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

[mart34]

Hi all,

I have two Peerless 830452 drivers which I’m planning to put into a single slot ported enclosure. Picture of both drivers attached. I know I should be building two separate units to smooth out room modes but my partner would not accept this.

I know these drivers are best suited for either sealed enclosures or enclosures with passive radiators, but I’m going ported. One of the reasons passive radiators are desired to compliment this driver, is due to sealed configuration not achieving good LFE due to steep roll off, and the ported configuration requiring very long and large csa ports to achieve good LFE without excessive port noise. Size is not an issue for me, I am only limiting myself by attempting to use a single 1220x2440 (4ft x 8ft) MDF panel. So, I’m going with a 3.38 cubic foot enclosure, tuned to 20.6Hz with a slot port 11 x 3 x 55” long (27.5cm x 7.5cm x 140cm long), which limits port velocity to 21.5m/s @19.5Hz (≈6% SoS @ 343m/s) with 350W on each driver. This slot port has a csa equivalent to a single 6.5” diameter round port, which sounds very reasonable for two 10” drivers. Note: Peerless quote the XLS driver at 150Wrms, however, it’s well known these drivers can handle more, with majority of users running these at double their quoted rated power handling. 350W per driver pushes excursion to 13mm at ≈28Hz, peerless quote the xmax @12.5mm and I’ve seen reports the Xmech is around 20mm so no issues. Cabinet will be 1” MDF all round, with double thickness front baffle. I’ll round over the edges, and will attempt to paint for best finish I can possibly do (fair at best).

My current system consists of a digital source into a Denon AVR-1907 AV amp, currently powering two floor standing speakers in stereo.

Due to budget limitations, I have two options –

1. Buy a minidsp 2x4 HD and configure two AO in stereo for the existing floor standers, and two AO in mono for the subwoofer drivers, and feed all four as analogues into the AV amp (Front L, Front R, Surround L, Surround R) providing 120W per channel. Note: The Denon av amp has 7 analogue ins, which can be used where the audio is decoded outboard in a DVD player for example and 7 analogues come into the amp from the player. Using the amp and minidsp in this manner, I’ll have a better low pass filter, and will be able to configure a sub-sonic HPF. Although specification states 6-8 Ohm loads, I’ve found Denon techs online stating that 4 Ohm loads can be driven with their AV amps – worst case I trip on over-current protection at higher volume levels.

2. Buy a crown XLS 1002 drivecore series 2 and run with the built in LPF, but I’ll have no sub-sonic HPF. This would be connected to the AV amps sub-out. In this scenario, I’ll have to set limiters on the amp, which will be configured to not breach 20mm Xmech, which equates to 220W total (110W per driver). This is less power than if I were powering direct off the AV amp, so I don’t really gain from this option !


If I buy the amp, I’ll buy the minidsp next year, and visa versa, so next year I’ll have both. My preference is to go the minidsp route, since power will be approx. the same and I get to play with a very cool box of tricks !

Winisd modelling attached for 350W per channel. Note: No HP or LP filters configured in the modelling, I have however put a second order high pass butterworth @ 8Hz to simulate the XLS natural roll off.

I’ll model it in Hornresp too when I get a chance.

Couple of questions:-
· Can someone kindly verify my design ?
· Any foreseeable issues ? anything I’ve overlooked ?
· Opinions on which option to go for, crown XLS or minidsp ?
· Anyone see a problem with me using the AV amp the way I’m planning ?


Any advice and answers would be appreciated !! Many thanks in advance, Martin

Peerless 830452 data sheet here – https://www.parts-express.com/pedocs/specs/264-1108--tymphany-xls-p830452-spec-sheet.pdf

Denon AVR-1907 manual here - http://www.google.co.uk/url?sa=t&rc...r-Manual.pdf&usg=AOvVaw39Kj6qKK6h3Jud7lutRdvk

Minidsp 2x4 HD manual here - https://www.minidsp.com/images/documents/miniDSP 2x4 HD User Manual.pdf

Crown XLS 2 drivecore manual here –
https://www.google.co.uk/url?sa=t&r...original.pdf&usg=AOvVaw0HgdqqGoTxTJKGz8SB-xZs

 

[rabbitz]

I'd build a more cube box with the drivers opposing (on opposite faces) so you get push-push and place the slot at the back or bottom. I use the 830452 in a side firing vented design with a down firing port.

