drivers($94 + $80), Your Bi-Amp saves the cost of passive crossover parts.
Based upon your amplifier power, you can select 4-ohm or 8-ohm drivers.
=========
An LR4/ LR4 crossover around 1,200Hz can produce a smooth controlled directivity polar response.
--Does your analog 24db/oct ashley xr-1001 include time delay to remove the difference in tweeter vs. woofer voice coil offset?
--Does your ashley xr-1001 provide bass equalization? Linkwitz Transform? Bass equalization?
=========
To reduce lobing, the tweeter should be butted to the woofer.
To reduce cabinet edge diffraction distortion, the tweeter baffle section should have beveled or round edge treatment.
---On a simple box construction, a modest off-center tweeter placement will reduce edge diffraction distortion.(spreads the energy over diverse angles)
========
A tall MLTL (mass loaded transmission line) can deliver smooth, deep bass, and a bottom port will help reduce high frequency port leakage.
---Seated ear level is ~36" - 39", so a 42" - 45" high cabinet could be used.
The xr-1001 offers response tuning in reference to the cross over, which may be what you mean by linkwitz transform. It offers volume control for each output, if that counts as bass equalization, but it can not tune the bass independently of the higher frequencies a given driver receives. I don't believe it offers time delay, either
Does butted refer to the distance between woofer and tweeter? And/or orientation/location
Does butted refer to the distance between woofer and tweeter? And/or orientation/location
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The RS225-8 works really well in an ML-TL 2-way with an appropriate tweeter and a high-order crossover. That's exactly what I built in the RS duet several years ago. The tweeter was the Dayton RS28F which is no longer available, but with a high-order crossover there should be a number of tweeters that would be a good match.
Paul
p.s. The modeled f3 for the RS duet was 32 Hz. The crossover corner was 1400 Hz and had quasi-8th-order rolloffs for both woofer and tweeter. If you'd like to have my write-up on this design, send me a private message with your direct email address.
Paul
p.s. The modeled f3 for the RS duet was 32 Hz. The crossover corner was 1400 Hz and had quasi-8th-order rolloffs for both woofer and tweeter. If you'd like to have my write-up on this design, send me a private message with your direct email address.
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I would suggest to modify the existing design into a 3 way with a passive xo for the mid/tw, and an active one for the w/mid. There is plenty of space between tweeter and woofer to squeeze a midrange in between. A new surround for the woofer and the potential for a nice sounding speaker is there. The problem is as usual the same, how to integrate a crossover to work with the rest of the drivers. Without measurements it will not be a grand success.
I read the ashley xr-1001 2-way crossover manual ... it does not provide bass boost(LinkwitzTransform) or bass equalization, just LR4/LR4 crossover. These are both well behaved drivers and should perform well bi-amped if the cabinet is near the rear wall for modest baffle step loss. (I ran a bi-amp sim to verify)
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If you want to build a 3-way speaker (woofer, sealed midrange, tweeter) with your (four 60-watt outputs) gfa-2535, and 2-way ashley xr-1001 analog crossover, you can use a passive crossover on the tweeter+midrange for channel 1, and direct drive the woofer for channel 2, A well executed 3-way USUALLY sounds better than a well executed 2-way. If you cannot make measurements, then you can use a proven TM-passive parts crossover two way, and bi-amp to the woofer.
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If you want to build a 3-way speaker (woofer, sealed midrange, tweeter) with your (four 60-watt outputs) gfa-2535, and 2-way ashley xr-1001 analog crossover, you can use a passive crossover on the tweeter+midrange for channel 1, and direct drive the woofer for channel 2, A well executed 3-way USUALLY sounds better than a well executed 2-way. If you cannot make measurements, then you can use a proven TM-passive parts crossover two way, and bi-amp to the woofer.
Madisound - Page Not Found
The madisound page for the sb29rdc
"Flow optimized vented pole piece for optimum coupling to rear chamber"
i saw the hole in the back in a picture i saw elsewhere, as well
The madisound page for the sb29rdc
"Flow optimized vented pole piece for optimum coupling to rear chamber"
i saw the hole in the back in a picture i saw elsewhere, as well
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Attached a quick Xsim which models your 4-channel amp and basic LR4 / LR4 crossover at 1200Hz with the FRD data for the SB23NAC-4OHM woofer plus Wavecor TWO30-4ohm waveguide tweeter. Bass SPL assumes near wall speaker placement.
