Pre amp confusion, which way should I go?

Mack errol

Active Member
Help please Guys & Girls….


Advice sort-

I’m ready for the next evolution of my humble family film room and I’m just not sure what is the best thing to do is as there’s so many different ways to go.

A bit about my room

4.089m long x 3.201m wide.
Central listening position is 1.375m off the rear wall and 2.320m from the face of the Center speaker.-

LCR Kef R500/R200C
Surround x4 Kef T301
Atmos x2 Kef CI 200QR
Sub x1 Kef Q400B
Receiver Denon x4300h

•Planning on fitting GIK acoustic panels x4 wall x1 ceiling to the first reflection points.( can’t be bothered to make them and I think their cost is reasonable.)

•Would love to install x2 more of the Kef CI 200QR taking me to 7.1.4.
But the advice might be to get a decent amp & sub before worrying about two more atmos?
If so what would you recommend.

•Looking to add an amplifier to the system rather than spending a fortune buying a 11.2 out of the box receiver. But I’m not sure how many channels I should power from the additional amp.

•Not sure on what cross over level I should set the different speakers at?

•I’ve always been told that Kef R500/200 are a tricky speaker to power well so I’ve probably never heard them sounding their best.

•On the Denon listening levels are 47.5 to 57.5 depending if my daughter is in the room or what the source is like. 100% films no music.

• Set up with Denons Audyssey but I always tweak the surrounds and atmos’ up.

I’ve attached a sketch of the room.

@Mr Wolf @Dobbyisfree

Any help or advice would be greatly appreciated.

👍🏽 Mack.

image.jpg
 

Mr Wolf

Well-known Member
Mack, the good news is that your maximum 57 listening level is about 23.5dB below reference level which is not really that loud and well within the capabilities of your AVR. Your least sensitive front speakers are 87dB sensitivity. According to my maths your X4300 AVR should easily be able to power your system to about 10dB below reference level and still have 3dB of headroom which means at your listening level you have about 16dB of headroom which is huge. In short, you don’t need a power amp.

If you were to add a power amp to enable a 7.1.4 set-up I would put it on the front speakers as they have to cover the loudest peaks and are furthest from you. In your sized room though, 7.1.2 is probably a better configuration due to the close proximity of the back channels to the rear heights.
 
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rccarguy2

Well-known Member
That's a small room Tbh I'd rather have fewer higher quality speakers than more lower quality speakers crammed in.
 

Dobbyisfree

Well-known Member
I think that, in the UK, a 4 by 3 metre room is not at all a "small room" to normal people. In fact, I would call it a good sized room. Millions of people in this country have worked very hard for a living for decades and don't have a reception room that big in their property (if they're lucky enough to own/mortgage a property). :) And I also this that KEF R series are considered pretty high quality speakers? Are you feeling ok rccarguy2?

@Mr Wolf there is a lot of content about low impedance troughs on the KEF R range of speakers, which I believe Mackeral is referring to.

Also, I'm extremely surprised you didn't mention the one sealed 12" sub in that room. Not sure if, even at 23dB, it would do the business. @Mack errol what reference level offset do you have dynamic EQ on, or do you have it switched off?
 

Mr Wolf

Well-known Member
@Mr Wolf there is a lot of content about low impedance troughs on the KEF R range of speakers, which I believe Mackeral is referring to.
Low impedance dips are an issue if an amp becomes current limited. At those volume levels there is no way that the AVR will be current limited at all. As the difference between power output for a fixed amount of current going into 8-Ohm and 4-Ohm loads is double (i.e. 3dB), only 3dB of extra SPL headroom is required to be able to handle any potential impedance dips.

Also, I'm extremely surprised you didn't mention the one sealed 12" sub in that room.
Hey, I was going easy on him! :) Seriously, at those low listening levels in circa 1,100Ft3 room that single sub may even be enough SPL-wise although I like to see at least two subs to smooth out the response.
 

Mr Wolf

Well-known Member
I just noticed Mack also asked about recommended speaker crossover settings.

