Small Scale HT

[Primare Knob]

Ok, I think get it. one last dumb question , so its 50mm maximum thickness or multiple layers?

You can go thicker, but it doesn't really help much. You also have to be careful with going to thick, as it can become counter productive.

I have filled up the empty space in the corners with low density insulation, as this showed better results in measurements, compared to 100mm high density.

[frednork]

1 minute ago, Primare Knob said:

You can go thicker, but it doesn't really help much. You also have to be careful with going to thick, as it can become counter productive.

I have filled up the empty space in the corners with low density insulation, as this showed better results in measurements, compared to 100mm high density.

Ok, interesting! dont have the measurements handy do you?

[Primare Knob]

Ok, interesting! dont have the measurements handy do you?

Not really, but you can use some online acoustics modelling, which show the same effect.

http://www.acousticmodelling.com/multi.php

[frednork]

Nice site, Will have to have a look at the other calculators. 

 

I can see you get higher absorption at certain frequencies with the 50mm but you also will have to deal with the troughs and on average there is slightly less absorption.  . In reality its hard to know what works better unless you try both options and measure (and listen) because you cant put all the details of your room in a calculator. Hmm has made me think about my absorption panels though.....

 

Congrats on a great looking (and I'm sure) sounding room!! and thanks for making me think about this.

[Primare Knob]

Nice site, Will have to have a look at the other calculators. 
 
I can see you get higher absorption at certain frequencies with the 50mm but you also will have to deal with the troughs and on average there is slightly less absorption.  . In reality its hard to know what works better unless you try both options and measure (and listen) because you cant put all the details of your room in a calculator. Hmm has made me think about my absorption panels though.....
 
Congrats on a great looking (and I'm sure) sounding room!! and thanks for making me think about this.

The calculator is using a 0 degree incidence, which isn't accurate in real life. If you switch to a random incidence, you'll see the throughs disappear. Theory and real live often don't add up, so only take this a guideline.

You can see that the throughs happen at every "half length frequency" step of the distance you choose from the wall. Roughly every 340Hz interval with settings of 500mm, which is the half way length of 680Hz aka 500mm.

The front corner of the room has HD(48kg/m3) insulation and LD insulation, and in between (screen and equipment space) there is only 50mm MD (32kg/m3).

I not only covered the front but also the sides and the height with 50mm HD and MD insulation at various distance from the side wall, floor and ceiling.
All absorber start working at frequency X, which is half the frequency of the wavelength related to the distance between wall and absorber.

You have to be carefully in your expectations and reading your measurements. The 500mm distance in my case doesn't do anything for the SPL response below 100Hz, where you need it the most, but the effect does show up in the decay rate and RT60 graphs. Sometimes it also has effect on the group delay if it happens to cure a SBIR effect.

I have mostly used the graphs dealing with decay and group delay regarding treatment. The SPL graph is good for digital EQ, and finding out which effect belongs to which problem.

But I still have lots to learn on measurements myself.

[warweary]

Pretty cool home theatre.

[Tai Huynh]

Very nice room 

 

[elmura]

Hey bud. I designed & built a new home with a big home theatre room and am not happy with the acoustics of the room. There's slap echo and other resonances. And I'm finding the sound localising to be smeared.

Especially considering I've spent quite a bit of money already on equipment & room (with future plans to add another sub, upgrade the surround processor, add ceiling atmos speaker). What methods did you use to work out what & where to place your wall treatments & what insulation products did you use (aside from the mdf sheets)?

 

Also, I'm not clear on what those products are on your ceiling?

 

Thanks

[Primare Knob]

It has taken me some time as I had this planned a lot sooner, but I finally found the time to build my own subwoofers. It has been a nice project, although the bamboo floor boards used for the outer skin has proven to be challenging for my basic tools.

 

The result however is pleasing and more importantly according to plan regarding my goals and expectations. I don’t really know how loud the max is, as I haven’t pushed things to the extreme, but it can reach 115dB at -3dBFS down to 17Hz. Why it is starting to slope down quite rapidly starting at 17Hz I haven’t figured out yet. It slopes down by 8dB rather quick and then start to level out at the SPL when I run a sweep starting at 10Hz.

 

Due to acoustic treatment, sub placement and listen position the non EQ output isn’t too bad, and with a little EQ, I get a nice sloping curve which is +3dB at 20Hz. I haven’t EQ-ed the peak at 140Hz, as I cross over the subs at 80Hz with a 48dB/Octave slope.

