I really don't want to be dealing with multiple amplifiers if not absolutely necessary. While this wouldn't affect me personally, the system ideally needs to be as simple as possible so that my partner, family, friends etc can work it without needing to turn on a bunch of different electricals.
Let me make some points:
First, for some bass from such a small cabinet, you need a DSP.
Second, a passive subwoofer crossover is anything, but not simple, level matching near to impossible.
Last, you "simply" set the DSP inside the BRU5 with a laptop once, adjust the level and hide it. It is very small. End of story.
Rest assured, closed & DSP'ed is the most simple way to run a sub in your situation. If you want it complicated, expensive and with a non satifying sound, build a passive subwoofer system. About the worst you can do. Subs have been around for ages, but no one wanted them, because passive was complicated and sound was all but great in most cases. Then, surprise! The active sub made anyone wanting one.
Yes. Switching on things sucks. But, no switch, no coffee. The Devil made the switches on all these satanic things we use today.
First, for some bass from such a small cabinet, you need a DSP.
Second, a passive subwoofer crossover is anything, but not simple, level matching near to impossible.
Last, you "simply" set the DSP inside the BRU5 with a laptop once, adjust the level and hide it. It is very small. End of story.
Rest assured, closed & DSP'ed is the most simple way to run a sub in your situation. If you want it complicated, expensive and with a non satifying sound, build a passive subwoofer system. About the worst you can do. Subs have been around for ages, but no one wanted them, because passive was complicated and sound was all but great in most cases. Then, surprise! The active sub made anyone wanting one.
Yes. Switching on things sucks. But, no switch, no coffee. The Devil made the switches on all these satanic things we use today.
The main limitation here seems to be the placement and thus the maximum length in one dimension and it seems to be making a usable solution almost impossible.
There's a possibility of squeezing it between the fireplace and the TV cabinet instead, but this will a) be in plain view and b) in the line of fire from the dog. But it would be circa 200 × 250 × 500mm so a lot more roomy.
There's a possibility of squeezing it between the fireplace and the TV cabinet instead, but this will a) be in plain view and b) in the line of fire from the dog. But it would be circa 200 × 250 × 500mm so a lot more roomy.
That is 25 liters brutto. Quite a lot of volume. Find a nice 20cm woofer, build a closed box and you are done.
Such a sub is useless without an option to manipulate the frequency response, because you use it under the resonance frequency the driver has inside the box. Needs a lot of power, but usually is tighter than a vented cabinet.
Want help? A shopping list?
https://reckhorn.com/lautsprecher/lautsprecher-chassis/d-200-subwoofer-bass-chassis-20cm?c=120 Subwoofer
https://www.aliexpress.com/item/1005004895645420.html DSP-Amp
https://www.ebay.de/itm/386955352935 . Power Supply
Less than 150€
If you dislike the power supply (this one has a peak of 600 Watt and can be considered the optimum for the amp) there are many other options with all wires in place.
Such a sub is useless without an option to manipulate the frequency response, because you use it under the resonance frequency the driver has inside the box. Needs a lot of power, but usually is tighter than a vented cabinet.
Want help? A shopping list?
https://reckhorn.com/lautsprecher/lautsprecher-chassis/d-200-subwoofer-bass-chassis-20cm?c=120 Subwoofer
https://www.aliexpress.com/item/1005004895645420.html DSP-Amp
https://www.ebay.de/itm/386955352935 . Power Supply
Less than 150€
If you dislike the power supply (this one has a peak of 600 Watt and can be considered the optimum for the amp) there are many other options with all wires in place.
That seems to be an accurate observation. The other big issue is that the subwoofer's output level based on 4-inch drivers will be significantly limited. The choice of amplification will also make it difficult to set some reasonable blending between the subwoofer and the (small) mains. The on-board filtering is quite limited. There will be low-frequency and higher-frequency output from the system, but it may not be that smooth.
That space allows for a much larger subwoofer enclosure, which opens up many new and worthwhile possibilities. The dimensions you have provided produce an enclosure with a gross volume of 25 litres. If the walls of the enclosure are 18mm thick, then the internal volume will be about 16.3 litres. Allowing a further 14% reduction due to bracing, panel damping, and driver volume, we get an estimated internal volume of about 14.0 litres.
Agreed. A 20cm (8 inch) subwoofer is about the minimum size that can provide reasonable output and low-frequency extension, with some appropriate EQ.
