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This is the NHT SuperZero. Most of you are probably familiar with it -- inexpensive, super transparent mids and treble, lots of detail, and no bass. 1" silk dome tweeter, 4.5" paper cone/foam surround woofer. 86db 1w/m. Response down to 85hz.
NHT makes a matching subwoofer called the Super 8, which most reviewers like and say integrates well with the SuperZeroes.
However, I would like to take a different approach, and have a high-fidelity woofer system under each SuperZero that instead goes to 200 or 300hz to relieve the 4.5" woofer of all of it's bass and low-bass duties, allowing it to work in the range it is best suited for. Think smaller Wilson WATT/Puppy, or maybe like a separate bass helper like the full-range guys use. It would allow a true 3-way design and also provide the SuperZero with a stand.
Has anyone tried something like this before? Do you think it would give greater fidelity and stereo imaging that just using a single subwoofer? What size woofer would be ideally suited for this job?
Pretty simple. Whats the budget?
I like two 10" Seas L26ROY. It will play to low 30hz and is fine to 300hz.
I like two 10" Seas L26ROY. It will play to low 30hz and is fine to 300hz.
About 30 some years ago.
Works very well, much easier today with with active crossover, for example a MiniDSP 2x4 = $80 + $10 plug in + S/H
Plus amp(s) to drive woofer(s). This could be another receiver, integrated or power amp, something from ebay, flee market, garage sale, if amp section is quality as this is all that would be needed.
If the latter, must have analog input level control (simple potentiometer would do). Or DIY. We are here aren't we? 😉
Choose your woofer / enclosure type. The examples above should do quite nicely for your needs. 🙂
If this was an MLTL (very good bass properly done) one could possibly conceive a design where the Super Zero's used it as the stand or completely integrated into. Seperate allows a bit more placement optimization, but is limited by the upper crossover frequency of the bass section. If a true sub crossed below 100 or better ≤80Hz. If higher say in the 200-300 range this becomes an issue with driver spacing for proper integration, Hence all in one eg a single 3 way speaker.
Cheers,
Mike
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wow, those Seas drivers look extremely well-built! They're also not much more money than Peerless or Vifa... nice
I may go with a slightly smaller size woofer for faster transients though, as it doesn't have to be efficient to match the 86db of the SuperZero
Good post, thanks.
I'm glad things like MiniDSP exist today to help with projects like this.
Do you think it would be wiser to keep the added woofers in the <80hz range? I do want to relieve the 4.5s of as much excursion as possible to keep distortion down and headroom up. Maybe a crossover point somewhere in the 150hz range would be a good compromise? After all, having 4 separate enclosures would allow me to align things physically for integration.
Well this is a preference call the end user YOU would need to find out. Different rooms react, well differently. What type of setup are we looking at music and or HT? Size of room and the intended placement are crucial. Furnishings?
This is for a 2-channel music system that is going in a small room of 10'x12', of which an entire 12' wall is dedicated to the hifi. The room is fully furnished and is carpeted, and I'm not beyond putting up acoustic foam if I have to.
A Peerless SLS 830668 looks like an interesting option. The Madisound Speaker Store
Is the SLS series up to the task of providing accurate bass that would match the SuperZero? Or perhaps should I be looking at a higher-end woofer? Perhaps two smaller woofers?
I did this with some success a few years ago. Second order highpass filter, Q=0.6, at 90Hz to the NHTs (resulting in a fourth order acoustic L-R), fourth order L-R low pass to the woofers. Used an analog electronic crossover (these days, I'd use a digital unit like the DCX2496). The woofers were a pair of Dynaudio 17W75s per channel in 1 cu ft sealed boxes. The bass wasn't deep, but it was tight and well-defined. My impression was greater clarity from the Super Zeros along with the expected greater solidity. Nothing special about the Dynaudios other than that I had them on hand.
"Transient response" is just not an issue with a woofer having a crossover this low.
The other issue to attack is the hole in the midrange (you can hear it very clearly with pink noise), which requires a bit of passive crossover rework.
"Transient response" is just not an issue with a woofer having a crossover this low.
The other issue to attack is the hole in the midrange (you can hear it very clearly with pink noise), which requires a bit of passive crossover rework.
IMO in this case absolutely not. A large diameter driver will handle the <300 hz range far better than the small one. If you are going to do this as a 3 way then do it properly, the way that you described in the first post. Lobing from driver spacing and higher crossover will not be an issue in this case especially with a dsp and a steeper filter.
If you are set on a smaller woofer look at the Dayton RSS210HF 8" sub woofer. It is a true sub, goes deep in a small box and can play clean up to 600hz.
The peerless might not play well up high. The Seas recommended earlier is a great option if you don't mind the larger box or the Dayton if you want it a bit smaller. You can even stack a pair of the daytons for higher SPL though in such a small room I doubt you'll need it. Both are really well built drivers and sound great.
Highly recommend bass traps and treatment for this room size and dimensions. You'll be pleasantly shocked by the difference.
