Cable Modems

Apr 17, 2019
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#1
I wanted to share some cable modem experence.

As far as how a cable modem sounds and a router sounds I assume the discussion is about streaming ? Because if a "clean" switching setup for audio is done correctly, like below, the router and modem are galvanically isolated by optical from the clean setup and so zero packets go outside the clean network and there is zero RF -- like in the below example.

For example:
Taiko > SoTM > SoTM>DAC with the SoTMs ext clocked. The SoTMs are fed by linear supplies and optical from Taiko and between switches. Optical to router located in a different room.

So.. Modems.. It turns out I am kinda a expert on cable modems. There are only 2. EVERY modem in the market is based on either Broadcom or Intel. Each company produces a hardware reference that is then used by all the CPE makers like Arris, Netgear, etc.. You crack these open and these devices are remarkably the same. YES how they implement power supply differs in LAYOUT and SOME config, but, mostly its the same across all mfgrs of a modem chip. So crack open a Arris SB8200 and a Netgear CM1000 and you will find exactly the same parts, with the same part numbers, located in about the same places. So GENERALLY these devices are nearly carbon copies but with different packaging and sometimes more ports. What REALLY counts tho is what chip. Intel based modems are HORRENDOUS in jitter. Class action lawsuits, news reports. This site has details and what CPE models are based on this Intel chip. http://badmodems.com/

So.. Intel based devices should NEVER be used. This means Broadcom devices are where its at. DOCSIS 3.1 modems have OFDM modulation and a cable co usually combines a 32 QAM modulated channels with a OFDM stream. This combo produces a much cleaner ( less jitter, less retransmissions ) then DOCSIS 3.0 modems from a few years back.. Also these DOCSIS 3.1 modems can be set up with Link Aggregation to a good router. This *might* be good as other house traffic might find a way thru the device without disturbing the audio flow as much.

So I would assume a DOCSIS 3.1 modem is the best for audio... Broadcom being the only one to consider.

Now which brand ? Well,, one of the first thing to know about buying your own cable modem is that many cable companies do not firmware update customer owned gear. Trust me, you want firmware updates. You CANNOT do this on your own. Its important to find out if your cable co does firmware updates for customer owned equipment. If it does, which models. Just because it says it will work on the Cable Co web site DOES NOT MEAN they will firmware update it. If you pick a modem that is also used by your cable co, they will most likely update it.

A good universal is the Arris SB8200. This is the most widely deployed modem. Its got good firmware support. Its broadcom based. Its supports Link Aggregation.

Ive been stuffing in GIANT caps into modems for 10 years to get better jitter and more stable performance. Not for audio, just for networking performance. I also have been using a linear supply on my modems for forever. I put huge tantalum caps on the chip power rails. I use audiophile caps pre regulation. A good no noise fan is a VERY good idea. I even put more stable clocks in.. None of this was for audio, BUT, would obviously help audio.. MAYBE..

For a router I prefer a https://mikrotik.com/product/CCR1036-8G-2SplusEM with a linear supply and lots of caps. This has a brute force to not jitter at all under load. It has s SFP+ ports which makes it easy to feed a clean networking setup.

So as far as modems go,, I am throwing in my experence on this, but, how this relates to audio performance, I do not know.
 
Last edited:

matthias

Active Member
Mar 14, 2019
318
96
28
Germany
#2
I wanted to share some cable modem experence.

As far as how a cable modem sounds and a router sounds I assume the discussion is about streaming ? Because if a "clean" switching setup for audio is done correctly, like below, the router and modem are galvanically isolated by optical from the clean setup and so zero packets go outside the clean network and there is zero RF -- like in the below example.

For example:
Taiko > SoTM > SoTM>DAC with the SoTMs ext clocked. The SoTMs are fed by linear supplies and optical from Taiko and between switches. Optical to router located in a different room.

