It's ok, I appreciate sub eye candy. Good job with those. The efficiency of the Tapped horns does make them interesting, but they are still a bit larger than I want in my living room right now. My goal is to be able to produce in excess of 115 db's from 20hz to 200hz, and then around 105db's from there. As you well know, the Abbey can easily do that, but subs that can do an honest 115db's with sufficiently low distortion, compression, etc, are rare.
My two current main subs are capable, together, of around 120db's max in that lower range, but aren't so great above 50hz, so I'm hoping the Bandpass will improve that area. While I know that I will rarely ever exercise this system to that level, I also know that having the range allows it to do so without sounding hard or stressed. I feel like a big action movie (which I love) is just lost when the sound is small.
Oh Patrick, didn't you mention using tube amps with your Summa's sometimes. I have a nice 805 SET amp capable of around 40 watts rms per channel. Thats pretty big power for a single ended triode. It was sitting in the basement of my parents house because I didn't have room for it when I first moved out here for Grad school, and they were willing to store it. I finally grabbed it last time I was home. I haven't really used it much, it heats the room up too much, but it was fun listening to some classic rock, jazz, and blues albums through this class 1940's designed amp.
My two current main subs are capable, together, of around 120db's max in that lower range, but aren't so great above 50hz, so I'm hoping the Bandpass will improve that area. While I know that I will rarely ever exercise this system to that level, I also know that having the range allows it to do so without sounding hard or stressed. I feel like a big action movie (which I love) is just lost when the sound is small.
Oh Patrick, didn't you mention using tube amps with your Summa's sometimes. I have a nice 805 SET amp capable of around 40 watts rms per channel. Thats pretty big power for a single ended triode. It was sitting in the basement of my parents house because I didn't have room for it when I first moved out here for Grad school, and they were willing to store it. I finally grabbed it last time I was home. I haven't really used it much, it heats the room up too much, but it was fun listening to some classic rock, jazz, and blues albums through this class 1940's designed amp.
JEEZ Matt! So impatient. I am looking at them now, just took them a few hours ago and need to touch them up.
I *did* try a tube amp. Honestly, I've NEVER heard a difference between amplifiers until I bought the Summas. Was always a bit mystified to see the money that people invest in amplifiers at audio shows. If anything, I thought tube amps made speakers sound WORSE. For instance, I've heard a lot of tube amps with speakers that have a harsh top end, and the tube amp seems to be doing little more than adding a nice euphonic haze and rolling off the top end.
But the Summas changed my opinion on that completely - there was clearly an improved sense of "space" with the tube amp, and a noise floor that was so black, instruments appeared out of thin air.
Absolutely magical.
haha, I'll just tell them it was a gamma ray burst. Those can shake a house right?
Like I said, I know I will not listen at those levels, I know I will rarely ever even come close to those levels, but action flicks with big low frequency effects sound small at too low a level, and distorted and muddy at those more realistic levels.
I'm watching a tv show on the History channel right now, and I'm sure I'm not even at 75db's, this is how the system is more often than not. Even with Music, I don't typically listen at really loud levels. The issue comes when i do choose to listen at loud levels, I really am bothered when it sounds compressed. Maybe it's my ears that are compressed.
Like I said, I know I will not listen at those levels, I know I will rarely ever even come close to those levels, but action flicks with big low frequency effects sound small at too low a level, and distorted and muddy at those more realistic levels.
I'm watching a tv show on the History channel right now, and I'm sure I'm not even at 75db's, this is how the system is more often than not. Even with Music, I don't typically listen at really loud levels. The issue comes when i do choose to listen at loud levels, I really am bothered when it sounds compressed. Maybe it's my ears that are compressed.
I've actually not heard many tube amps with very good noise floors. The best I did hear was the Bella Xtreme's from Response audio, but far too expensive. When I bought my turntable from him, he let me listen to his Bella amps, and he really did a good job with those designs. He helped me do some modifications to the design of my own amp and get it's performance passable. I think I mentioned on another forum I got this as a damaged item shipped from China for this modification company I worked with for a summer, and he was recommended to help me actually modify the design.
I actually replaced a lot of parts with audiphile type parts, I know it's blasphomy, but most of them made no real difference. Circuit changes made a big difference, certain coupling caps made a small difference, but other than that, nothing big.
What I like about these SET amps is that they don't have the switching distortions common in most amps today, and so for lower level material, I find it sounds cleaner. What I don't like is their reliability, fickleness, heat production, and commonly their less than stellar s/n ratio.
Two more reasons, that some tube amps sound so good, are simple circuits and very low amounts of negative feedback. On the other hand, using large amounts of negative feedback will make an amp measure better, but usually does not sound as good.
Tom
There is a little understood characteristic about feedback, and that is that it tends to spread nonlinearities to ever higher orders. If higher orders are more audible (and they are) then this could make things sound worse, instead of better, while making the numbers look better at the same time. A clear cut example of the pointlessness of standard measures of nonlinear distortion.
Matt, Matt, Matt, just a few days more, maybe even one! Than all your wishes will be answered.
I saw the subs in process today at Earl's place. Pretty darn cool, but elegantly simple in execution for sure.Matt, Matt, Matt, just a few days more, maybe even one! Than all your wishes will be answered.
Sorry, no pics here either
Tom
I saw the subs in process today at Earl's place. Pretty darn cool, but elegantly simple in execution for sure.
Sorry, no pics here either
Tom
Later today.
I'll post the data shortly. They are about 14" x 16" x 18". Bandwidth about what Matt says, but the efficiency is considerably higher that what Matt says I believe, but I need to check on that (for free-space this might be correct).
Oh sorry if I misrepresented it, I think that is what you had previously posted. It was probably a number based on free space.
When you do post data and picks, I'd love a little discussion about enclosure construction. For instance, materials used, is there CLD, cabinet thickness, bracing, foam in the ports, what sort of perturbation does the multiple ports with multiple tunings have on the bandwidth (I'm not sure if that is a word that makes sense here, but I assume that multiple ports will have the effect to change the bandwidth and response shape some).
I'm curious to know about the compression behavior of these at high levels too. You mentioned in the past that bandpass subs have the advantage of offering a reduction in distortion due to the acoustic filter of the bandpass system. Does this mean that the sub will sound less "overdriven" as it begins to reach it's limits?
When you do post data and picks, I'd love a little discussion about enclosure construction. For instance, materials used, is there CLD, cabinet thickness, bracing, foam in the ports, what sort of perturbation does the multiple ports with multiple tunings have on the bandwidth (I'm not sure if that is a word that makes sense here, but I assume that multiple ports will have the effect to change the bandwidth and response shape some).
I'm curious to know about the compression behavior of these at high levels too. You mentioned in the past that bandpass subs have the advantage of offering a reduction in distortion due to the acoustic filter of the bandpass system. Does this mean that the sub will sound less "overdriven" as it begins to reach it's limits?
Intentional and important. If they are all symmetrical then the ports pick up the same standing wave in the front cavity. This way they all hit different spots and different modes. The four ports here can be longer than a single one in the center because that where the woofer magnet is. Longer ports allow for less sound leakage above the box tuning, which can be a big deal in these designs.
Also, four ports like this can do what one cannot and that is static flow of hot air. There will be a cross flow of air as this box heats up that will have no effect on the sound, but will help to cool the magnet. One port can't do that. They are small for damping, thus elliminating the need for foam to dampen the resonances.
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