My system is tuned to output 80dB at -20dBFS instead of the generic 85dB, as I never listen at 85dB because I find it simply too loud, and usually have the volume control sitting at 75dB.

 

The subs have the external dimension of 440mmx440mmx440mm, and uses timber legs to sit on top of a concrete paver (base) with rubber feet. I find this to work better on a floating floor instead of having them sit directly onto the floor.  I did the same thing for my main speakers.
They are made out of an 18mm MDF inner shell with 3D bracing, and are cladded with a 14mm bamboo flooring outer shell. They are externally powered by a Behringer iNuke power amp, which I still have to modify because the fans inside are too loud for quiet scenes. They weigh about 40KG each without the base.

 

Not sure yet what I want to do with the old subs, as I don’t have any placement options to smooth out the SPL levels, and don’t need the extra output level. I am considering to use them as Subs for bass management for all my other speakers except mains, but I have to do some research to see if there is any benefit in that, as I have to reconfigure my system to a 6.2 setup with 9 speakers. I haven’t tested yet to see if there is a down side to running the surround backs in mono compared to stereo.

 

 

Edited February 24, 2020 by Primare Knob

[Primare Knob]

On 18/02/2020 at 4:17 PM, elmura said:

Hey bud. I designed & built a new home with a big home theatre room and am not happy with the acoustics of the room. There's slap echo and other resonances. And I'm finding the sound localising to be smeared.

Especially considering I've spent quite a bit of money already on equipment & room (with future plans to add another sub, upgrade the surround processor, add ceiling atmos speaker). What methods did you use to work out what & where to place your wall treatments & what insulation products did you use (aside from the mdf sheets)?

 

Also, I'm not clear on what those products are on your ceiling?

 

Thanks

The methods I used are Research, Measurements, Try and Error. All my acoustics are based on the principle of absorption and random reflections (simplified diffusion). If you go about this yourself you need to do research to understand how and what works to which extend, then the best way to go about it is going step by step. Tackle one problem at the time, test-measure-listen-adjust-repeat. My ceiling is just a bunch of timber slats/strips with absorption behind it. You can use any kind of absorption, but the ones which gas flow values are know, are preferred, as you use that in (online) acoustic modeling software to give you rough estimates.

 

The acoustic forum is a good place to start your research as well as google. Your best weapon is to know what works, and why, or what doesn't work and why. There are general treatment ideas for theater rooms which you can use as a starting point, and adjust from there, test-measure-listen-adjust-repeat.

Edit: I forgot about Subwoofer placement and listen position, which can help out a great deal (for free), and some minor EQ at LFE levels where acoustic treatment is difficult.

Edited February 24, 2020 by Primare Knob

[Pops110]

10 hours ago, Primare Knob said:

It has taken me some time as I had this planned a lot sooner, but I finally found the time to build my own subwoofers. It has been a nice project, although the bamboo floor boards used for the outer skin has proven to be challenging for my basic tools.

 

The result however is pleasing and more importantly according to plan regarding my goals and expectations. I don’t really know how loud the max is, as I haven’t pushed things to the extreme, but it can reach 115dB at -3dBFS down to 17Hz. Why it is starting to slope down quite rapidly starting at 17Hz I haven’t figured out yet. It slopes down by 8dB rather quick and then start to level out at the SPL when I run a sweep starting at 10Hz.

 

Due to acoustic treatment, sub placement and listen position the non EQ output isn’t too bad, and with a little EQ, I get a nice sloping curve which is +3dB at 20Hz. I haven’t EQ-ed the peak at 140Hz, as I cross over the subs at 80Hz with a 48dB/Octave slope.

My system is tuned to output 80dB at -20dBFS instead of the generic 85dB, as I never listen at 85dB because I find it simply too loud, and usually have the volume control sitting at 75dB.

 

The subs have the external dimension of 440mmx440mmx440mm, and uses timber legs to sit on top of a concrete paver (base) with rubber feet. I find this to work better on a floating floor instead of having them sit directly onto the floor.  I did the same thing for my main speakers.
They are made out of an 18mm MDF inner shell with 3D bracing, and are cladded with a 14mm bamboo flooring outer shell. They are externally powered by a Behringer iNuke power amp, which I still have to modify because the fans inside are too loud for quiet scenes. They weigh about 40KG each without the base.

