Fullrange speaker project based on Morel TSCM 634

[ppataki]

I would like to share another DIY project but this is a finished one so I can provide all the measurement diagrams as well

I wanted to have a fairly decent fullrange system in my home office and I had a spare pair of Morel TSCM 634 drivers so I thought why not use them for a good purpose...
The idea was to build relatively small closed cabinets that will be attached to the front wall with a wall mount instead of putting them on my desk.

So the cabinet is closed with a volume of approx. 8 liters and with a Qtc =0.707 made of 21mm thick plywood except for the fronts that are 42mm thick

And that is how they look like in the room (the room is totally untreated!)

They are driven by a Loxjie A30 DAC+Amp that was bought for this project based on Amirm's review here (Many Thanks for that!)
USB cable is Supra, speaker cables are Sommer Orbit 240 MK2 (also used inside the speakers)

The listening triangle is 86cm (equilateral)

The below REW measurements were made at listening position with Dirac Live 3 and Pultec EQ (Waves); the latter to match the amount of lows and the highs to my personal taste/preference (so the tilt at the two ends are made to taste and can be freely modified)

Frequency response (1/12) with Excess Phase
The dips are all room modes and cannot be corrected with Dirac or any EQ

Step Response:

Impulse response:

Excess Group Delay:

Waterfall:

Wavelet:

Overall I am really satisfied with the results, the sound is enjoyable with great dynamics and low-end (compared to the fact that I am using 6" drivers)
Dirac does a great job with all the optimizations as always
What I love about all these one-way fullrange systems is the "live" sound experience that is probably due to the fact that there is no crossover whatsoever involved.

Any comments/questions are welcome; I hope you find this useful for your own projects

 

[tomelex]

yes, great review of your project, thanks for that. and yes, the imaging is typically better with systems such as yours, and also actually less highs as well also help, most of that junk up above 12K in reproduction (as opposed to real life) just seems to mess things up. You are a good candidate for a SET system buddy!

 

[LTig]

How would FR look without an EQ?

 

[ppataki]

yes, great review of your project, thanks for that. and yes, the imaging is typically better with systems such as yours, and also actually less highs as well also help, most of that junk up above 12K in reproduction (as opposed to real life) just seems to mess things up. You are a good candidate for a SET system buddy!

Thank you, I appreciate that
What is a SET system?

 

[ppataki]

How would FR look without an EQ?

As awful as any other one-way system
I will post them tomorrow

 

[tomelex]

Thank you, I appreciate that
What is a SET system?

single ended triode, a very simple, very short signal path amplifier using tubes, the 300B output tube being most popular. It goes with the simplicity of your speaker set up, but is low power so you can not get high sound pressure levels. Since you are so handy with your DIY, you can build one yourself if you desire.

 

[ernestcarl]

I would like to share another DIY project but this is a finished one so I can provide all the measurement diagrams as well

I wanted to have a fairly decent fullrange system in my home office and I had a spare pair of Morel TSCM 634 drivers so I thought why not use them for a good purpose...
The idea was to build relatively small closed cabinets that will be attached to the front wall with a wall mount instead of putting them on my desk.

So the cabinet is closed with a volume of approx. 8 liters and with a Qtc =0.707 made of 21mm thick plywood except for the fronts that are 42mm thick

View attachment 151294
View attachment 151295

View attachment 151296

And that is how they look like in the room (the room is totally untreated!)

View attachment 151297

They are driven by a Loxjie A30 DAC+Amp that was bought for this project based on Amirm's review here (Many Thanks for that!)
USB cable is Supra, speaker cables are Sommer Orbit 240 MK2 (also used inside the speakers)

The listening triangle is 86cm (equilateral)

The below REW measurements were made at listening position with Dirac Live 3 and Pultec EQ (Waves); the latter to match the amount of lows and the highs to my personal taste/preference (so the tilt at the two ends are made to taste and can be freely modified)

Frequency response (1/12) with Excess Phase
The dips are all room modes and cannot be corrected with Dirac or any EQ
View attachment 151298


Step Response:
View attachment 151299

Impulse response:
View attachment 151300

Excess Group Delay:
View attachment 151301

Waterfall:
View attachment 151302

Wavelet:
View attachment 151303

Overall I am really satisfied with the results, the sound is enjoyable with great dynamics and low-end (compared to the fact that I am using 6" drivers)
Dirac does a great job with all the optimizations as always
What I love about all these one-way fullrange systems is the "live" sound experience that is probably due to the fact that there is no crossover whatsoever involved.

Any comments/questions are welcome; I hope you find this useful for your own projects

Very nice! I wish I could "build" my own monitors... the only one-way monitor that I have is my small Fostex 6301 -- but I can't exactly call music listening to it a "live" sound experience -- but very much still love it!