Although it's not a DIY solution, considering that space is limited, a turnkey system such as the Edifier S351DB 2.1 bookshelf speakers with an 8-inch subwoofer might be worth considering (see photo below). They can take digital input from the TV and also have a remote control, which allows them to be switched on/off remotely. They can probably go reasonably loud as long as the listening distance or room size isn't too big, and the bass response also seems to be quite extended. By the time the individual costs of drivers, amplifiers, cabinets, etc are factored into the DIY solution, the S351DB seems like very good value for money, while still being quite compact.
The other non-DIY approach would be to use a set of KEQ Uni-Q Q3 Meta 2-way vented-box bookshelf loudspeakers. These are quite compact in size, with moderately extended bass response, and have excellent dispersion, and wouldn't look out of place either side of a TV. They need an amplifier of course, but there are plenty of those to choose from.
The previous model, the KEF Q350, may also be available at discounted prices.
A single Reckhorn D-200 woofer driver seems to work reasonably well in a PEQed closed-box enclosure of 14-litre net volume. The simulated results are shown below. A 2nd-order 160Hz Butterworth low-pass filter has been applied, and an f3=36.2Hz seems possible when PEQ of 4.5dB and Q=1.50 is applied at 42Hz. This produces about 98dB SPL with the driver almost reaching its Xmax.
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There is a price class which makes DIYS loose the competition with commercial offerings. If you just want a pair of good looking, small speaker with acceptable sound, a 200 Euro commercial offering will get you a sollution, if you buy smart. Just be sure you have a right of return, if your sound expectations are more than average.
Building a copy of that speaker DIYS will cost you more for wood, glue, paint, damping material, drivers, crossover components, wires, terminal an grill than 200€, not to mention your work and tools needed. You can not compete with a Chinese slave labour product, made without all the environmental regulations we like to have. All those speakers made at a low price point come from Asia.
What you don't get from China, is a high end speaker, custom made to fit in size and optics. If you are used to DIYS in your world, as many are, because they like it or can't effort the craftsman, you should own the tools and also some of the material anyway. You may have all the parts at home, except for drivers and electronics. You may even be happy with a raw cabinet, maybe painted with a quick spray bottle finish or wraped in wallpaper and painted matching the room.
So what you can not buy is individual style.
The parts I summed up give you something you will not get ready made with a 200€ budget. A high quality speaker with a cast aluminum basket, a high power amp with solid 220 Watt RMS and a DSP with a GUI that can adapt the low bass to the room. Not to mention the second amp channel, that may come in handy, later. There is no commercial product that can compete with DIYS here. Last, it can be made to fit a the narrow space that is available, usin cut to size wood from the hardware store, some screws and little glue.
Whether this fit's the individual situation and skills of the thread starter I don't know.
Building a copy of that speaker DIYS will cost you more for wood, glue, paint, damping material, drivers, crossover components, wires, terminal an grill than 200€, not to mention your work and tools needed. You can not compete with a Chinese slave labour product, made without all the environmental regulations we like to have. All those speakers made at a low price point come from Asia.
What you don't get from China, is a high end speaker, custom made to fit in size and optics. If you are used to DIYS in your world, as many are, because they like it or can't effort the craftsman, you should own the tools and also some of the material anyway. You may have all the parts at home, except for drivers and electronics. You may even be happy with a raw cabinet, maybe painted with a quick spray bottle finish or wraped in wallpaper and painted matching the room.
So what you can not buy is individual style.
The parts I summed up give you something you will not get ready made with a 200€ budget. A high quality speaker with a cast aluminum basket, a high power amp with solid 220 Watt RMS and a DSP with a GUI that can adapt the low bass to the room. Not to mention the second amp channel, that may come in handy, later. There is no commercial product that can compete with DIYS here. Last, it can be made to fit a the narrow space that is available, usin cut to size wood from the hardware store, some screws and little glue.
Whether this fit's the individual situation and skills of the thread starter I don't know.
... and the joy of listening to something you built on your own plus the learning experience!
Well, this is a large part of it. This would be my third speaker project, and the one with the most constraints in terms of size and placement.
I've done some more research, modelling a couple of options and come across a combination that looks interesting: pairing a SB17NRX2C35-4 with a SB20PFCR-00 in a ~14L box. Thoughts?
These are very nice drivers. If you buy them, be prepared to find a plasic basket on the passive radiator.
IMO this is no problem with a passive radiator, as the basket doesn't need to take up much energy. The passive cone is driven on its whole cone surface, not only on it's voice coil area. So the only parts that have to be rigid are the surround area and to some extend the spider's. I have a pair of these and the are really well made.
I don't think you would see any objective improvement from the plastic being cast aluminum. A smart place to use a cheaper material.