 

Not sure yet what I want to do with the old subs, as I don’t have any placement options to smooth out the SPL levels, and don’t need the extra output level. I am considering to use them as Subs for bass management for all my other speakers except mains, but I have to do some research to see if there is any benefit in that, as I have to reconfigure my system to a 6.2 setup with 9 speakers. I haven’t tested yet to see if there is a down side to running the surround backs in mono compared to stereo.

 

 

Amazing mate, that room and subs look spectacular. Well done.

[Primare Knob]

It has been a while since my last update, but I have been playing around with 4 subs, and I turned my 7.2 setup into a 6.4 setup by sacrificing one surround back channel and turn it into a separate sub channel. I setup my main subs for LFE duty, my old subs for Bass Management for all speaker except Left and Right, and  turned my back surround speakers into two mono speakers.

 

I did set it up in such a way so that I could switch between my 6.4 setup and 7.2 setup for comparison. The extra subs do bring extra weight to the show, but this can also be achieved by dialing up the subs by +6dB. As long as the subs have the headroom to do this I could not pick one from the other reliably. Turning the back surrounds into two mono speakers did have more impact then anticipated.

With sound effects, I could pick one over the other if I really tried, but nothing that would spoil the soundtrack, or would be picked up while watching a movie, but the thing that always stood out in the 6.4 setup where the ambient sounds. They would pop out more and rather spoil the effect of the soundtrack.

 

Since I listen at -12.5 dBFS below reference, my subs have the headroom to be dialed up a bit more, and I am not a big fan of to much bass anyway so I have reverted back to the 7.2 setup again. I am limited to 8 channels at the moment which suite my purpose just fine. The other thing that I found during testing, and only listening to sub bass, was that frequencies below 20Hz are rather unpleasant to listen to, and cause quite a bit of pressure on the ears. I am now rolling off my subs with a rather steep slope down from 17Hz, as I could not distinguish the difference between any of the tones lower than that. This has planted the idea to introduce some bass shakers in the future, but this would require an additional cross over or adding some extra channels to the DA converter.

[:) Go Away (:]

What DA/AD convertor are you using? So, if I understand correctly, you have HTPC which is connected to DA/AD converter for audio out to amps and HDMI graphics card for video out to TV/Screen?

 

That is a neat HT Room. Very impressive.

[Primare Knob]

7 hours ago, :) Go Away (: said:

What DA/AD convertor are you using? So, if I understand correctly, you have HTPC which is connected to DA/AD converter for audio out to amps and HDMI graphics card for video out to TV/Screen?

 

That is a neat HT Room. Very impressive.

Thanks. You have got that correct idea about my setup.

 

I am using a Lynx Aurora N 8 channel AD/DA converter for the following reasons;

- It can handle up to 16 channels via USB (No additional equipment needed)

- It is expendable up to 32 channels via input modules

- It has a hardware switch to output at +4dBU (pro audio) or at -10dBV (hifi) (good for level matching with different Power Amp input sensitivities)

- Hifi quality DA converter (compared it with my Bryston BDA-2 )

- Good amount of output voltage

- Can make recordings via USB onto SD-Card (fun to have bonus)

 

 

[:) Go Away (:]

20 minutes ago, Primare Knob said:

Thanks. You have got that correct idea about my setup.

 

I am using a Lynx Aurora N 8 channel AD/DA converter for the following reasons;

- It can handle up to 16 channels via USB (No additional equipment needed)

- It is expendable up to 32 channels via input modules

- It has a hardware switch to output at +4dBU (pro audio) or at -10dBV (hifi) (good for level matching with different Power Amp input sensitivities)

- Hifi quality DA converter (compared it with my Bryston BDA-2 )

- Good amount of output voltage

- Can make recordings via USB onto SD-Card (fun to have bonus)

 

 

Thank you for the information. I had the similar thought but didn't know of AD/DA convertor, in fact I started out building my HTPC but it ended up being Really really really expensive home server. 

I will have to look back into that. Would you say this is a better solution than AVR or Pre/Pro? Rest I would assume is being handled at software level.

[Primare Knob]

1 hour ago, :) Go Away (: said:

Thank you for the information. I had the similar thought but didn't know of AD/DA convertor, in fact I started out building my HTPC but it ended up being Really really really expensive h

 

ome server. 