So.. Modems.. It turns out I am kinda a expert on cable modems. There are only 2. EVERY modem in the market is based on either Broadcom or Intel. Each company produces a hardware reference that is then used by all the CPE makers like Arris, Netgear, etc.. You crack these open and these devices are remarkably the same. YES how they implement power supply differs in LAYOUT and SOME config, but, mostly its the same across all mfgrs of a modem chip. So crack open a Arris SB8200 and a Netgear CM1000 and you will find exactly the same parts, with the same part numbers, located in about the same places. So GENERALLY these devices are nearly carbon copies but with different packaging and sometimes more ports. What REALLY counts tho is what chip. Intel based modems are HORRENDOUS in jitter. Class action lawsuits, news reports. This site has details and what CPE models are based on this Intel chip. http://badmodems.com/

So.. Intel based devices should NEVER be used. This means Broadcom devices are where its at. DOCSIS 3.1 modems have OFDM modulation and a cable co usually combines a 32 QAM modulated channels with a OFDM stream. This combo produces a much cleaner ( less jitter, less retransmissions ) then DOCSIS 3.0 modems from a few years back.. Also these DOCSIS 3.1 modems can be set up with Link Aggregation to a good router. This *might* be good as other house traffic might find a way thru the device without disturbing the audio flow as much.

So I would assume a DOCSIS 3.1 modem is the best for audio... Broadcom being the only one to consider.

Now which brand ? Well,, one of the first thing to know about buying your own cable modem is that many cable companies do not firmware update customer owned gear. Trust me, you want firmware updates. You CANNOT do this on your own. Its important to find out if your cable co does firmware updates for customer owned equipment. If it does, which models. Just because it says it will work on the Cable Co web site DOES NOT MEAN they will firmware update it. If you pick a modem that is also used by your cable co, they will most likely update it.

A good universal is the Arris SB8200. This is the most widely deployed modem. Its got good firmware support. Its broadcom based. Its supports Link Aggregation.

Ive been stuffing in GIANT caps into modems for 10 years to get better jitter and more stable performance. Not for audio, just for networking performance. I also have been using a linear supply on my modems for forever. I put huge tantalum caps on the chip power rails. I use audiophile caps pre regulation. A good no noise fan is a VERY good idea. I even put more stable clocks in.. None of this was for audio, BUT, would obviously help audio.. MAYBE..

For a router I prefer a https://mikrotik.com/product/CCR1036-8G-2SplusEM with a linear supply and lots of caps. This has a brute force to not jitter at all under load. It has s SFP+ ports which makes it easy to feed a clean networking setup.

So as far as modems go,, I am throwing in my experence on this, but, how this relates to audio performance, I do not know.
Hi Xymox,

thanks for your input.

My ISP offers me a DOCSIS 3.1 compatible modem/router from Arris, it is a TG3442DE.

Please, can you share some info about it?

Can you recommend this device?

Thanks again.

Matt
 
Last edited:
Apr 17, 2019
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#3
My ISP offers me a DOCSIS 3.1 compatible modem/router from Arris, it is a TG3442DE.

Please, can you share some info about it?

Regretfully, this is a Intel Puma based device. So this is to be avoided as it induces huge amounts of jitter. http://en.techinfodepot.shoutwiki.com/wiki/Arris_TG3442

Sorry for the bad news..

What you want is a modem separate from the router. No modem+router+wifi+Phone all in one box is good. You need a modem separate and then a powerful router.

In high performance home network ( audio aside ) you want a DOCSIS 3.1 modem. Then you want a serious router that can ACTUALLY do 1Gbps with small packets and a firewall + NAT. Doing 1Gbps in this real life use is WAY beyond consumer routers. In small sized packets its common to see single core routers for consumer use barely get 10Mbps with small packets THRU the router. With a 36 core CPU you barely get over the 1Gbps speeds. So it takes a 36 core CPU to get 1Gbps ethernet "wireline speeds", that means the router does not slow down all the way to the limit of the wire. Obviously a 36 core router will jitter way less processing packets then a consumer router. See test results and look at "router" and "25 ip rules". And the 64 byte packets. . https://mikrotik.com/product/CCR1036-8G-2SplusEM#fndtn-testresults

Its common for me to test routers, modem, switches for jitter. This image is typical for my testing and shows a typical Broadcom modem chip VS a Intel Chip. This testing is done at high temporal rates. This test is 10 times a second. The top graph is jitter.

VS.gif

View attachment 61759


How a modem, router or switch is effected as you pull packets thru is something I test all the time . each packet thru a device causes some effect on its CPU . T his effects any stream going thru the device. So each device is different. A examp le of this type of testing with modems is below. you can see the broadcom modem chip is unfazed by packet flow . T he intel chip is HIGHLY effected.


stress.gif
View attachment 61760

So I know modems/routers and switches inside out from real performance testing.

No one doing audio should be using "consumer" grade networking gear as jitter performance is really important.
 