Fitted inside a cabinet the little bit of plastic that can be seen looks like cast aluminum.
IMO this is no problem with a passive radiator, as the basket doesn't need to take up much energy. The passive cone is driven on its whole cone surface, not only on it's voice coil area. So the only parts that have to be rigid are the surround area and to some extend the spider's. I have a pair of these and the are really well made.
I don't think you would see any objective improvement from the plastic being cast aluminum. A smart place to use a cheaper material.
Fitted inside a cabinet the little bit of plastic that can be seen looks like cast aluminum.
Just one point, the SB17NRX2C35-4 is no subwoofer driver.
The combination with the passive radiator would be used in a nice, compact 2-way speaker.
If you use a lot of trimming wheight on the passive, the poor SB17 will not have enough power to move it.
This is why there are dedicated subwoofer driver, which have a large coil travel, heavy cone, large voice coil and matching motor.
The combination with the passive radiator would be used in a nice, compact 2-way speaker.
If you use a lot of trimming wheight on the passive, the poor SB17 will not have enough power to move it.
This is why there are dedicated subwoofer driver, which have a large coil travel, heavy cone, large voice coil and matching motor.
Interestingly, two other drivers appear to be an option for extended bass (albeit at a large trade-off with SPL) using the same PR but with some weight added, in a much smaller box. At least, they do to my untrained eye.
Tang Band W5-1138SMF
Visaton W 130 X (DVC wired in parallel, resulting in 2ohm draw).
Tang Band W5-1138SMF
Visaton W 130 X (DVC wired in parallel, resulting in 2ohm draw).
@hodephinitely Thank you for providing the plots. If I may, I'd like to offer some small suggestions that help with the interpretation of the data. 1) use an upper frequency limit of 200Hz or 500Hz when plotting the low-frequency response; 2) use a lower frequency limit of 10Hz, or even 5Hz, to showcase the low-frequency roll-off behavior; and 3) use a dB range that covers at least 20dB of the SPL response function. All of these together make for plots that are a bit easier to interpret.
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The W130X has a very small surface area compared to the passive radiator and an excursion of +- 5.8mm with 10% distortion. A 6.5" passive radiator should be a better match.
Not anything you can do in a simulation makes sense in real life. You need to add some common sense, which comes from learning theory and doing practical work, as well as listening to people "that know". Maybe not anyones style. Some may be born as subwoofer designers, but those are quite rare I guess.
Not anything you can do in a simulation makes sense in real life. You need to add some common sense, which comes from learning theory and doing practical work, as well as listening to people "that know". Maybe not anyones style. Some may be born as subwoofer designers, but those are quite rare I guess.
That makes sense! I'd kept the high frequencies as I was messing with filtering and series inductors.
I was under the impression a good rule of thumb was to have at least 1.5 to 2x the Sd value for a passive radiator. What would be the negatives to having such a mismatch in this instance?
I do not understand why that should happen, unless the PR has a very nonlinear suspension, which again would be independent from weigth and a sign of very bad PR design.
Of course there can be a problem if you use a very big PR in a very small enclosure and for tuning low you have to add weigth up to the point where the suspension system is being deformed and gets non-linear.
It's similar to a single man pushing a huge ship. The ship will move slowly and take long, but it will move.
@Turbowatch2 Thank you for pointing out that the displacement figure of ±5.8mm corresponds to 10% THD. It's very good of Visaton to provide that sort of detail in their specifications.
From the magnet structure and voice coil winding height, it seems that Xmax = ±3.0mm for linear operations. That's quite a limited displacement capability. As long as a relatively low maximum linear output capability is acceptable, this driver does produce excellent low-frequency extension in compact enclosures.
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The PR displacement (Sd times excursion) should be double the active driver, regardless of size.
Since the PR diaphragm is heavy, it should be placed vertically, or it's displacement may only be around half it's rating, as it's weight will cause it to sag from the center position.
Since you want to limit your vertical height to ~100mm, that's the limit of your PR height.
There are oval "racetrack" shaped PR that have more Sd than a round PR.
The usual PR "Xmax" is generally just under or equal to Xlim or Xmech, the maximum the suspension can travel.
When the suspension reaches it's limits, a slapping ("pup-pup-pup") non-musical noise will be heard (and the suspension or cone may be damaged), while a driver passing Xmax just generates more harmonic distortion rather than nasty noises.
With little drivers with limited excursion, doesn't take but a few mm to go from 10% THD, hardly noticeable with most music, to over 100%, which is noticeable.