Personally I would set everything at 80Hz apart from the channels using the T301s which I would set at 90hz (or maybe even 100Hz) due to their F3 point only being 80Hz.
 

Dobbyisfree

Well-known Member
apart from the channels using the T301s which I would set at 90hz (or maybe even 100Hz) due to their F3 point only being 80Hz.

I'd be surprised if they could be set that low. @Mack errol please share the Audyssey app results for the surrounds and surround backs and we can give a good opinion on the best crossover. Screenshot is fine - but *.ady file better if you know how to make a copy of this on your phone/tablet.
 

Mack errol

Active Member
Thank you very much for the replies and information shared! Has given me a lot to think about at work today.

So in short what I class as plenty loud enough is 23.5db below reference level. Do folk listen at this reference level? If every 3db the sound is doubled that would surely be ear bleeding levels or am I missing something?

My wife will be happy that the recommendation is that a power amp isn’t necessary (did she message you in advance? 🤣).

We did an extension that was completed Summer 2019, where I was very lucky to be able to plan a film room, I would have liked to have been able to go bigger but due to boundaries that was the max I could go to.
I did partition the front wall out so there is a void behind the front speakers that is accessible from another room as one day I would like to do a Ci on the LRC.

if I get a chance this evening I will sort out the information/screenshots of the audyssey setup.

@Mr Wolf You’re not the only person to say stick at 2 on the ceiling speakers, with this in mind maybe I get the acoustic panels done then look at getting a decent sub or two.
Any recommendations on the sub?

thank you again Mr Wolf for your time spent doing the calculations.

👍🏽 Mack.
 

Mack errol

Active Member
@Dobbyisfree

unfortunately I don’t know how to make .ady file so I apologise in advance for the screen shots.

This is currently what it is all set up at using Audyssey plus then a few tweaks from me ie playing around with cross overs and dynamic EQ etc.

i’d be more than happy to run Audyssey again.

cheers,

Mack.
 

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Mr Wolf

Well-known Member
Do folk listen at this reference level? If every 3db the sound is doubled that would surely be ear bleeding levels or am I missing something?
Based on what I’ve seen online, if their systems are calibrated, I suspect most people will be listening to reference sources in the -15db to -20dB range so you’re not much below this.

Perceived loudness is doubled for every 10dB increase (not 3dB) and this requires 10x the amplifier power. The maximum 20dB transient peaks found in movies therefore require 100x the amplifier power than that of the average soundtrack level.

Doubling amplifier power yields a 3dB increase which is about a 23% increase in perceived loudness.

I favour ported subs for movies but not eveybody does. Have a look at the SVS PB-1000 Pro model.
 

Jester1066

Well-known Member
@Dobbyisfree

unfortunately I don’t know how to make .ady file so I apologise in advance for the screen shots.

This is currently what it is all set up at using Audyssey plus then a few tweaks from me ie playing around with cross overs and dynamic EQ etc.

i’d be more than happy to run Audyssey again.

cheers,

Mack.
Hi

A few things I noticed from those screenshots.

Front crossover is set to Full Band: I'd change this to 80Hz - This will meab more of the low frequencies will be handled/directed to the subwoofer, which is precisely what it designed to do.*

*If you're unable to set to the crossover for your front speakers to 80Hz, check to see if their size is set as "large". If so, change this to "small". You should then be able to set the front crossover to 80Hz

I'd also change the LPF from 100Hz to 120Hz.

😊
 

Gasp3621

Distinguished Member
Hey, I was going easy on him! :) Seriously, at those low listening levels in circa 1,100Ft3 room that single sub may even be enough SPL-wise although I like to see at least two subs to smooth out the response.

That is actually 10" sealed sub with 28hz +/- 3db spec, but in close-miked response of Sound and Vision found 39hz -3db and -6db 35hz. Typical small 5.1 package sub to keep nagging wifes happy.

However i´m more worried how the subwoofer is placed as the response atm looks horrible. With the MLP at middle 1,37m from rear wall the front wall is best location for the subwoofer, but even that shows big suck out 45 - 75hz range so the couch need to be moved closer to rear wall!