Download the datasheets to study how the smooth SPL over their required bandwidths supports your simple ashley xr-1001 LR4/LR4 crossover.
Download the datasheets to study how the smooth SPL over their required bandwidths supports your simple ashley xr-1001 LR4/LR4 crossover.
Attachments
Fun project. I've owned a Ashly XR-1001 xo and some SB29rdcn tweeters for a while and am very fond of both.
The SB29 is very capable of a 1.8k crossover point, even at 12 db/oct. Since the Ashly XR-1001 has 24 db/oct slopes, you're safe to run the tweets that low.
I find the SB29s very smooth and dynamic, with a flat response. Great tweet.
Just for reference, the car audio brand NVX used the SB29rdcn tweeters in one of their 2 way component sets with a 12db/oct passive crossover point of 1.5k
The SB29 is very capable of a 1.8k crossover point, even at 12 db/oct. Since the Ashly XR-1001 has 24 db/oct slopes, you're safe to run the tweets that low.
I find the SB29s very smooth and dynamic, with a flat response. Great tweet.
Just for reference, the car audio brand NVX used the SB29rdcn tweeters in one of their 2 way component sets with a 12db/oct passive crossover point of 1.5k
Are you of the general opinion than, getting the tweeter to cross over even lower to meet the woofer, rather than the woofer having to go high, is best? And perhaps even better than the average 2 way cross over frequency? As i under stand, 3 ways would probably have 8 inch woofer below 600hz? Hm. One thing i had in mind was having the woofer cover the whole guitar fundamental frequency range, which goes to 1200hz i think, which your set up does still manage. I do have an sb ring dome tweeter on the way now, at least to playnaround with. I still intend to look into your drivers though. Or MAYBE look into transmission line set ups for the woofer. But that honestly looks to be past the scope of this project of mine. Is that graph for a sealed or ported enclosure?
It is worth noting that almost every “tower” speaker will be at least partially an ML-TL — even if the designer does not know it or even if the designer is fighting it.
As Jim says, why not take full advantage.
I have found very good results using a good FR as a midTweeter — one can get the XO low enuff that much of the evil they bring goes away.
dave
Do you mean the Titan from Seas? It's an Al/Mg dome. The closest they have had to a corundum, TMK, is the Magnum magnesium dome and it's successor.
The newer corundums are from Peerless/Tymphany, TMK; DA25TX/DA32TX.
TLabs had N26 alumina/magnesia domes.
TB has 2 models with an oxidized layer on both sides of the dome; 1719/1744.
SB has the 26CDC.
Eton HD ceramics.
Visaton KE25SC.
Accutons too.
As for the Peerless corundum, it sounds great!
Wolf
1) The simulation uses the ported cabinet SPL data with modest baffle step bass reduction.
SB23NACS45-4
--SEALED 1.4cuft box produces -F3 =45Hz
--PORTED 2.5cuft box produces -F3 = 26Hz
2) The 8" SB23NACS45 starts to beam around 1kHz. Study the SPL curve. Instead of the sound pressure having a 180-degree delivery(polar response) to the listeners, the shorter wavelengths rapidly start to deliver lower SPL to listeners sitting off the 0-degree main axis. Beaming changes the ratio of direct vs. room reflected energy, which disrupts the sound stage. With the SB23NACS45-4 you will get strong bass from a 2.5cuft ported cabinet. You can easily plug the port to compare a low Qts sealed sound.
The smaller 30mm dome tweeter maintains the 180-degree polar response to 2.5kHz and then slowly and smoothly starts to slowly narrow the polar response, producing reduced wall reflection effects. The goal is smooth, controlled directivity.
3) It was mentioned that the RS Duet tower requires a crossover with 13 passive components to generate the slopes and reduce SPL bumps. You only have fixed LR4/LR4
4) Your new SD29RDC-4 1.1" dome tweeters are also a good match for the SB23NACS45-4. It will be easy for you to experiment with LR4/LR4 crossovers between 1200Hz and 1400Hz. Xsim simulation looks good at 1300Hz.
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