Hmmmn... Despite raising the moinitors and attaching it directly to the wall, though, the desk is huge enough that I do expect SBIR from it to be much more visible in the "raw" unequalized response. Maybe possibly like that 400-500Hz peak & dip? Just a guess.

 

[LTig]

A heavily EQed speaker needs more power than a SET amp could possibly deliver. Most of these amps belong to the "distortion generator" category anyway which is not what most people would recommend here at ASR.

 

[DownUnderGazza]

Can I suggest a wee experiment?

Find some polystyrene or styrofoam or similar rigid but light material, often found in packaging.
And add 'wings' to your speaker. Try either side and on top if you have enough material.

Two options come to mind.

• One is to create a 'wide' baffle to help lower the baffle step droop in the response. It will also smooth out edge diffraction ripples as well. You'll get more mid bass (typically 300-100hz) and thus require less amplifier oomph. This is the easiest to do as it's a simple flat surface with a cutout to match the baffle. The bigger the better. When done it can be slipped in place in moments.
• The second option is to add 50mm / 2" rounded edges, flush with the baffle front surface, to smooth any edge diffraction that arises when you have hard and sharp edges. This is more fiddly, but should also be able to be slipped into place in seconds.

Then run DIRAC correction over it and see what the result looks like. Give yourself a saved preset for each configuration so you can easily switch between the correction curves depending on which set of wings have been added.
More importantly, see if you can hear any differences either of these additions might make.

 

[ppataki]

Here is the uncorrected FR vs. corrected FR

I have had several DIY fullrange systems and it is pretty clear that these must be heavily corrected, otherwise they are practically unlistenable
(especially my 12" system in my living room)
But once properly corrected, the results are unbeatable (at least to my taste, totally subjectively)

 

[LTig]

Looks better than expected. But up to 13 dB EQ increase in the bass is quite a lot.

 

[abdo123]

Step response is janky, did you damp the cabinet?

 

[ppataki]

In the first photo you can see the damping; I was using polyester fiber: https://www.soundimports.eu/en/monacor-mdm-2.html
That is what I usually use with my full-range projects

 

[abdo123]

In the first photo you can see the damping; I was using polyester fiber: https://www.soundimports.eu/en/monacor-mdm-2.html
That is what I usually use with my full-range projects

this doesn't really do anything for low frequencies, i would use plywood for the cabinets instead of MDF or other less stiff woods and in between two layers of plywood i would put Sorobothane (if you're fancy) or Decidamp if you want it to be more affordable.

https://www.pyroteknc.com/products/decidamp/decidamp-dc30/

 

[ppataki]

Thank you for the tip!
Just for my development, can you send a reference measurement how the step response shall look like? (so I would know what to aim for)
Or at least describe how it shall look like

 

[abdo123]

Thank you for the tip!
Just for my development, can you send a reference measurement how the step response shall look like? (so I would know what to aim for)
Or at least describe how it shall look like

Sorry i meant the impulse response! The picture below should show you how we can determine how quickly direct sound decays from an impulse response. In your figure it's difficult to tell where direct sound settles down and where room reflections kick in, this could be because the cabinet is resonating so direct sound never really decays before room reflections arrive. If you're not applying any damping to the cabinet then the overall mass and stiffness might too low to stop the cabinet from bending and producing sound outside the cabinet. Generally you want to use a plywood sandwich with a layer of damping material in the middle. This is really one of the things that makes the difference between an amateur speaker and a professional one.

 

[tomelex]

A heavily EQed speaker needs more power than a SET amp could possibly deliver. Most of these amps belong to the "distortion generator" category anyway which is not what most people would recommend here at ASR.

You can see that I have been on this site since 2016, almost at its founding, so I do know a bit about what the site is all about. Since the OP agrees with you (without even knowing what a SET amp was to start with) I will say no more in this thread about SET amps. However, one day the OP may sing a different tune, as absolute pure reproduction of audio in a two channel system does not always equate to a "preferred" sound by many folks. And the room and the speaker interaction and the speakers themselves are big distortion generators even with SET gear, of course.

 

[abdo123]

I found the video that i remember learning first about cabinet damping from, it has a lot of useful information about speaker design and building in general, hope you find it interesting.

 

[ppataki]

What about using a 1-2 mm thick silicone or SBR panel between the two layers of plywood?

 

[ppataki]

Also when searching for viscoelastic damping I found two things that might work:

- 3M SJ2040X
- Green Glue Noiseproofing Compound

I can get these in Europe too

Btw. memory foam is also made of viscoelastic material....I wonder what would happen if I put a 2cm memory foam layer between the plywood layers....