@Mack errol if you can then move your couch about 1meter or less from the rear wall and place your subwoofer on front wall next to your front mains about 25% front wall width either side. Your subwoofer should sound lot better after re-doing Audussey setup and boosting the subwoofer level by ~3db depending of taste. To be able to do this you would set the sub at roughly 78db at on-screen with Audussey, it can go little over the green level to red don´t worry about the warning just set it higher than the usual 75db. As long as the subwoofer level comes back under -12db you are fine as you have more headroom to tweak it. Audussey is known to set the woofers to anemic level.

Here is the response with the sub behind the couch. I think the room simulation has been quite precise showing bigger nulls in square room without odd shapes/openings. It`s safe to assume the sub is not in proper position atm.

room response.png



And here is the response with listener 0,50meter from rear wall with the sub at front wall 1/4.

room response 2.png
 

Jase

Distinguished Member
@Dobbyisfree

unfortunately I don’t know how to make .ady file so I apologise in advance for the screen shots.

This is currently what it is all set up at using Audyssey plus then a few tweaks from me ie playing around with cross overs and dynamic EQ etc.

i’d be more than happy to run Audyssey again.

cheers,

Mack.

I'd turn off Loudness Management as that is compressing the dynamic range of Dolby sources.

The other thing to watch out for is the Dialog Level Adjustment (and Subwoofer Level Adjustment). On the older Denon and Marantz models they promptly ignore any setting in the Levels menu when turned on and are effectively start at 0db. By increasing that to +4db you've actually set the Centre Channel 10db higher.

I'd turn it off and use the main Channel Level settings in the Manual Setup menu where it's applied globally to all modes. Alternatively use the Options button and adjust it just for the current Input/Mode.

The latest Denon and Marantz models fixed this 'bug' so they work as intended.
 

Mack errol

Active Member
Based on what I’ve seen online, if their systems are calibrated, I suspect most people will be listening to reference sources in the -15db to -20dB range so you’re not much below this.

Perceived loudness is doubled for every 10dB increase (not 3dB) and this requires 10x the amplifier power. The maximum 20dB transient peaks found in movies therefore require 100x the amplifier power than that of the average soundtrack level.

Doubling amplifier power yields a 3dB increase which is about a 23% increase in perceived loudness.

I favour ported subs for movies but not eveybody does. Have a look at the SVS PB-1000 Pro model.
Thank you for explaining that and I’ll shall be researching into a new sub if it isn’t a necessity to jump .4 atmos and ram an amp in.
 

Mack errol

Active Member
Hi

A few things I noticed from those screenshots.

Front crossover is set to Full Band: I'd change this to 80Hz - This will meab more of the low frequencies will be handled/directed to the subwoofer, which is precisely what it designed to do.*

*If you're unable to set to the crossover for your front speakers to 80Hz, check to see if their size is set as "large". If so, change this to "small". You should then be able to set the front crossover to 80Hz

I'd also change the LPF from 100Hz to 120Hz.

😊
Thank you Jester, if I get a chance this evening I might annoy the wife by re doing the Audyssey and will try those tweaks.
 

Mack errol

Active Member
That is actually 10" sealed sub with 28hz +/- 3db spec, but in close-miked response of Sound and Vision found 39hz -3db and -6db 35hz. Typical small 5.1 package sub to keep nagging wifes happy.

However i´m more worried how the subwoofer is placed as the response atm looks horrible. With the MLP at middle 1,37m from rear wall the front wall is best location for the subwoofer, but even that shows big suck out 45 - 75hz range so the couch need to be moved closer to rear wall!

@Mack errol if you can then move your couch about 1meter or less from the rear wall and place your subwoofer on front wall next to your front mains about 25% front wall width either side. Your subwoofer should sound lot better after re-doing Audussey setup and boosting the subwoofer level by ~3db depending of taste. To be able to do this you would set the sub at roughly 78db at on-screen with Audussey, it can go little over the green level to red don´t worry about the warning just set it higher than the usual 75db. As long as the subwoofer level comes back under -12db you are fine as you have more headroom to tweak it. Audussey is known to set the woofers to anemic level.

