Desktop XL - a compact TL for the CSS EL70

Henkjan · 23rd September 2009, 08:49 PM

the design was already mentioned in another thread, but here I want to present it on it's own: Desktop XL.

It is a compact folded TL (the same style TL that I did for the Alpair 5 that was called the desktop TL, this one is a lot bigger, hence the name Desktop XL) that features the new CSS EL70.

desktopXL.jpg
henkjan-DT-TL-EL70-map-300709.pdf

The speaker will play without a notch, but many will appreciate a notch filter to make the sound more neutral. I recommend a simple RCL consisting of a 0.15mH coil, a 1.5ohm resistor, and a 47uF capacitor. the result of this notch can be seen in the measurement below:
EL70 in desktop XL.png
as can be seen, I did not make it completely flat, but left just enough of the extra midrange to give voices that extra presence (I like that in a full ranger). Increasing the value of the resistor to 1.8ohm or 2.2ohm will cure that.

In the drawing (thanks to dave for the artwork) I mention that the distribution of the stuffing is "according to taste". this also has to do with how the box is placed. I have listened mostly to them when standing relatively free, and in that case I have not put any stuffing at all in the open end (so simply 1 mat of Sonofil in the closed end) and was more than happy with the bass. But when on a desktop and/or closer to a wall some damping might be needed.

How do they sound: well on the general qualities of the EL70 much has been said already, it is one fine fullranger, excelent imaging, not hiding details, and good high. and this TL gives it a realy nice bass, not just deep, but with plenty dynamics.

now the only problem I have is where do I put this speaker without my wife freaking out

mus · 24th September 2009, 02:33 AM

About the notch filter!
Are these 3 components connected in series?

Henkjan · 24th September 2009, 07:00 AM

these components are in paralel, and that set is in series with the driver.

mus · 24th September 2009, 07:40 AM

Thanks! This Desktop EL70 will be my next project.

Henkjan · 24th September 2009, 09:42 AM

cool, keep us informed

Rick NL · 24th September 2009, 12:39 PM

Hi HenkJan,
What would your suggestion be to create a version that can be placed with its rear to a wall.
I was thinking of splitting the port in two, one to each side and keeping the total area constant. Or would the wall placement need another alignment?
Rick

Henkjan · 24th September 2009, 09:37 PM

tough one... there is more than just the port to deal with. yr idea with splitting will deal with that. but the general boost of the lower frequencies is a bit harder to predict. I'd expect that adding more stuffing to the open end will in most cases do enough in this area.

Henkjan · 1st October 2009, 08:33 AM

Quote:

Originally Posted by mus

Thanks! This Desktop EL70 will be my next project.

have you started building yet?

mus · 1st October 2009, 09:03 PM

Not yet! I just want to get all the information ready then start it when I have time. Hopefully I can start building it in early next year. Right now I have two projects running, a KT88 SE Amp and a rebuilt of my old EL34 parallel push pull Amp. Thanks for your great box plan and your good help!

Moset · 13th June 2010, 10:42 PM

I just put completed the first of a pair of Desktop XLs. I've been putting off building speakers for quite a while but found these plans and they looked simple enough to build.

Just the one took the weekend (including half a day of buying materials and components) to build. It's the first proper (ie. with actual plans and measurments) speaker I build and initial impressions are, well, really good.

Did a couple of listens with clamps on when the speaker wasn't completely finished and I was sort of disappointed (but knew enough not to judge at that stage). So when I finally played it completely sealed, my jaw dropped squarely on the floor. There was an huge amount of bass in them, and the cone's hardly moving. Now, the bass is a bit boomy, so I've tried stuffing the open end with a few grams of wool (about 10%, as per the instructions), which flattened the bass response but also took away a bit much of it. I just jammed it in the mouth, not wanting to disassemble the driver. Should I plopp it in higher in the funnel instead, or perhaps just use less?

I'll probably not do much more trial-and-error stuffing until I've got the whole pair completed. Right now, I'm just really happy I've a single speaker that already plays the **** out of everything I've previously built (or owned, for that matter). Thanks!

I'll put up pictures from the build in a few days, but now I'll need to get some sleep.

