Project – 2 x Peerless XLS 10” 20Hz tuned slot port subwoofer

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I've modelled my build in Hornresp, and I was surprised to see a hump in response at tuning frequency 20Hz. Granted it's only slightly different to that modelled in Winsid, I'm just concerned I've made a mistake in the modelling in Hornresp. This is with 350W on each driver, no filtering. Excuse the "QWTL" in hornresp title/decryption, this is a mistake, I copied from a previous plan for a 1/4 wave transmission line.

Are there any Hornresp experts out there that could kindly verify my design ?

I'm ready to order my MDF for the build, just need to double check my design and cut sheet.


Cheers
 

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HR doesn't account for any natural losses due to friction/whatever, hence the peaking at Fb, sharp vent pipe resonant spikes in the mid-bass, etc.. Use the Wizard to add a bit of damping and it rolls off nice. ;)

Have you checked the vent mach? Lossy inductance?

GM
 
HR doesn't account for any natural losses due to friction/whatever, hence the peaking at Fb, sharp vent pipe resonant spikes in the mid-bass, etc.. Use the Wizard to add a bit of damping and it rolls off nice. ;)

Have you checked the vent mach? Lossy inductance?

GM


Thanks GM, appreciate the explanation. I've modelled with a Lossy LE, and results are attached, appears to have smoothed out the response. Interesting now comparing the Hornresp model to the Winisd, seems like there's a 2dB increase on the HR model over the Winisd, with a corresponding increase in excursion. I had to double check my power inputs, but they appear to be the same.

As for velocity, I'm not sure where HR shows this. WInisd modelled port velocity at 21.5m/s @19.5Hz (≈6% SoS @ 343m/s)

Thanks
 

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25mm MDF cut to size and delivered, getting the Jigsaw and Router out saturday for the finer detailed cuts.

I anticipate having the enclosure built in two weeks, and will assemble for a trial pre coating.

I'm in a position to order the Crown XLS amp, unfortunately the 1002 price has gone up from £239 to £279. The 1502 at £324 (extra £45) now looks like more value for money. It has a better S/N ratio, and bridged 8 Ohm is 1050W, compared to the 1002 700W. Bearing in mind, my drivers combined are technically rated at 300W, but I'm tempted as you can never have too much power, I can limit the power, and its future proofed should I build a bigger design in the future. What do you reckon?
 
Behringer inuke,? You also have a version with buit in dsp

Considered that option at length. I require a HPF in the mid teens, and the Inuke only allows you filter down to 20Hz, and also the fan is very loud - not good for a living room. You can do a subsonic fudge on the inuke by applying a HPF at 20Hz, then boosting with a low shelf (?), but effectively lose 75% of available power output. Also, the fan can be changed out but I'm not willing to invalidate the warranty on a new item.

So either the XLS 1002 at £279 or the XLS 1502 at £324. I'm also getting a minidsp 2x4 at the same time. The only item being budgeted for later is the calibrated Umik microphone.

This sub is going ahead. Hope to get some pictures up of the build in next week, I anticipate completion in 2 weeks
 
If I hadn't moved into an apartment I would have made something like this with the XLS 10"s I have.

Though I don't know if the bracing is restricting the internal air to much

External size 40x40x120cm. Internal volume 105 liters with a port tuned(12x12x103cm) to 20hz.
 

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the t.racks DSP 4x4 Mini – Musikhaus Thomann

Did you ever consider this DSP? Much better if you want to use a PA amp, as it is symmetric. Easy to use a symmetric DSP with asymmetric, but not the other way round!
Also cheaper and better build than the plastic miniDSP.

Maybe you have a look at Thomann´s amps too, as Crown is average OK, but not the holy grale of amps.

You can still buy tax free in Europe, will be over soon...


PS your Crown juwel XLS1002 is 279 € wait, I´l do it for you: 247 GBP incl. P&P from Thomann.
yes, that was the EU, you could buy where you wanted...
 
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@CCU
Do the bracing in a different way, use simple 5cm x (40cm - two times the panel strength) and place them at the sides where they are needed. For your cabinet I would estimate 3-4 per side. By not putting them on the same height, you will have enough way for the pressure and prevent the panel from flapping in and out. Try to do it asymmetrical, as this will break up unwanted resonances too. I personally prevent to have any un braced area of more than 12cmx12cm, this depends a bit on the panel you use. The test is knocking with your finger at the outside of the cabinet. If it is dry, sharp "tack", you are OK, if you feel a more soft "tock", the panel vibrates. This stability is important with closed and vented cabinets and you find it in any simulation as a loss factor. Really working bracing is easy, but for some reason hated by DIYS, even more by the industry. B&W went away from the perfect matrix they once did, but only for cost reasons, as even the people in Malaysia started to demand money for their work hours (How could they?).
You can do it at hardly no cost as a hobbyist.

