The build of the Heissmann Acoustics DXT-MON

[egellings]

They are beautiful. Is the cone on the side of the cabinet driven or is it a passive radiator?

 

[somebodyelse]

They are beautiful. Is the cone on the side of the cabinet driven or is it a passive radiator?

Passive radiator. There's a variant using a reflex port instead.

 

[EXIF68]

If somebody is asking about "how does it sound":
I have tried a recording with an "Voice Recorder Oly LS-P4" on listening position in my room. The track is common known and so you can imagine a little bit about the sound.
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The problem is:
The recording is not as good as it shoudl be. Noisy, the bass level is too boomy (compared to the real situation), too less resolution in the middles and so on. But compared to some other trials about sound recording on yt, i think its not so bad at all. So enjoy and thell me what you think about this trial.

Greetings, Walter

 

[Grotti]

If somebody is asking about "how does it sound":
I have tried a recording with an "Voice Recorder Oly LS-P4" on listening position in my room. The track is common known and so you can imagine a little bit about the sound.
Datei von filehorst.de laden
The problem is:
The recording is not as good as it shoudl be. Noisy, the bass level is too boomy (compared to the real situation), too less resolution in the middles and so on. But compared to some other trials about sound recording on yt, i think its not so bad at all. So enjoy and thell me what you think about this trial.

Greetings, Walter

Just downloaded it and listened on the mobile phone: impossible to evaluate the sound this way. Will give it a try this evening with HP.

Anyway: thank you very much for your effort!

 

[EXIF68]

Here is another song. This one is recorded without the subwoofer. So only the DXT-MON´s only.
Enjoy.
Datei von filehorst.de laden
as mentioned above, the sound quality is not direct comparable to the listening direct to the speakers. the LS-P4 is recording too loud in the base and a lot of details are missing. But better than nothing.

Greetings, Walter

 

[andymok]

try swapping the L & R and let the sub facing out

 

[BostonJack]

Super post, most enjoyable and interesting, I would bet your English is very much better than most people here's German.
Bravo

Super post, congrats on this build. I am late to this party, but I'm getting ready to start my build of DXT-MON next month. I believe that the material I am going to use with the Butyl damping layers is called (American English): tempered hardboard.

Stable, easy to procure.

I do have a question:
Do you believe that the rear of cabinet removable access is necessary? If I use captured backing fasteners, either the woofer or passive radiator provide a large aperture into the cabinet. As a practical matter, this reduces the cabinet complexity a great deal.

Thanks!

 

[EXIF68]

Hello,
the cut out in the back side is very comfortable for integrating the comparable big cross board but necessary is this opening definitely not. You have the opening from the bass driver and also the passive radiator and enough space to do this work. I have ordered the cabinets from a cnc manufacturer and so the cost impact was not huge for the opening on back side and the rear panel is adiitinally chamfered 45 degrees to fit perfectly to the other parts. There is no gap or other things visible, perfect wood work still after a lot of months.

greetings, Walter

 

[BostonJack]

Hello,
the cut out in the back side is very comfortable for integrating the comparable big cross board but necessary is this opening definitely not. You have the opening from the bass driver and also the passive radiator and enough space to do this work. I have ordered the cabinets from a cnc manufacturer and so the cost impact was not huge for the opening on back side and the rear panel is adiitinally chamfered 45 degrees to fit perfectly to the other parts. There is no gap or other things visible, perfect wood work still after a lot of months.

greetings, Walter

Walter,
Thank you! I'll pay attention to the crossover size and those driver holes. Thank you for confirming my guess.
Jack

 

[Vavilen]

Next step was sanding the cabinets and giving them the last "outfit" with a special furniture oil. This oil gives a good lock to the veneer and is really easy to handle. no problems with lacquer noses and such things.
After oiling sanding with 1000-Paper and oiling again... several times. all together 6 layers including polishing

Hi @EXIF68 ! Looks amazing!
I've the same cabinets. How is it going 2 years since you oiled yours.
Would you recommend to use the same technique with 6-layers of furniture oil?
Thanks!