I will have to look back into that. Would you say this is a better solution than AVR or Pre/Pro? Rest I would assume is being handle

 

 

 

1 hour ago, Go Away said:

Thank you for the information. I had the similar thought but didn't know of AD/DA convertor, in fact I started out building my HTPC but it ended up being Really really really expensive h

 

ome server. 

I will have to look back into that. Would you say this is a better solution than AVR or Pre/Pro? Rest I would assume is being handle

My reasons for walking down this path had to do with the lack of SQ, high depreciation values, over abundance of useless functions and other things that I didn't need.

 

I firmly believe I have better sound quality (for less money), the pro DAC and the 2 channel amps will hold their value better, and I have all the functionality that I need.

 

It also comes with a few caveats. You can't decode Atmos or DTS-X on a PC, it is not the type of setup that is easy for the rest of the family (turning things on and off requires some attention, and your main setup is a PC ), I don't have any inputs (although I could route the AD from the DAC through the PC and out to the DA again), there is no automatic setup for EQ (unless you want to spends some big dollars on software), and component matching is more important than in your general setup as impedance ratios can impact SQ.

 

The benefit is that you have a lot of freedom and that you can do all sorts of things in the digital domain with heaps of digital headroom.

 

I am not sure which road you took previously, but a simple PC can be used as your HT-PC, I think that Parametric EQ isn't heavy to run.

 

[:) Go Away (:]

13 hours ago, Primare Knob said:

 

 

 

My reasons for walking down this path had to do with the lack of SQ, high depreciation values, over abundance of useless functions and other things that I didn't need.

 

I firmly believe I have better sound quality (for less money), the pro DAC and the 2 channel amps will hold their value better, and I have all the functionality that I need.

 

It also comes with a few caveats. You can't decode Atmos or DTS-X on a PC, it is not the type of setup that is easy for the rest of the family (turning things on and off requires some attention, and your main setup is a PC ), I don't have any inputs (although I could route the AD from the DAC through the PC and out to the DA again), there is no automatic setup for EQ (unless you want to spends some big dollars on software), and component matching is more important than in your general setup as impedance ratios can impact SQ.

 

The benefit is that you have a lot of freedom and that you can do all sorts of things in the digital domain with heaps of digital headroom.

 

I am not sure which road you took previously, but a simple PC can be used as your HT-PC, I think that Parametric EQ isn't heavy to run.

 

I bet that does sound better than usual AVR and Pre/Pro, but definitely not a user friendly solution. I was initially thinking the PCI sound card solution for audio out in htpc but that didn't seem like a quality solution, so abandoned the idea and instead ended up building home server. Which ended up being lot more expensive than what I had initially set out to do due to the storage used and choice of CPU to support it.

 

If you look at the Trinnov Pre/pro's back, it looks like a pc with added cards for audio and video.

[Primare Knob]

3 hours ago, :) Go Away (: said:

I bet that does sound better than usual AVR and Pre/Pro, but definitely not a user friendly solution. I was initially thinking the PCI sound card solution for audio out in htpc but that didn't seem like a quality solution, so abandoned the idea and instead ended up building home server. Which ended up being lot more expensive than what I had initially set out to do due to the storage used and choice of CPU to support it.

 

If you look at the Trinnov Pre/pro's back, it looks like a pc with added cards for audio and video.

The Trinnov is a PC with an ATMOS and DTS-X (expensive) license.

 

It doesn't harm to have a good quality CPU in your home server. If you have to do transcoding (especially with subtitles) it will cost some resources. I store full BD copies on the server but run a ChromeCast for the TV, which needs transcoding.

Storage definitely cost you, certainly if you run a full back up as well. My home server (and backup) have 14TB each, and I am thinking about once that is full, to skip back up and use the BD discs as backup and just keep an up to date database only back up. The good thing is that the back up PC doesn't have to be expensive and can be run with old hdd's as they are hardly used. Gumtree and hard rubbish are your friends. All of my hardware is old stuff, and at least 8 years old or hanging together with mixed bits and pieces, except for my gaming Graphics Card.

[:) Go Away (:]

1 hour ago, Primare Knob said:

The Trinnov is a PC with an ATMOS and DTS-X (expensive) license.

 

It doesn't harm to have a good quality CPU in your home server. If you have to do transcoding (especially with subtitles) it will cost some resources. I store full BD copies on the server but run a ChromeCast for the TV, which needs transcoding.