It's been used up to 400 hz as the bottom of a well regarded 3-way
https://sites.google.com/site/undefinition/tarkus
One concern I have is how much louder this can be. In such a small room the tendency for the young is to push it to the limits on occasion. Doing this allows you opportunity to do an impressive amount of damage to your ears in short order. When the lower bass is removed with lets say a crossover point of 350 the SuperZero's power would be halved, this alone give you 3dB more capability. Also due to the extreme excursion of deep bass being removed from the picture, mainly the physical limit eg Xmax allows far more spl capability in addition to the power response being increased. Gets real easy to burn voice coils doing this.
Protect your ears is all I'm say'n, you only get one pair 🙂
Advantage of doing this other than extending much lower with real acoustic output is the removal of the low frequency excursion demanded of the SZ's midbass greatly reduces FM (doppler) modulation out of the midrange, cleaning it up, so to speak clarifying what once was muddy water. It also improves dynamic headroom, transients will become more distinct.
2 ten inch woofers are ALOT for a room this size and not the best setup. Better would be 4 smaller subs distributed (per Geddes) crossed at ~100 to be reasonable with how it could be setup. This would help minimize the prominent standing waves in this rather cuboid room. In this scheme two of four could be made as the stand or integrated as a 3 way, with an additional two that help fill in the gaps. Crossed this low one should not be able to pick out their location.
Grab REW it's free and run the Simple Room Simulator to get an idea of best placement, Keep in mind time alignment and listening position / height
Protect your ears is all I'm say'n, you only get one pair 🙂
Advantage of doing this other than extending much lower with real acoustic output is the removal of the low frequency excursion demanded of the SZ's midbass greatly reduces FM (doppler) modulation out of the midrange, cleaning it up, so to speak clarifying what once was muddy water. It also improves dynamic headroom, transients will become more distinct.
2 ten inch woofers are ALOT for a room this size and not the best setup. Better would be 4 smaller subs distributed (per Geddes) crossed at ~100 to be reasonable with how it could be setup. This would help minimize the prominent standing waves in this rather cuboid room. In this scheme two of four could be made as the stand or integrated as a 3 way, with an additional two that help fill in the gaps. Crossed this low one should not be able to pick out their location.
Grab REW it's free and run the Simple Room Simulator to get an idea of best placement, Keep in mind time alignment and listening position / height
Transients are not just an issue of less weight. It has to do with motor strength vs. cone mass. That 10" will not be outdone in transients by a smaller cone.
When you push a small cone to have bass extension, it also has huge distortion. Bigger cones more far less distance to move the same amount of air. When a cone moves a lot to make up for limited displacement, the voice coil moves out of the mag field. A TC sounds 18 will move faster than the 10". That 18 has an 81lb mag and the resulting motor force is able to move the cone faster than a 8" with a weaker motor. Its like a 130 HP Honda civic in a race againgst a 1400hp Hummer. The Hummer is faster because of its power to weight ratio.
The transients of that 10" are shocking. Its cone is only 106grms.
Mr. Linkwitz. Start with his comments on group delay.
He's a big fan of dipoles but his various writings on cross over integration are worth reading before you buy anything. He's pretty heavy on the math (Eg. crossovers) but it's worth understanding the impacts (even if deriving the math is beyond one).
Mr. Olson. (Good bass)The extremely long winded Beyond the Ariel thread (9000 posts and counting) has also tossed up the opinion that high Qms is beneficial (along with basics like usable T/S parameters and well behaved cone break up modes.
Go and read Linkwitz. The 'language' we use is all screwed up; but in a nutshell evolution has wired us to be very sensitive to first arrival time and the min/max pressure points of twig-snaps and other pressure-related events.
It is very easy to mess this up in subwoofer crossover designs which results in unrealistic results. "Time alignment" and "linear phase" are a much better place to start a discussion on these topics.
But instead we have "flabby" and "fast" and "attack" and "transients" and "tight" and other I-can't-be-bothered-reading-the-existing-literature descriptions of this part of our hearing.
I'm pretty familiar with Linkwitz's work- he was even kind enough to cite some of my writings.
The issue here is polar pattern and sensitivity to offset of the acoustic center. The LR4 is particularly insensitive to those variables, and having a sharper cutoff of lows from the small driver allows an increase in dynamic range. This indeed was the case with the NHT/Dynaudio combination that I used for a few years, so much so that this was incorporated into my NHT M3.3 project.
The offset is easier to deal with these days in the digital domain.
Some rebuilt Acoustat 1+1, then highly modified biamped NHT M3.3. Yes, I like them better, but the Super Zero system was excellent in its own right. The NHTs replaced some MTM speakers I had built with Audax HM170Z0 (my ex-wife's cats destroyed the Audaxes, and the drivers were discontinued by then) and were not a large step down, to be sure!
Like I mentioned, run some pink noise into the Super Zeros. Note how easy it is to hear the woofer and tweeter separately.
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