impedence

[JohnnieB]

I can't seem to find the thread that was recently posted on here, concerning impedence between the pre/pro and amp. The reason I'm looking is, I don't seem to have a wide usable volume range from my pre. I have to get up to half volume to be at what I would consider a soft volume. From there it ramps pretty quickly to 80. It just seems as though all my adjustment is in the 50-80 range. This is by the display on my pre.
My amp is the Emo XPA-2. Input impedence is 23.5 kohms unbalanced, 33 kohms balanced. I can't find a spec on the Sherbourn PT-7030 pre.
Could a large mismatch in the impedence be causing what I tried to describe?

 

[Speedskater]

While this is not a help.
It's not an impedance problem. The Sherbourn is a modern component and should have an output impedance of under 200 Ohms. So a input impedance over 10 k Ohms is a typical load.
When it ramps pretty quickly to 80 - how loud is it?

Do you mean that it lacks resolution in small volume changes or that it never gets really loud?

 

[JohnnieB]

It gets loud. 80 is as far as I push it, that's loud enough to make you want to turn it down after a minute or so. 40 is whisper quiet. So I go from whisper to DAMN in .6 seconds. The usable range on the pre, according to the display as I see it, is 40-80. It seems in that range it's hard to find the right volume. It's either a little too soft or a little too loud, never seems to be just right. Make any sense?

 

[JohnnieB]

Maybe it's all a non-issue. I need to worry less about the volume display and more about what level is good to my ear. Maybe I'm just looking for a reason to get a different pre/pro.

 

[PENG]

Maybe it's all a non-issue. I need to worry less about the volume display and more about what level is good to my ear. Maybe I'm just looking for a reason to get a different pre/pro.

It's just the way they choose to display, sounds normal to me.

 

[agarwalro]

The two schemes used are:

Absolute: 0 - 100 (0 = Mute, 100 = Max gain in pre-amp stage. This is useless since loudness or measured SPL for 23 or 81 in one person's setup could be very different from someone else. In fact, unless room/ setup/ listening position are nearly identical the same absolute reading is going to have different loudness for everyone. By effect, if you wanted to hear at the levels the recording engineer intended, there is no reference.

Relative: -x dB to +x dB (-x dB below Reference Level, +x dB above. Reference Level is 0dB. After any system is calibrated, y dB on that system will be equal in loudness to y dB measured in every other calibrated system. Now one can say, if I am listening at -5 dB, that is 5 dB below what he recording engineer meant for Reference Level. Further, if someone says, I usually listen a -50 dB we know that is pretty damn soft or if someone says, I was playing at +10 dB and my amp blew the woofer, well, we know that was pretty dang loud. Reference Level is very fixed for THX, DD and DTS, but no standard exists for CD/SACD recordings.)

From this AVS thread,

Reference is defined as -20dBFS or 85dB for calibration purposes. 75dB is used with THX calibration materials. THX test tracks were designed for 75dB since 85dB was considered too loud and potentially harmful (short term and long term hearing loss). 105dB SPL is -0dBFS except for subwoofers which are 10dB higher. Because our sensitivity to various frequencies varies with loudness (or SPL), it is important to calibrate to the defined reference standard. 105dB, BTW, is not "reference" but rather defines the upper minimum limit of dynamic range.

Real men use the relative scale . That's all I really came to say LOL!

 

[slipperybidness]

If you can adjust the volume to appropriate levels, then there is no problem. Don't even worry about the #s on the display.

 

[JohnnieB]

Probably just as well. Thanks everyone. Guess I wont be getting a different pre, at least not for a while.

 

[JohnnieB]

After contemplating my situation, I have narrowed it down to this. I lose dynamics at lower volumes. Some may say DUH, of course you are. My last system could play with great dynamics at lower volumes. It would fill the room with rich flowing sound at relatively low volumes. Of course this is an entirely different beast and will behave differently, but what is probably the biggest contributor.

Speaker impedence.
Driver size.
Amp pre both.
Room response.

Are any or all of these factors.

 

[RichB]

^^^
What are your speakers and room size?

- Rich

 

[JohnnieB]

Room is 12x22x8. This is both the L.R. and dining area. I have the speakers set up on one half of the long wall due to placement constraints. I am running Ascend Sierra towers RAAL off of an Emo XPA-2.

 

[agarwalro]

but what is probably the biggest contributor.

Speaker impedence.
Driver size.
Amp pre both.
Room response.

It seems like room response may be the culprit. Does your current pre-pro have room response correction?

Room is 12x22x8. This is both the L.R. and dining area. I have the speakers set up on one half of the long wall due to placement constraints. I am running Ascend Sierra towers RAAL off of an Emo XPA-2.