Storage definitely cost you, certainly if you run a full back up as well. My home server (and backup) have 14TB each, and I am thinking about once that is full, to skip back up and use the BD discs as backup and just keep an up to date database only back up. The good thing is that the back up PC doesn't have to be expensive and can be run with old hdd's as they are hardly used. Gumtree and hard rubbish are your friends. All of my hardware is old stuff, and at least 8 years old or hanging together with mixed bits and pieces, except for my gaming Graphics Card.

Well, I wanted a completely silent server so opted for all the non mechanical parts costing bit more than it should have been.

 

AMD Threadripper 1900x for more PCIe lanes with liquid cooling.

64GB Ram.

12 TB of PCIe NVME Storage. (This blew out the cost).

I have couple of 10tb hdds on separate server for backup. 

 

Idea was to use this as all in one server (NAS, Media Server, HTPC) but audio out stopped me, and right now it just serves as glorified NAS server. For now, with the life I have left it as is but in future do intend to do exactly what you have done. I may reach out to you in future for some pointers. 

[Guest Peter the Greek]

On 15/08/2019 at 5:29 PM, Primare Knob said:

Pro Audio multichannel AD/DA converter 

This still intrigues me. I love the idea of ditching a processor. Can you please tell me what the brand/model of the DAC is?

[Satanica]

On 27/06/2020 at 7:52 AM, Peter the Greek said:

I love the idea of ditching a processor.

I did that quite some time ago but I needed a video switcher/matrix and I really like this one which has been working well: https://www.blustream.com.au/cmx42ab

 

And at around $400 makes pretty good value.

 

Edited July 1, 2020 by Satanica

[Primare Knob]

On 27/06/2020 at 8:22 AM, Peter the Greek said:

This still intrigues me. I love the idea of ditching a processor. Can you please tell me what the brand/model of the DAC is?

 

On 15/06/2020 at 5:29 PM, Primare Knob said:

Thanks. You have got that correct idea about my setup.

 

I am using a Lynx Aurora N 8 channel AD/DA converter for the following reasons;

- It can handle up to 16 channels via USB (No additional equipment needed)

- It is expendable up to 32 channels via input modules

- It has a hardware switch to output at +4dBU (pro audio) or at -10dBV (hifi) (good for level matching with different Power Amp input sensitivities)

- Hifi quality DA converter (compared it with my Bryston BDA-2 )

- Good amount of output voltage

- Can make recordings via USB onto SD-Card (fun to have bonus)

 

 

The DA converter can be any brand, but not all brands support multichannel USB, even if the DAC support USB which could be limited to stereo only, and a company with a good track record on stable drivers would be preferred.  You can always use a different connection like AES/EBU via PCIe which many support but this will add to the cost. It is also nice to keep extension in mind if you looking for more channels, which pro audio converters are better equipped for. Do keep in mind that pro audio works with a +4dBU signal which will result in higher default voltages than the consumer -10dBV.

 

There is also the option of using a multichannel PCIe audio card, but I would look for independent measurements to see how they fare.

 

Ideally you want to look for the (best) DA converter that can give you the most digital headroom above 16bit(CD quality) The best will peak between 20-21 bits of dynamic range which will give you 4-5 bits of headroom or 24-30dB of attenuation. This can be managed for example by using dither and or up scaling and in how DSP is implemented and which bits are effected, but the exact workings are beyond my understanding. This will come in play when you have powerful amplifiers, and or high efficiency speakers and or sitting at a close distance.

[Primare Knob]

1 hour ago, Satanica said:

I did that quite some time ago but I needed a video switcher/matrix and I really like this one which has been working well: https://www.blustream.com.au/cmx42ab

 

And at around $400 makes pretty good value.

 

What are you using this for?

[Satanica]

6 hours ago, Primare Knob said:

What are you using this for?

As a HDMI 2.0 Matrix for two sources (HTPC, Foxtel IQ4) and two displays (TV, Projector).

[Primare Knob]

18 hours ago, Satanica said:

As a HDMI 2.0 Matrix for two sources (HTPC, Foxtel IQ4) and two displays (TV, Projector).

Ah, that is before Foxtel was doing online streaming. I suppose you would be able to run a dual output from PC to projector and TV.

 

I haven't run into anything yet that I couldn't do on the PC, although streaming services sometimes don't enable surround sound on their web applications.