I'm looking at these highly regarded drivers in a U frame dipole setup with equalization (boost in the bottom octave) provided by a First-Watt B-5. They have limited area and xmax, so a single pair won't provide much output. But... for the price of a larger high quality driver, you can get 4 of these. And I don't mind cutting a few more holes.
Any thoughts?
Any thoughts?
Try 6 to 8 x 6.5in or 6 x 8in woofers in a slot loaded U-frame dipole. The bass is extremely accurate and satisfying if you can EQ it, which sound like you plan to. The woofers needn’t be fancy and the RS225 would be wasted in his application as it has reach up past 2kHz.
http://www.firstwatt.com/pdf/art_slob.pdf
I made one out of cardboard as a mock-up and it sounded very good.
Cheap and FAST OB, Literally
About the same time, Z transform made something similar independently.
http://www.firstwatt.com/pdf/art_slob.pdf
I made one out of cardboard as a mock-up and it sounded very good.
Cheap and FAST OB, Literally
About the same time, Z transform made something similar independently.
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It would help to know more about your needs
1. what type of music do you enjoy
2. how loud and how far are you from the speakers
4. whats missing with the eminence beta 15s and how many do you run per side
You should probably get REW and measure the Quads, the distortion in the bass range is probably quite high at moderate volume.
The Beta 15A has a BL²/Re of 20.92 and Mms 60g
The RS225-8 has a BL²/Re of 12.60 and Mms of 35.8g
Both drivers are basically the same strength/mass ratio but the single 15" has a 10% advantage in displacement limited output VS a pair of the RS225
I've had my eye on that design. I guess you can run the slot horizontally? Also Ripoles. One thing that is a little daunting about the slot loaded design is that you have to deal with the cavity resonance somehow.
1. Large scale classical, rock, jazz, chamber music.
2. We share a wall with another dwelling, so I don't crank it (often). Quads don't really get into the 90 Dbs anyways. About 10' from the speakers.
3. 1 woofer per side. The more you work on integrating them, the better they sound. But I assume you can do better. Quads have a very high quality of bass when properly amplified.
I don't know how the Quads measure in that respect - I'll try it. The bass sounds fantastic as far down as it goes. Have you hear them?
Does that say something about their relative sonic quality?
Is there some reason why this needs to be dipole?
Given that you are probably going to be crossing these over quite low most of the advantage that a dipole can potentially bring is lost once you are out of the rooms modal region.
You'd be far better off going for a multiple sub arrangement. Heck everyone would be better going for a multiple sub arrangement rather than anything else if bass quality is the goal. Of course this generally requires three subs and DSP + the ability to measure and EQ the subs for an even sound field.
There's nothing wrong with going for 8" drivers in a dipole just for bass but you will need a lot of them and you'll need ones that have a low resonant frequency. The RS225s aren't actually bad as far as this goes.
As you listen to
All of these have the potential for very low bass, even if you don't need it at wall shaking levels. If you are designing, paying for and building subs specifically to give you everything out of what you listen to then it would be foolish not to consider how low all of these can potentially go. The classical needs 20Hz extension if you want to do full justice to the lowest of the lowest notes. The others are less demanding although some rock can use sounds that go very low.
I guess it depends on what you want this to be able to do.
You don't need it loud, but ideally you really do need it to go low.
Given that you are probably going to be crossing these over quite low most of the advantage that a dipole can potentially bring is lost once you are out of the rooms modal region.
You'd be far better off going for a multiple sub arrangement. Heck everyone would be better going for a multiple sub arrangement rather than anything else if bass quality is the goal. Of course this generally requires three subs and DSP + the ability to measure and EQ the subs for an even sound field.
There's nothing wrong with going for 8" drivers in a dipole just for bass but you will need a lot of them and you'll need ones that have a low resonant frequency. The RS225s aren't actually bad as far as this goes.
As you listen to
All of these have the potential for very low bass, even if you don't need it at wall shaking levels. If you are designing, paying for and building subs specifically to give you everything out of what you listen to then it would be foolish not to consider how low all of these can potentially go. The classical needs 20Hz extension if you want to do full justice to the lowest of the lowest notes. The others are less demanding although some rock can use sounds that go very low.
I guess it depends on what you want this to be able to do.
You don't need it loud, but ideally you really do need it to go low.
It means that the Eminence driver is actually more capable than a pair of RS225s. Except that the RS225s have a lower fs, although not by much, which would give them the edge for low bass SPL in an open baffle.
Sonic quality in the bass is all about room integration, having enough linear volume displacement, amplifier power and did I mention room integration?
Below your rooms modal region it's all about having enough linear displacement and amplifier power as the rooms 'issues' are basically over. All you need is the ability to move air for the SPL you want to reproduce at a given frequency.
The problem is when the modes are around as these create nulls and peaks that give the illusion of lumpy bass, too much bass, or bass that isn't there at all.
Most issues of 'sound quality' and someones preferences for a specific cabinet type usually arises because one excites the modes less.
As an example, my room has a killer room mode at around 40Hz. If I have a vented speaker with flat output to 30Hz it's going to excite this mode very strongly and get annoying with music that has a bass note bang on this frequency. However if I have a sealed speaker instead, with a more shallow roll off that is flat to 60Hz, it's going to excite this mode far less whilst still having useful extension down to 30Hz.
I could say I don't like vented boxes as a result, which would be a mistake. The vented box wasn't at fault, the room was.
Dipoles are good for exciting room modes less than speakers with boxes, but they also have terrible efficiency. Multiple subs + EQ solve the room mode problem by spacing bass sources around the room. This excites the modes in an even fashion and dramatically helps to remove the dips and the 'where'd by bass go' phenomenon at certain frequencies. You then apply EQ across the subs to blend away the peaks. It's very effective but not easy to set up.
How high up do you need this to go?
Some testing I did over a decade ago suggests that's simply not true (see link below). Have you ever seen an actual test demonstrating this?
The Subwoofer DIY Page v1.1 - Projects : An INF10 Dipole Subwoofer
My impression is that the dipoles do excite room modes less. In my situation, there is a big shelf full of records behind the speakers and other, cough, damping materials (e.g. storage boxes full of crap) in the front corners. But the walls and floors are essentially concrete, so there is a lot more to be done in terms of acoustic treatments. Measurements I've done with a couple of different dipole setups I've done show a big dip around 40hz, and then it comes right back up at 35hz.
You have a lot of leeway in the crossover point since the Quads have usable output into the 50s. At the moment, they're crossed over around 150hz.
I have not heard the Quads I had a friend with a set but they were never set up, I hear Super Quads were quite the thing back in the day. I've heard several large Martin Logans and owned a small set of Magnepans for a brief time, I'm hoping the Quads are better.
IMO the numbers say the move is more sideways than progress, the touted benefit of the electrostat is it's relatively tiny mass compared to the air it is coupled to, the problem is that they are relatively weak and have minuscule displacement. I'm sure crossing over at 150Hz helps, does the displacement of the woofers modulate the Quads output noticeably?
Speaking of output, it appears the 2.83v sensitivity is just about 90.3 dB and 33v max input gets you another 21.3 dB, I can see why the stacked Super Quad was the way to go.
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