 

[EXIF68]

Hello Vavilen,

my cabinets are in the same condition as two years ago. No change in wood behavior or else. The color was getting a little bit darker but they are still looking good. The surface quality is also very stable.
one point I forget to mention above: I have stored the raw housing materials for several months in the music room before gluing and finishing. Enough time for perfect wood humidity.
my cabinets have only a few layers of oiling. 6 layer furniture oil would be not too bad at all. Try it.
The best about this speakers: they still sounding very, very fine. Perfect for such low expensive systems.

greetings, Walter

 

[NiagaraPete]

Very nice! I always envy you guys that can do really good woodwork. That's a talent that escapes me.

I fall into that category as well.

 

[Vavilen]

Hello Vavilen,

my cabinets are in the same condition as two years ago. No change in wood behavior or else. The color was getting a little bit darker but they are still looking good. The surface quality is also very stable.
one point I forget to mention above: I have stored the raw housing materials for several months in the music room before gluing and finishing. Enough time for perfect wood humidity.
my cabinets have only a few layers of oiling. 6 layer furniture oil would be not too bad at all. Try it.
The best about this speakers: they still sounding very, very fine. Perfect for such low expensive systems.

greetings, Walter

Hi Walter!
Could you please explain how have you mounted the crossover boards?
Was it on the bottom side using screws?
Or shall I screw into the cabinets something like this and then use screws?

Maybe, you have some photos?

Thanks in advance!

 

[EXIF68]

Hello,
the crossover network on my system is mounted on a 4mm epoxy boards, size adustet to fit on the back wall inside the cubicle. I have no detailed pictures from the mounting process, but I think you can imagine it. The epoxy boards are mounted with wood screws and 1cm distant rolls so that there is no tension on the mounted components.
the coils are fixed with M4 brass screws (worm holes done by 3,2mm drilling’s and M4 stew taps). This works fine in 4mm epoxy boards and capacitors, resistors are fixed with cable ties on the board as well. wired together by soldering the connecting wires together, additional use of 1,5mm2 massive Silver coated Cu wire. Connections are done by brass screw terminals on the epoxy boards.
greetings,
Walter

 

[EXIF68]

Here on this picture you see the back wall, on top a little bit of the crossover Board.
„FW“ means „Frequenzweiche“ or crossover board. The terminals are mounted nearby „unten“ directly in the wood.

 

[Vavilen]

Hello,
the crossover network on my system is mounted on a 4mm epoxy boards, size adustet to fit on the back wall inside the cubicle. I have no detailed pictures from the mounting process, but I think you can imagine it. The epoxy boards are mounted with wood screws and 1cm distant rolls so that there is no tension on the mounted components.
the coils are fixed with M4 brass screws (worm holes done by 3,2mm drilling’s and M4 stew taps). This works fine in 4mm epoxy boards and capacitors, resistors are fixed with cable ties on the board as well. wired together by soldering the connecting wires together, additional use of 1,5mm2 massive Silver coated Cu wire. Connections are done by brass screw terminals on the epoxy boards.
greetings,
Walter

Hi Walter!
Thank you so much for such a detailed explanation

 

[DaveFred]

Do you recall what this angle is?

 

[EXIF68]

I must not recall , I can measure it: exactly 27 Degrees.

greetings, Walter

 

[DaveFred]

I must not recall , I can measure it: exactly 27 Degrees.

greetings, Walter

Thank you, David.

 

[Capitol C]

Yeh, that's to be expected. The added mass reduces both the frequency and SPL of the output passive radiator's output.

There's no right or wrong here, just different system Q.

One thing, though, is that if you're measuring in the nearfield, you need to take into account that the passive membrane has a larger radiating surface than the woofer. So you need to scale the measurements by the square roots of the radiating diameters.

In this case, your woofer's Sd is 93cm^2 and your passive radiator's Sd is 130cm^2, which implies that their diameters are approximately 10.9cm and 12.9cm, respectively.

If we take the square roots of the diamters we get about 3.3 for the woofer and 3.6 for the passivate radiator, which means that, for the graphs to be more accurate, you should increase the plot amplitude of the passive radiator by a factor of 3.6/3.3 = 1.09 (approxmitately).

Of course, that will not take into account baffle step. But it will at least allow you to display the measurements for the passive radiator and the woofer more accurately in relation to each other (and should bring the passive radiator's peak up closer to the woofer's output level).

Having said all of that, you're going to be listening to this speaker in your room, and the room will be the main factor in determining the bass response. So you may as well choose the passive radiator tuning that works best in your room.

A question from ignorance: why is it the square root? I would have made a guess that it went like the area, ie, the square of the radius.