Here is the response with the sub behind the couch. I think the room simulation has been quite precise showing bigger nulls in square room without odd shapes/openings. It`s safe to assume the sub is not in proper position atm.

View attachment 1570699


And here is the response with listener 0,50meter from rear wall with the sub at front wall 1/4.

View attachment 1570700
Hello Gasp,

Thank you for taking the time to run the room simulation. I don’t really want to move the sofa back as I’ve used this position to set the position for the surrounds etc and also there’s no room near the fronts due to the unit my screen is on. My room has been a slow evolution , the Q400b sub was part of my Kef Q series speakers before I upgraded them, I suppose I’ve never really taken subs that seriously as being overly important, just in denial knowing I’m wrong.

Could I put the sub under a table or as a small coffee table and have it in front of the MLP? 🤣🤣 I’m joking but also mean it.

I am going to tweak with the sub tho when I re do Audyssey hopefully tonight.

At some point I’d like to upgrade from my 65” Oled to something bigger but mount it on the wall, which would then allow me to totally downsize the unit for the center speaker/receiver/4k player giving me the new location for a sub or two.
 

Gasp3621

Distinguished Member
Hello Gasp,

Thank you for taking the time to run the room simulation. I don’t really want to move the sofa back as I’ve used this position to set the position for the surrounds etc and also there’s no room near the fronts due to the unit my screen is on. My room has been a slow evolution , the Q400b sub was part of my Kef Q series speakers before I upgraded them, I suppose I’ve never really taken subs that seriously as being overly important, just in denial knowing I’m wrong.

Could I put the sub under a table or as a small coffee table and have it in front of the MLP? 🤣🤣 I’m joking but also mean it.

I am going to tweak with the sub tho when I re do Audyssey hopefully tonight.

At some point I’d like to upgrade from my 65” Oled to something bigger but mount it on the wall, which would then allow me to totally downsize the unit for the center speaker/receiver/4k player giving me the new location for a sub or two.

There is no good spot for the sub in your room if you sit in that spot you told as i put that dimension in the program. The response gets lot better if you move the couch little bit closer to rear wall. If you going to move the sub can you place it at front wall? Corners or between your main speakers?
 

Mack errol

Active Member
There is no good spot for the sub in your room if you sit in that spot you told as i put that dimension in the program. The response gets lot better if you move the couch little bit closer to rear wall. If you going to move the sub can you place it at front wall? Corners or between your main speakers?
No, unfortunately not as I said above there is no room due to the size of the tv unit.
Eventually when the screen goes on the wall
I will be able to get the sub(s) on the front wall in between the front speakers and the smaller unit.
 

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Gasp3621

Distinguished Member
No, unfortunately not as I said above there is no room due to the size of the tv unit.
Eventually when the screen goes on the wall
I will be able to get the sub(s) on the front wall in between the front speakers and the smaller unit.
Ah sorry i missed that part. The response gets better at the front, but still not good and it would be really shame if you buy new sub or two and can`t move the couch. Usually REW rom sim has been accurate regarding the nulls as you don`t have openings/odd shapes. You are losing quite a bit impact in the 45-75hz region which you will get back if the MLP is moved closer to rear wall, but yeah it´s then up to you will you make the changes later for the new MLP. Otherwise the new subs will go bit waste. At least with the information we have now. You can buy Umik-1 (100£) and measure the response to be sure, but prepare for changes still.

If you move the sub directly behind your seat so it would be closest to listener it will give you more impact and shook the couch more which you will love or hate after month, haha. The idea with nearfield placement is the direct energy from sub reaches you before it interacts with room. When i mean nearfield it means the driver is few cm out from the back of couch so very close! Then run Audussey and check the subwoofer level which you now have at -6,5db which is ideal by the way, lowering this figure you will get more "oomph". Typically people lower it 3-6db with Audussey depending of their taste. But of course try first without tweaking as you will feel it now bit more. Ideally play some bluray movie which has hard hitting bass, some blockbuster flick.
 