That combination of speakers and amp should not leave you wanting more. (My Sierra 2 don't and are supposed to be inferior to the towers for midrange and treble dynamics.)

Is the setup not symmetric? Meaning L and R set up as mirror image?

IMO, if you haven't already, look into measuring techniques to understand what is going on.

What did you have before? Sorry for making you restate this.

 

[JohnnieB]

Agarwalro, you'll have to let me know what that means , My Sherbourn does not have room correction. That's one of the reasons I liked this pre/pro. Also one of the features I wish it had. I know. I'm only dealing with my L/R mains right now.

The system is as symmetric as I can get it with a tape measure and a couple hours of listening, tweeking, listening, tweek...you get the picture. I have been looking at meters and mics, measuring systems and software. I haven't bought them yet due to lack of funds and trying to save for a sub. May not be everyones priority, but I NEED a sub.

My last system was a pair of Cerwin Vega AT80s powered by a Kenwood 400w amp and matching pre. Don't remember the model, think 1990. I could play these loud or soft, always had great dynamics. I've heard people describe it before, and I know what they are talking about. That smooth sweet flow that floats through the house at a little less than normal talking volume. At a guess 55db. As I posted earlier, I have to get up to 62, 65 on my pre to get that dynamic sound, but it is just a little louder than I want it to be for background listening.

I did construct a couple of 24x36" cloth covered poly filled wall hangings, put them on the wall either side of a 16x16" window that is directly behind my sofa. The sofa is right against the wall. Given the speaker placement, I sit about 9.5 ft from the speakers. I think it helped with an upper mid reflection, sort of an echo from the wall directly behind the sofa. Might be wishful thinking.

That's about as well as I can describe it. If it makes any sense that would make me feel better. By the way, Thanks all around for everyone who has replied to this. Hopefully I'm not wasting everyones time, looking for the proverbial white whale.

 

[agarwalro]

You can easily add a stand alone room response shaping tool. Look up MiniDSP, Behringer DCX2496, FBQ1000, DEQx, etc. The first step though is room assessment. For this you should learn about Room EQ Wizard. HTS has a forum section dedicated to REW. REW is nice since the cost of entry is lowest. Software is free to download at HTS, add a USB Mic and you are off. I suppose lowest cost of entry would be just a SPL meter, test tone CD and graph paper. But, the sheer ease of use (after the learning curve tapers off) and the wealth of knowledge provided by REW makes up for the $25-50 extra.

I have no idea what the CV AT80 sound like. I am nonplussed as to why the Sierra Towers + Emo XPA-2 lack dynamics for you. I would hope it would at least equal the CV from 25 years ago.

The listening position is definitely sub optimal. Being up against the wall, room gain is high and it could contribute to lack of midrange clarity. It still does not explain the lack of 'smooth sweet flow that floats through the house'. Nice picturesque language there. You could be missing a career reviewing high end audio gear published without measurements . It could be that you have become so accustomed to the inaccuracy of the CV that these just don't sound as appealing. Like the situation where folks accustomed to high distortion boomy bass when presented with accurate yet equally loud bass tend to feel like there is not the same "effect". It could be that your memory is making things more vivid than they were (it does sound like you were high on something when listening to the CV LOLOL! ). It could be that the speakers/pre-pro/amp have a defect. Thought, the last one is least likely.

'Agarwalro' is what happens when lack of creativity overlaps with signing up for AH. Not that I'd consider myself a creative type to begin with... Agarwal is my last name and ro is short for Rohit, my first name.

 

[PENG]

My last system was a pair of Cerwin Vega AT80s powered by a Kenwood 400w amp and matching pre.

I don't know the specs of those speakers but I can see why they would sound more dynamic to you at low listening volume because:

- Knowing Cerwin Vega speakers in general, they are likely much more sensitive than the Ascend towers.

- They also likely to have higher nominal impedance.

- They probably exaggerate the mid bass and mid treble.

- The Ascends are designed to sound neutral and accurate, that means you will hear less bass and treble at lower volume and may perceive that as lack of dynamics.

I am just guessing but I bet I won't be far off that all of the above are true at least to a point. That means the Cerwin Vega speakers in your previous system would in fact likely sound more dynamic than your present system.

I think you will enjoy a Denon or Marantz AVR that comes with Audyssey DEQ. Something like a Denon X-4000, Marantz SR-6008, or even a Denon AVR-3312, 3313 will do if you can find any of them at blow out prices. You can always sell your Shelbourne to help finance a new AVR.

 

[ski2xblack]

After contemplating my situation, I have narrowed it down to this. I lose dynamics at lower volumes. Some may say DUH, of course you are. My last system could play with great dynamics at lower volumes. It would fill the room with rich flowing sound at relatively low volumes. Of course this is an entirely different beast and will behave differently, but what is probably the biggest contributor.