Your curved channel looks nice, but the air is more picky at the start and end of the port than in a bend. It likes trumpet like openings to find it´s way in and out.
Your plan makes it too complicated. Better try to use two sides of the cabinet and don´t build a completely separate construction as port.
 
If I hadn't moved into an apartment I would have made something like this with the XLS 10"s I have.

Though I don't know if the bracing is restricting the internal air to much

External size 40x40x120cm. Internal volume 105 liters with a port tuned(12x12x103cm) to 20hz.

If you're concerned about restrictions, use a hole saw to turn the bracing into swiss cheese, reduce the mass but retain most of the strength.
 
the t.racks DSP 4x4 Mini – Musikhaus Thomann

Did you ever consider this DSP? Much better if you want to use a PA amp, as it is symmetric. Easy to use a symmetric DSP with asymmetric, but not the other way round!
Also cheaper and better build than the plastic miniDSP.

Maybe you have a look at Thomann´s amps too, as Crown is average OK, but not the holy grale of amps.

You can still buy tax free in Europe, will be over soon...


PS your Crown juwel XLS1002 is 279 € wait, I´l do it for you: 247 GBP incl. P&P from Thomann.
yes, that was the EU, you could buy where you wanted...

Never claimed the crown XLS was the holy grail / crown jewel of power amps. Even looking on Thomann, my budget allows for only T.amp or Behringer. I haven't picked the XLS with emotion, it was chosen for 3 reasons - power for money, ability to select low input sensitivity and inaudible fan due to it being in my living room. There's a market for Crown XLS amps, same as there is a market for diesel VW cars for example - everyone has their own criteria when making a purchase of a product.

The T.amp DSP is very interesting, will have to research it. If it doesnt allow setting of filters below 20Hz, I can't use it.
 
If you are on a budget, consider the Behringer KM750. For normal use, you can disconnect the fan, for demanding use put a temperature regulated inside. No problem, no warranty labels, if it breaks, just retrofit. Thomann gives you 3 years security. Really fine amp, I stumbled over one, was positively surprised and used it for a while.
Don´t look for used Behringer, they trade hardly for as new if you consider P&P.
You can not loose money you have not spent, if you trade your amp later. A factor many forget when talking about resale value... Anyway, if you want to sell it, don´t take any heavy amp, it is Class-D and SMPS age.

The sub 20 Hz can be done with the T-DSP, but you have to combine filters.
Honestly, I believe you really have no idea what you have to expect "sub 20Hz" and what you have to adjust there, exactly from 10-20. I think you are making your self some illusions. Have you ever had the idea many DSP´s don´t go that far, just because it does not matter? A few other inputs in the software do not cost anything...
 
The sub 20 Hz can be done with the T-DSP, but you have to combine filters.
Honestly, I believe you really have no idea what you have to expect "sub 20Hz" and what you have to adjust there, exactly from 10-20. I think you are making your self some illusions. Have you ever had the idea many DSP´s don´t go that far, just because it does not matter? A few other inputs in the software do not cost anything...

I need a subsonic high pass filter to protect the drivers!

And I'm not surprised you dont understand that, given that you're recommending removing the fan from electronic equipment, which leads to inability to dissipate excessive heat. I've seen enough electronic equipment fires to know how careless your recommendations are.

Take your suggestions elsewhere!
 
Mock-up of the build - just the panels arranged. I've started assembling, struggling if I'm honest, but will just take longer than expected. Bought an XLS 1502, so just need the sub built now. XLS 1502 should cover my future intentions, as this build is a trial for something bigger and better in the future.
 

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Literally just put the last panel on tonight and started with a bit of filling. Will fill, sand and trim edges that didn't line up perfectly. Hoping for good weather at the weekend so I can take it outside, to jigsaw some feet out of the bottom of the side panels and roundover all the edges.

Happy with the build, first one in nearly 20 years and by far my most complicated.
 

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Hi All,

FYI:

b:)
 

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Many thanks Bjorno, appreciated. A lot of info, I'm looking forward to digesting it when I get a chance. Initial observations - looks like I should have used damping, although I currently have a 24db per octave low pass set around 50Hz, so hoping this meets your stated less than 65Hz? And I luckily got the port size correct!

Finally got the box finished today, had a trial this afternoon and was a bit blown away. I dont have a basis for comparison, and maybe my expectations were too low, but playing some electronic music with low frequency content had my sofa and house rumbling. It looks a bit over the top, but I guess that was the point. Painting next ....
 

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