Question on the Denon S660h for hifi 2.0 useage with Aria 948

[Shannow85]

Hello everybody,

Very new to this forum but I've been looking at the great reviews/tests for a while.

I have recently bought a pair of Focal Aria 948 and having spent my budget at the time and having no integrated I basically bought the cheapest AVR I could get hold of with a reliable brand = the Denon S660H.
The Aria are great and I'm very pleased with them (waited 9 years before having a good deal and the money) but I wanted to be sure that the Denon wasn't holding back the speakers in the chain.

Anyway I started measuring the S660H with a voltmeter/ampmeter to make several graphs albeit primitive compared with what you do here (all in direct mode no eq or anything weird).

Damping factor not being quoted for this amp I calculated a 0.9ohms internal resistance @1khz 8ohms resistive load ... the Aria can drop to 2.6ohms which gives me a 3 damping factor at it's lowest. Read a lot of papers online about damping, it's not that important apparently but still I imagine that it can be a factor if other stuff is wonky. I discovered that voltage is not constant on the AVR. Pretty steady from 200-20000khz but increases quite a lot from 100hz down to 20hz (30% or so) . Can't explain that.

Tonight after making another test, with a 4ohms load this time, I realized that my measurements are not repeatable. Everything is set the same. The signal input doesn't change the amp is always in direct mode but no matter what if i go back and forth or on/off with a signal or even touch the load and then remove it on the fly it changes the voltage to something rather random (within 20-30%) .
I decided to hook up an old oscilloscope and it shows the same randomness in amplitude. The signal is a clean wave but becomes blurry(micro fuzzy) below 100hz and becomes unstable at 5khz+ (overall amplitude of the voltage increase/decrease on a slow cycle).

Could someone tell me if there's some logic here ? The amp is not great ? A bad match with the Aria ? My measurements/knowledge is garbage ?

Thank you a lot in advance. Sorry if I'm unclear as my English is not my maternal language.

 

[Palmspar]

The aria 948 is a very sensitive speaker only if you listen very loud above 100db or so maybe something wil go wrong, the tweeter burns out or the amp goes in protection.
In a normal room a 50watt@8 ohm 2 channel amp can drive almost every speaker without problems.
I think the voltage increase is that the amp has more power to drive the low 20-100hz signals.
Withoud higher voltage the amp must send way more amperes to the speakers for the same watts and i think it can handele that, so its designd mayby.

 

[Chazz6]

If you are happy with the sound, the measurements are not a principal question.

You can try simple experiments. For example, hook up the speakers from terminal pair 1, then 2, ... 5.

 

[Shannow85]

Thanks for the replies. I don't listen to music loudly, i've never measured it but it's probably never beyond 90-95db.
The speakers seems to be lacking a little punch compared with the shop's demo. There's a massive drop between 50-70hz and a big bump at 100hz although it's almost certainly due to the room (can't move around the speakers much more than 50cm there and there and the room is very asymmetrical) I wanted to be sure it wasn't the amp doing funny things as this error does follow the impedance curve of the speakers (conveniently/coincidence).

 

[VintageFlanker]

I wanted to be sure that the Denon wasn't holding back the speakers in the chain.

It is indeed.

The S660H is nowhere near an amp suitable for Aria 948s, I regret. In whatever (large enough) room these towers would be relevant to put in. Unless you don't plan to listen above ≈80dB or so, then I see no point for such floorstanders.

 

[delta76]

It is indeed.

The S660H is nowhere near an amp suitable for Aria 948s, I regret. In whatever (large enough) room these towers would be relevant to put. Unless you don't plan to listen above ≈80dB or so, then I see no point for such floorstanders.

they certainly can handle 10w load which drive 948 to around 94-95dB, so loud enough in a fairly large room.
I don't listen very loud either, but once in a while it feels good to have the apartment filled with music

 

[Shannow85]

Thank you again for the replies.

I have tested again this time in correlation with REW and the oscilloscope . Here's what I found compared with the same speakers tested in a review with a Naim amp :

So a little difference that changes the SPL by 3db at places.

Also with REW I discovered that any mode movie/music/game in stereo puts a 3db increase under 100hz and over 5khz automatically, nothing you can do about it.
Direct mode of course removes EQ. In phono movie/music/game mode doesn't alter the frequency range compared with direct mode. Probably because these mode use the DAC and the DAC is out when using phone I guess.
The problem is that it means I can't use EQ because EQ is in anymode other than Direct and the music/movie/game mode changes too much the sound by itself and can't be applied to phono ...
More simply put:
-Phono = EQ or Direct
-Movie/music/game mode = EQ+booted low/high or direct

Only way to get everythingon the same sound shape is in direct mode.

Anyway tinkering about other amps (winter sales at the moment here in France). If I were to try another amp it has to have Phono MM for my SL1200mk2, and bluetooth. Ideally I'd like HDMI ARC for convenience (wife will moan at yet another remote)...