Speaker impedence.
Driver size.
Amp pre both.
Room response.

Are any or all of these factors.

Not meaning to be one saying "Duh" at you, but did your other rig employ dynamic eq or any other loudness compensation? I think that's all you need for your current rig to get satisfying low level listening. Fletcher Munson curves and all that.

edit...I see the boom/tizz of the CV speakers has been addressed, perhaps they were applying sort of a built in loudness contour.

 

[JohnnieB]

Now that you mention it, I did run a Pioneer 14 band per channel GEQ on my old system. Man, that was a sweet EQ. I think the combination of current gear, as PENG stated, is a big part. Room correction, will be downloading REW this weekend. I think also the addition of a sub for low bass reinforcement will help as well. I will post an update once I tinker with REW and do some more tweeking.

agarwalro, I will neither confirm nor deny the use of halucinogenics in my younger years. Those were good times. Ever been to Amsterdam?

Thanks everyone. Sometimes it helps to confirm suspicions with people who are more knowledgable than one self.

 

[agarwalro]

ADTG swears by Audyssey DynamicEQ and I'm a big fan too. But, it only compensate for the bass. Specifically, as volume goes down it dynamically increases the low end. It makes for fuller punchy bass even at lower listening levels. The other day I tried to watch a late night movie with DEQ off and it felt very dissatisfying.

That said, Audyssey's DEQ will do nothing for mid and treble dynamics. XT32 and SubEQ on the other hand will. They are the auto room corrections for mains and subs respectively. Since they correct linear response and try to improve time domain issues, this goes a long way in improving overall dynamics. I am very impressed by XT32 and SubEQ, but ADTG prefers to keep them disengaged or run in L/R Bypass mode. So, YMMV here.

 

[PENG]

Room is 12x22x8. This is both the L.R. and dining area. I have the speakers set up on one half of the long wall due to placement constraints. I am running Ascend Sierra towers RAAL off of an Emo XPA-2.

Just curious to know if your previous system was in the same room and placed similarly as our current system?

If I understood right, from your other post you said the speakers were placed on the long wall. So that means you only have 12' wall to wall to play with your listening position. In such shape of room I think you may find moving even two feet would make a significant difference in the bass you are hearing, so in terms of dynamic and "loudness" you may like it better even if it means you end up sitting on the floor as most likely moving the couch two feet or more won't be an option for you..

Other than that, I think your current system should sound really good once you accept the fact that your previous CV speaker based system may sound more exciting due to the exaggerated highs and lows, they really couldn't and shouldn't be compared to what you have now.

To get it up another significant notch in terms of SQ (again, meaning more accurate/less colored live like sound), you need to get Audyssey with DEQ (Dynamic EQ) or equivalent REQ system especially if you enjoy low volume listening. REW is great in saving time to do sweeps and stuff to figure out what you are getting in your room but IMHO it is far easier and better to just leave it to Audyssey XT32 plus DEQ or the Anthem ARC system that their users typically think is superior to Audyssey.

For movies, no matter what you do your speakers simply can't do justice to anything below 35 or even 40 Hz without the help of a good subwoofer. Are you using only two channels, seeing that you Sherbourn is a 7.1 prepro?

 

[JohnnieB]

Yep just two channels. I started this sound system build after I lost my last setup in divorce. At first I was PISSED that she got stuff that belonged to me before we ever met. Then I realized, it was just stuff. Now I have a fresh start and can build a better system.

It's not in the same room or even the same house. Yep, you guessed it, she got that too. I would liked to have set it up so the fronts were on the short wall facing the length of the room. Alas, the house was built in the 30's and people didn't think about such things then. In truth, it had more to do with the leather sectional my girlfriend wanted. This is a rental, it's cheap for now. I'll be looking to buy a house again. A bigger house. That's why I went with towers instead of bookshelves. I have always preferred towers anyway. Eventually it will be 5.2, maybe 7.2 someday who knows.

I got the Sherbourn, even though it didn't have room correction, because it didn't have all the other features I didn't need as well. Current receivers have too much c**p I don't need and not enough of what I do. I'm kinda old skool that way. Reviews were excellent as far as sound and video quality. Plus I got it for 700 bucks new.

I realized the first time I heard the Ascends, that a speaker with a flat response, was a whole different breed than what I was used to. I loved them immediately. But now that I've had them a few months, I'm not turning them up as loud, fanning my feathers so to speak. I'm settling back into old habits of mellow listening well into the night. Still rock out about once a week tho. At first, I was a little surprised by lack of bass with the Ascends. After having them a while, I realize they don't lack bass, it's just accurate. To get the lower octaves that I love, I NEED a sub.