 

[mart34]

I'd build a more cube box with the drivers opposing (on opposite faces) so you get push-push and place the slot at the back or bottom. I use the 830452 in a side firing vented design with a down firing port.

Thanks but I'm putting both drivers on the front. I've gone over many different options for the construction, and I require a slim enclosure, but can accept tall and deep. If I put a driver on front and one on the back, I have no idea where the 1.4m port is going.

Plus i just have a personal preference for both drivers to be on the front .... it will weigh quite a lot so I wont be losing too much of the gains from opposed drivers.

 

[mart34]

I'd build a more cube box with the drivers opposing (on opposite faces) so you get push-push and place the slot at the back or bottom. I use the 830452 in a side firing vented design with a down firing port.

Should have asked - are you happy with the performance of the 830452 in your vented enclosure ?

Cheers

 

[rabbitz]

My port is on the bottom.

I've been using the 830452 sub since 2004 and never had an issue but I only use it for movies where it works a treat. No chuffing or bottoming out with my domestic use (250W plate amp). Some builders have had problems with the larger 830500.

 

[mart34]

My port is on the bottom.

I've been using the 830452 sub since 2004 and never had an issue but I only use it for movies where it works a treat. No chuffing or bottoming out with my domestic use (250W plate amp). Some builders have had problems with the larger 830500.

Nice build, liking the huge flared port. What's the tuning frequency?

 

[Jag768]

Nice build. I have 8 xls10s in use at home in 4 sealed enclosures in a multisub setup. I would go ported if I ad the space.

Just one remark at the moment: I would buy the regular minidsp rather than the hd version; it's cheaper and actually better since the hd version has some issues with accuracy of the filters in the sublow frequency range

 

[mart34]

Nice build. I have 8 xls10s in use at home in 4 sealed enclosures in a multisub setup. I would go ported if I ad the space.

Just one remark at the moment: I would buy the regular minidsp rather than the hd version; it's cheaper and actually better since the hd version has some issues with accuracy of the filters in the sublow frequency range

Thanks. 8 XLS 10" sounds rather impressive, do you have any photos / threads on your build? would be great to see that.

Regarding the Minidsp 2x4 HD, that's the first I've heard about filtration issues - do you have any further specifics about the issue so I can research online? Reason I'd considered the HD is due to the Digital Input which I need since my source is digital, and the fact it has a higher output voltage - 2V I believe. The standard minidsp only has max 0.9V. The crown XLS has two input sensitivities - 0.775 and 1.4V, but I'm still concerned I wont have the Vout to maximise the crown gain.

 

[mart34]

In fact, my budget this year might allow a third option -

3. Buy a crown XLS 1002 and a minidsp 2x4 (cheaper non HD version).

But for this option I'm really concerned the minidsp Vout wont be compatible with the Crown XLS input sensitivity. Has anybody used these two together? 0.9V out of minidsp into Crowns input with a 0.775V input sensitivity?

This sounds ok to me, but after hours of searching over last few months I haven't been able to confirm this anywhere.

Thanks

 

[rabbitz]

What's the tuning frequency?

Fb=27.5Hz

There's an application note for the 10" XLS driver.
http://www.tymphany.com/wordpress/wp-content/uploads/2018/10/Appnote-xlssub.pdf

 

[audfrknaveen]

Thanks for sharing !!! This application note is useful

 

[mart34]

Thanks, I've read the application note before, very informative. I've treated my design like a numbers game, and have designed for flat response down to 20Hz. How this performs "in room" with room gain, will be interesting to see once I'm able to afford a calibrated mic. My main goal was for flat response over the audible range (down to 20Hz), primarily for electronic music, and secondary to that - also for movies.

 

[audfrknaveen]

Good to know !!!
What do you use to boost the low frequencies ???
Something like mini DSP ??

 

[mart34]

Good to know !!!
What do you use to boost the low frequencies ???
Something like mini DSP ??

I'm not planning on boosting anything, the design is such that the response is flat in the audible range. Ported designs cant compete with sealed for subsonic extension, and I cant boost in the subsonic range due to mechanical limitations of the ported designs. Plan is to use a minidsp parametric equalizer to tune out room modes, but this would typically involve attenuating the peaks in frequency response caused by the room, to eliminate the boominess which is an unavoidable consequence of achieving flat response to the lower end of the audible spectrum. This will be once I get a microphone and use with REW.