Here's the candidates :
- Marrantz Stereo 70s : I'm afraid it's a more expensive stripped down version of the Cinema 70s. It was reviewed here and doesn't have a great score.
- Advance Paris A7 Playstream : It's french and obscure as there is no review with measurements but it certainly looks fancy on paper and there's quite some discount on it at the moment. DAC is PCM 1796. THD is 0.004% at 24w (why 24? it's rated at 115w on 8ohms) it's a class AB .
-Yamaha RN1000A : Quite over budget but if it's great I can wait a few months of even a year to either build up budget or wait for a good sale/second hand.

Do you have a recommendation ?

Thank you in advance

Jonathan

 

[Shannow85]

Ok I have resolved the voltage curve issue.
It was on the phone the Atmos Dolby that was enabled.
And on youtube app it was the automatic volume level.

Only issue I'm trying to solve now is the weird distortion I'm hearing on vocals. Whatever the source (vinyl record, phone , tv ) there's this weird wobbly/watery type sound on female vocals (high pitched ) and cymbals.
Could be a coincidence but even with a constant max voltage across the frequency at around 4-5khz there's a wobble like a heartbeat. It accelerates quite alot up to 12khz-14khz (sine wave increasing/decreasing by as much as 50% at fast heartbeat rate). Sometimes it's there sometimes it's not. When it's not there sending a sine wave signal for more than 40-60s starts the motion again.

 

[Overseas]

Wiim Amp should do it for your room, also has HDMI ARC, streaming and PEQ. Try it from Audiophonics.

 

[Shannow85]

Thanks for the amp suggestion. I've done a few REW graphs that I can post and I can see that what is bothering me is a second harmonic distortion that starts around 4khz and skyrockets to 10khz at 17% distortion. Don't know where this is coming from. The room ? I have this no matter where i mic. Left and right speaker are not in the same reflection environment at all yet I have the same thd. The amp ? It's so awfull I doubt it. Any idea ?

 

[HarmonicTHD]

Thanks for the amp suggestion. I've done a few REW graphs that I can post and I can see that what is bothering me is a second harmonic distortion that starts around 4khz and skyrockets to 10khz at 17% distortion. Don't know where this is coming from. The room ? I have this no matter where i mic. Left and right speaker are not in the same reflection environment at all yet I have the same thd. The amp ? It's so awfull I doubt it. Any idea ?

Either the room (my guess) or your test setup. The exclude the latter, can you describe it and ideally post pics and REW graphs.

THD is not really reliably measured for speakers in a room. Even the Klippel struggles and Amir kept the measurements out at the beginning afair

 

[Shannow85]

Here's the Aria 948 at 4 m distance stereo :

The aria right side 948 mic straight at the tweeter 10inch :

The aria left side 948 mic straight at the tweeter 10inch :


For mic comparision the BT1700 edifier (active speakers ) at 1m :

And A headphone DT700Prox closed on mic :

star share server gratuit

 

[Shannow85]

Red is second order harmonics. On the headphones and the BT1700 active speakers the distortion doesn't go beyond floor noise (dark brown) or barely.
The Aria 948 always show 20% or so distortion at 10khz whether close vs far vs left vs right . The room topology of the left and right speaker position is very asymmetrical.

 

[Shannow85]

Ok I just had a dreadful though. Started finding thread on blown tweeters on focal Aria and I bought mine ex demo in store....
Luckily I just bought a brand new central speaker cc900 (same tweeter) and tested it. In the panic moment i literally just plugged the thing on the right hand channel in situe, on the floor next to the 948 (in the hallway) but 90 degrees :


Brand new tweeter in a different situation (reflection wise) same 2nd harmonic distortion ... so it's not the speaker and I think we can eliminate room reflection.

edit: The surprising bass extension is almost certainly the left channel aria 948 plugged in that is picked up in the background.

 

[Shannow85]

Ok problem partially solved, after plenty of tests.
Here's the Tuner input as I didn't have CD input on the s660h but it should still be analogue :

No more 2nd order big distortion (it top arounds 1%)
And for double checking here is the same speaker, same distance absolutely nothing has changed in position/setup except now through Bluetooth :

the 2nd order harmonics is there again so I'd guess this is the DAC error.
Can't test phono but I'm wondering if the preamp part of the phono is separate or does the DAC deals with it as well ?

Edit: Ok further tests. It's anything but pure/direct mode gives me this harmonic. In other words do not use any sound mode or eq on this amp with Bluetooth at least. When in tuner mode I tried all modes and did not have this distortion.

 

[Shannow85]

Do you think it would be silly to have two amps ? Meaning one for AV and one for my TT CD player etc ? I'll have a switcher to wire amp A or amp B to the Speakers. There's a pretty good deal on a Second hand As 2100 not so far and I do wonder if it's viable...
I do understand that there likely won't be an audible upgrade but it's a nicer machine to handle, the eq will be useable and used (quite different than my AVR) and of course who doesn't love vumeters ....

 

[Shannow85]

Oh well the as2100 has gone so this took care of the decision...
There's still an as1100 for not too bad price in my area. It would be used primarily for the turntable mm/mc phono and although the Yamaha phono is probably better than my denon avr I doubt that the difference will be audible. Is it worth it ?