23rd September 2009, 08:49 PM	#1
Henkjan diyAudio Member Join Date: Jan 2006 Location: Berkel en Rodenrijs	Desktop XL - a compact TL for the CSS EL70 the design was already mentioned in another thread, but here I want to present it on it's own: Desktop XL. It is a compact folded TL (the same style TL that I did for the Alpair 5 that was called the desktop TL, this one is a lot bigger, hence the name Desktop XL) that features the new CSS EL70. desktopXL.jpg henkjan-DT-TL-EL70-map-300709.pdf The speaker will play without a notch, but many will appreciate a notch filter to make the sound more neutral. I recommend a simple RCL consisting of a 0.15mH coil, a 1.5ohm resistor, and a 47uF capacitor. the result of this notch can be seen in the measurement below: EL70 in desktop XL.png as can be seen, I did not make it completely flat, but left just enough of the extra midrange to give voices that extra presence (I like that in a full ranger). Increasing the value of the resistor to 1.8ohm or 2.2ohm will cure that. In the drawing (thanks to dave for the artwork) I mention that the distribution of the stuffing is "according to taste". this also has to do with how the box is placed. I have listened mostly to them when standing relatively free, and in that case I have not put any stuffing at all in the open end (so simply 1 mat of Sonofil in the closed end) and was more than happy with the bass. But when on a desktop and/or closer to a wall some damping might be needed. How do they sound: well on the general qualities of the EL70 much has been said already, it is one fine fullranger, excelent imaging, not hiding details, and good high. and this TL gives it a realy nice bass, not just deep, but with plenty dynamics. now the only problem I have is where do I put this speaker without my wife freaking out

24th September 2009, 12:39 PM	#6
Rick NL diyAudio Member Join Date: Sep 2003 Location: Gouda	Back to a wall version? Hi HenkJan, What would your suggestion be to create a version that can be placed with its rear to a wall. I was thinking of splitting the port in two, one to each side and keeping the total area constant. Or would the wall placement need another alignment? Rick __________________ After all it's the music

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24th September 2009, 02:33 AM	#2
mus diyAudio Member Join Date: Mar 2006 Location: bc	About the notch filter! Are these 3 components connected in series?

24th September 2009, 07:00 AM	#3
Henkjan diyAudio Member Join Date: Jan 2006 Location: Berkel en Rodenrijs	these components are in paralel, and that set is in series with the driver.

24th September 2009, 07:40 AM	#4
mus diyAudio Member Join Date: Mar 2006 Location: bc	Thanks! This Desktop EL70 will be my next project.

24th September 2009, 09:42 AM	#5
Henkjan diyAudio Member Join Date: Jan 2006 Location: Berkel en Rodenrijs	cool, keep us informed

24th September 2009, 09:37 PM	#7
Henkjan diyAudio Member Join Date: Jan 2006 Location: Berkel en Rodenrijs	tough one... there is more than just the port to deal with. yr idea with splitting will deal with that. but the general boost of the lower frequencies is a bit harder to predict. I'd expect that adding more stuffing to the open end will in most cases do enough in this area.

1st October 2009, 09:03 PM	#9
mus diyAudio Member Join Date: Mar 2006 Location: bc	Not yet! I just want to get all the information ready then start it when I have time. Hopefully I can start building it in early next year. Right now I have two projects running, a KT88 SE Amp and a rebuilt of my old EL34 parallel push pull Amp. Thanks for your great box plan and your good help!

13th June 2010, 10:42 PM	#10
Moset diyAudio Member Join Date: Jun 2009	I just put completed the first of a pair of Desktop XLs. I've been putting off building speakers for quite a while but found these plans and they looked simple enough to build. Just the one took the weekend (including half a day of buying materials and components) to build. It's the first proper (ie. with actual plans and measurments) speaker I build and initial impressions are, well, really good. Did a couple of listens with clamps on when the speaker wasn't completely finished and I was sort of disappointed (but knew enough not to judge at that stage). So when I finally played it completely sealed, my jaw dropped squarely on the floor. There was an huge amount of bass in them, and the cone's hardly moving. Now, the bass is a bit boomy, so I've tried stuffing the open end with a few grams of wool (about 10%, as per the instructions), which flattened the bass response but also took away a bit much of it. I just jammed it in the mouth, not wanting to disassemble the driver. Should I plopp it in higher in the funnel instead, or perhaps just use less? I'll probably not do much more trial-and-error stuffing until I've got the whole pair completed. Right now, I'm just really happy I've a single speaker that already plays the **** out of everything I've previously built (or owned, for that matter). Thanks! I'll put up pictures from the build in a few days, but now I'll need to get some sleep.

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