Likes: matthias

matthias

Active Member
Mar 14, 2019
318
96
28
Germany
#5
Interesting what @romaz posted on the Taiko Extreme thread:

Recently, I upgraded my internet bandwidth from 200Mb/s to a full 1000Mb/s which forced me to upgrade to a different modem/router since this router maxed out at 300Mb/s of bandwidth. I purchased the following ARRIS SURFboard SBG8300 modem/router which is capable of a full gigabit of Internet bandwidth but it was with reluctance since my old modem/router had its clocks replaced and this one didn't:




My fears were unfounded because even without any clocks replaced, the SQ improvement with this modem/router is quite a bit better than the Netgear. Improved dynamics and a much bigger sound stage are what really stand out. Powered once again by my SR7, the improvement here is not so subtle.

This modem/router is also based on the Intel Puma chipset. But I trust @romaz that it sounds good.

What do you think about it?

Thanks

Matt
 

kswanson27

Active Member
Nov 22, 2018
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#7
Looks like the SB8200 is not compatible with bundled voice service which I have. Any other recommendations? I'm using Spectrum.
 
Apr 17, 2019
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#8
That correct.

What you want to do is get a telephony modem and a internet modem. Separate. This is a option for all cable companies. Its a rare option and usally you have to battle to get it.. So you provide whatever modem you want and they provide the telephony modem.

You dont want your modem with all the extra electronics in it for phone. More chips, dirty internal power supplies. You want a pure internet modem.

Your problem is a common one. It can be a battle tho.

Have your considered VoIP solutions ?
 

kswanson27

Active Member
Nov 22, 2018
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#9
Never heard of a telephony modem but I'll look into it. Is the SB8200 a "pure " internet modem?
 

matthias

Active Member
Mar 14, 2019
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#10
In Germany there are the Fritzbox modem/routers very popular.

They recently launched the Fritzbox 6660, it operates according DOCSIS 3.1 and the new WiFi 6 AX standard.

Do you know which chipset is inside?

Thanks

Matt
 

2ndLiner

Active Member
Dec 16, 2015
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#11
Thanks for your input on this, Xymox! I just spoke with my internet provider and I have a PACE 411N modem. It has a Broadcom chip and they do firmware updates every 12 to 18 months, if that. The other modem they offer is a PACE 5268AC but he felt this was beyond my need. Any thoughts on this? Thanks!
 

kswanson27

Active Member
Nov 22, 2018
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#12
How does a telephony modem install? Does it use the cable coax? How would an internet modem interface with it?
 
Apr 17, 2019
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#13
In Germany there are the Fritzbox modem/routers very popular.

They recently launched the Fritzbox 6660, it operates according DOCSIS 3.1 and the new WiFi 6 AX standard.

Do you know which chipset is inside?

Thanks

Matt
Ahhhh. Germany and fritzboxes.. Intel offered some kind of deals to ISP's and many worldwide went to the Puma chip. Intel had some kind of incentive that almost no one turned down. These were at the time exclusive deals to lock Broadcom out of that ISP. So the Puma spread far and wide rapidly before the horror of its performance was revealed. ISP's did eventually catch on and Intel is now trying to sell off its whole connected home division because of the mess.

The fritzboxes were puma plagued. They got updates but the performance in latency and jitter NEVER matched Broadcom.

I have not kept up on fritxboxes and if they are Broadcom based with this next rollout wave for 10G ( wifi 6 ) . I recommend some googling. The model number and puma.. People are keeping track because of the list of known issues.

I don't recommend going to 10G because these devices will include SDN, Software Defined Networking. This produces a higher level of jitter. You will never need 1Gbps, at least for a while, so going to OFDM modulation and DOCSIS 3.1 is good, the next step in this, Multi-Gig, brings a lot of issues and is more of a Trojan horse to allow SDN to allow ISPs to charge for different packages on the internet like they do for cable. Like the preimum package that includes youtube, facebook, etc.. That IS coming. At least in the US.

Watch out because this is from Cablelabs and they want you to drink the koolaid..
https://www.cablelabs.com/10g


Never heard of a telephony modem but I'll look into it. Is the SB8200 a "pure " internet modem?
Yes...

they offer is a PACE 5268AC but he felt this was beyond my need.
The pace looks like a DSL router. I do not have experence with DSL and jitter testing. I would guess DSL is a lot noisier and so has more retransmissions and stuff. So I think I would switch to a cable provider.

Also its important to seperate out Modem, router and wifi.