Mack errol

Active Member
Ah sorry i missed that part. The response gets better at the front, but still not good and it would be really shame if you buy new sub or two and can`t move the couch. Usually REW rom sim has been accurate regarding the nulls as you don`t have openings/odd shapes. You are losing quite a bit impact in the 45-75hz region which you will get back if the MLP is moved closer to rear wall, but yeah it´s then up to you will you make the changes later for the new MLP. Otherwise the new subs will go bit waste. At least with the information we have now. You can buy Umik-1 (100£) and measure the response to be sure, but prepare for changes still.

If you move the sub directly behind your seat so it would be closest to listener it will give you more impact and shook the couch more which you will love or hate after month, haha. The idea with nearfield placement is the direct energy from sub reaches you before it interacts with room. When i mean nearfield it means the driver is few cm out from the back of couch so very close! Then run Audussey and check the subwoofer level which you now have at -6,5db which is ideal by the way, lowering this figure you will get more "oomph". Typically people lower it 3-6db with Audussey depending of their taste. But of course try first without tweaking as you will feel it now bit more. Ideally play some bluray movie which has hard hitting bass, some blockbuster flick.
No problem, I won’t get a new sub(s) until the screen is on the wall, slow and steady evolution of my room so it will take a while.
I’d already done the Audyssey by the time I’d seen your message so the sub hasn’t moved, I’ll defo try it right behind me as that does sound like a good potential temporary position.
Thank you for your time and advice.
 

Mack errol

Active Member
I’ve attached tonight’s results from Audyssey and followed the advice. If anyone has any further recommendations from my setting please do let me know.

Only had time to put my go to disc of Blade Runner 2049 on and watch a few scenes and to be honest it’s probably the best it has sound, usually I’m tweaking up the surrounds a couple of db but didn’t need to and the rain (there’s a lot of rain In this film) felt more enveloping and substantial.
Thank you everyone so far that has chipped in on this thread!

The last photo is just showing where I’ve adjusted up the center 4db rather than having dialogue adjust on.
 

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Gasp3621

Distinguished Member
Looks fine to me. You could however change the Reference to Flat and listen which you prefer more. :) Reference does high frequency roll-off, Flat doesn´t. If you like bit more treble give it a go! Probably best to test some familiar chapter of movie which has lot of high freq stuff or just leave it on for couple weeks..
 

Jase

Distinguished Member
I’ve attached tonight’s results from Audyssey and followed the advice. If anyone has any further recommendations from my setting please do let me know.

Only had time to put my go to disc of Blade Runner 2049 on and watch a few scenes and to be honest it’s probably the best it has sound, usually I’m tweaking up the surrounds a couple of db but didn’t need to and the rain (there’s a lot of rain In this film) felt more enveloping and substantial.
Thank you everyone so far that has chipped in on this thread!

The last photo is just showing where I’ve adjusted up the center 4db rather than having dialogue adjust on.

Ideally turn the Dialog Level Adjust to Off as it's still overriding your settings. Not as much as before but it's still 1.5db higher. If you like it at that level turn it off and set it in the main speaker levels to 0db. You'll then know exactly where you are in relation to the levels set when you ran Audyssey.
 

Mack errol

Active Member
@Mr Wolf @Dobbyisfree @Jase @Gasp3621 @Jester1066

I started this thread thinking I needed more power and speakers. With the advice and time you guys have given me on here my system is sounding the best it ever has. It really sounds like a blanket has been taken off my speakers and they all have more presence.
Normally as soon as Audyssey is run I start tweaking (the wrong things).

Mr Wolf you get a special mention as my wife is happy that I’ve stopped talking about Pre amps and more speakers. 😂

Thank you all so much!!
👍🏽
 

rccarguy2

Well-known Member
I would still borrow a good three channel amp for front and center you won't nee the power however find good amps drive lower impedance speakers better those kef r aren't easiest of speakers to drive
 

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