 

[Jag768]

Thanks. 8 XLS 10" sounds rather impressive, do you have any photos / threads on your build? would be great to see that.

Regarding the Minidsp 2x4 HD, that's the first I've heard about filtration issues - do you have any further specifics about the issue so I can research online? Reason I'd considered the HD is due to the Digital Input which I need since my source is digital, and the fact it has a higher output voltage - 2V I believe. The standard minidsp only has max 0.9V. The crown XLS has two input sensitivities - 0.775 and 1.4V, but I'm still concerned I wont have the Vout to maximise the crown gain.

Here is the build thread. I started doing a cardiod sub experiment, ended up using 4 monopoles (sealed dual xls10), optimized using MSO.

About choosing hd or non-hd, here's more info
AVSforum thread on the subject
MSO creator's take
Measurements showing unwanted LF filter behaviour

 

[Entas]

So non-HD version is better to use if i want to filter low frequencies at this point subwoofer?

 

[mart34]

Here is the build thread. I started doing a cardiod sub experiment, ended up using 4 monopoles (sealed dual xls10), optimized using MSO.

About choosing hd or non-hd, here's more info
AVSforum thread on the subject
MSO creator's take
Measurements showing unwanted LF filter behaviour

Wow, that's a ridiculously impressive build, would be great if you could put a video on YouTube!

Thanks for all the detailed links on minidsp. That was all totally new to me, I'm surprised this doesnt get mentioned more on forums and reviews of the HD version. Clearly there is a high risk I wont be able to accurately set a subsonic high pass filter, which is too risky due to the potential mechanical damage of my drivers. So, minidsp 2x4 (non HD) it is for me. One of your links even mentioned that the output voltage just has to be higher than the fed amplifiers maximum voltage in, so the minidsp 2x4 output voltage of 0.9V is good for the Crown XLS series 2 maximum input voltage of 0.775V.

Thanks very much

 

[mart34]

So non-HD version is better to use if i want to filter low frequencies at this point subwoofer?

My interpretation is that although you have the ability to set filters / EQ down to 10Hz, the closer you get to 10Hz the more inaccurate the filters/EQ will be, and not by just a minor amount but it could potentially be substantially inaccurate.

 

[Jag768]

Wow, that's a ridiculously impressive build, would be great if you could put a video on YouTube!

Thanks for all the detailed links on minidsp. That was all totally new to me, I'm surprised this doesnt get mentioned more on forums and reviews of the HD version. Clearly there is a high risk I wont be able to accurately set a subsonic high pass filter, which is too risky due to the potential mechanical damage of my drivers. So, minidsp 2x4 (non HD) it is for me. One of your links even mentioned that the output voltage just has to be higher than the fed amplifiers maximum voltage in, so the minidsp 2x4 output voltage of 0.9V is good for the Crown XLS series 2 maximum input voltage of 0.775V.

Thanks very much

Im not really into making youtube movices but thank you . Actually building 4 sealed subs was no rocket science, just a lot of work . Getting all 4 subs to produce flat response at multiple listening positions was the hardest part. But if you spend a lot of time in MSO, you always get it right .

My interpretation is that although you have the ability to set filters / EQ down to 10Hz, the closer you get to 10Hz the more inaccurate the filters/EQ will be, and not by just a minor amount but it could potentially be substantially inaccurate.

Thats right. And the problem is that the filters start "peaking". However, i can't find any measurements on the HD version of the miniDSP, which is different from the 4x10 version. So i don't know if this issue relates to the miniDSP HD version. But if input sensitivity is not an issue, i would get the regular version anyway.

 

[mart34]

Im not really into making youtube movices but thank you . Actually building 4 sealed subs was no rocket science, just a lot of work . Getting all 4 subs to produce flat response at multiple listening positions was the hardest part. But if you spend a lot of time in MSO, you always get it right .


Thats right. And the problem is that the filters start "peaking". However, i can't find any measurements on the HD version of the miniDSP, which is different from the 4x10 version. So i don't know if this issue relates to the miniDSP HD version. But if input sensitivity is not an issue, i would get the regular version anyway.

Totally understand, not everyone wants to put their life on YouTube. I bet is was very hard work, I'm struggling to find the time to make a single enclosure, let alone four !Thanks again for the feedback, appreciated.