Seperating out these devices becomes FAR more complex when we talk about 10G as you now need to use at least 5Gbps ethernet connections, or 10Gbps. So you need a modem, router and wifi that support this. No normal human in a house even uses 1Gbps very often, if ever. So these multi-gig speeds are pure marketing talk to get people to buy into SDN 10G. LATENCY and JITTER is what matters, not bandwitdth.

Repeat after me... "Latency and Jitter matter, bandwidth does not".
 
Apr 17, 2019
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#14
How does a telephony modem install? Does it use the cable coax? How would an internet modem interface with it?
You use a coax splitter. One coax goes to the telephony modem and one goes to the internet modem..

OR you put the telephony modem elsewhere that you have a cable coax.
 

kswanson27

Active Member
Nov 22, 2018
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#15
My current modem is a Technicolor E31T2V1. Good modem or bad modem?
 

wil

Well-Known Member
Jul 22, 2015
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#16
I can prove its a TERRIBLE device..

https://www.theregister.co.uk/2017/08/09/intel_puma_modem_woes/

His SQ improvement was because he went to DOCSIS 3.1. Had he done the same thing with a SB8200, it would have been a much better result.

The issues with Intel Puma are WELL covered in the press.. The 8300 was a bad modem to start mods on.

https://www.google.com/search?sourc...hUKEwiRvbPk-NvnAhVCGDQIHSYqBHsQ4dUDCAc&uact=5
The 8300 is not on the "bad modems" list though.... I guess it should be?

What about the Arris BTG 710-200? It's the supplied Gateway for Att fiber and from everything I've been told there is no way to avoid use of the supplied Gateway. (The router in the Gateway unit can be bypassed however).
 

ketcham

Industry Expert
Feb 29, 2016
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#17
Ah! This EXPLAINS my findings. I made this upgrade to the Arris SB8200 and the improvement was profound. Equivalent to a multi thousand dollar component upgrade. I attributed this to a LPS added at the same time.

I was shocked. $600 upgrade (Router and Sbooster LPS). This became my number one recommended upgrade before an audio grade router and switch, which I sell. Both with excellent improvements but this one much, much cheaper and highly effective!

Thank you for this Thread!
 
Likes: Thuan

nenon

Active Member
Jan 29, 2020
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#18
@Xymox Excellent expert level analysis. I just went through all that in the past couple of months. And I can't agree more! But I wish you posted this 3 months ago. It would have saved me so much time :).
First, changing the all-in one box with just a cable modem is a big improvement. Then powering up with good LPS. Then modding the power section on the cable modem with better capacitors and DC cables - all the brought an improvement. A few more network tweaks and Qobuz is sounding better than ever. I also tested different cable modems. And guess which one I am using now? Arris SB8200.
I told this to a few other people and they all confirmed it was a great improvement.
 
Likes: Thuan
Apr 17, 2019
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#19
My current modem is a Technicolor E31T2V1. Good modem or bad modem?
Hehehe.. Come on,, you guys can google,,, hehehehe.. Just google the model number and the word Intel, or Puma, or broadcom.. Someone has looked into these things. For example https://www.google.com/search?ei=2s...hUKEwjnuNiG9tznAhWxLn0KHQhmAqcQ4dUDCAo&uact=5

The 8300 is not on the "bad modems" list though.... I guess it should be?
Yes it should be.. I will go edit the list. I don't maintain the list like I should.. Edit done, its now on the badmodems list.
I made this upgrade to the Arris SB8200 and the improvement was profound.
Good to hear that. It makes sense. DOCSIS 3.1 is a serious improvement in jitter and the Broadcom chip passes that goodness along.

HOWEVER.. There are a number of Broadcom based 3390 chip based modems, so, I can't say FOR SURE that a sb8200 is THE best for SQ. However, they *should* all sound about the same. If your handy with these things I recommend stuffing modems full of caps and using a linear supply.

I also tested different cable modems. And guess which one I am using now? Arris SB8200.
Interesting. I picked the 8200 because it was deployed by my cable company, Cox, and so would have good support. Not much room inside the case tho for caps. WHich Broadcom based device is best before mods for audio ? I am not sure.

Also the new wave of "multi-gig" modems hitting the streets now I have not tested yet. I suppose I need to get some and test them for jitter, latency and other things.
 
Apr 17, 2019
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#20
What about the Arris BTG 710-200? It's the supplied Gateway for Att fiber
As far as I know, fiber to the home is the very best in jitter and low latency. I do not have experence in testing these devices. I would guess its near ideal.
 

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