Adcom 5500 and 555MKII

[enigmasse]

I have a pair of Klipsch Pro La Scalas and they are harshly bright. I love the dynamic range of these speakers though my ears can only take so much! Right now I am pushing them with a 100w cheap Sony (STR-DE135) but looking for an upgrade.

I have been looking at either trying to get a hand on an Adcom 5500 or 555MKII. Looking at the manuals, it appears that the older 555MKII has lower distortion and overall better specifications than the newer MOSFET Adcom 5500. Why would this be the case? I would presume the newer amp would have better specifications.

What can I do about the brightness? Many tend towards a tube hybrid (solid-state amp/tube pre-amp) to get a good warm sound. I am looking for accuracy in stereo music listening, something good in all varieties of music. I have already heard that accuracy and tubes shouldn’t be in the same sentence. Any ideas on these two amps and how it may affect the brightness?

 

[mtrycrafts]

I have a pair of Klipsch Pro La Scalas and they are harshly bright. I love the dynamic range of these speakers though my ears can only take so much! Right now I am pushing them with a 100w cheap Sony (STR-DE135) but looking for an upgrade.

I have been looking at either trying to get a hand on an Adcom 5500 or 555MKII. Looking at the manuals, it appears that the older 555MKII has lower distortion and overall better specifications than the newer MOSFET Adcom 5500. Why would this be the case? I would presume the newer amp would have better specifications.

What can I do about the brightness? Many tend towards a tube hybrid (solid-state amp/tube pre-amp) to get a good warm sound. I am looking for accuracy in stereo music listening, something good in all varieties of music. I have already heard that accuracy and tubes shouldn’t be in the same sentence. Any ideas on these two amps and how it may affect the brightness?

You can start by testing what that speaker response really is in your room. Then, EQ it and acoustic treat the room.
Another amp will not solve frequency issues.
Your Sony should have no problem driving those speakers, none.

Hard to say how those two amps were tested but I seriously doubt there are audible differences between them.

 

[audiofox]

I recently owned both an Adcom 555 Mk 2 , which uses bipolar output transistors, and a 5503, which is the same basic design as the 5500, using MOSFET output devices, but with 3 channels. There was a subtle difference between the two amps, with the 5503 having a somewhat "warmer" sound than the 555 II, using the same speaker setup in the same room with no other differences inserted (ie, same furnishings, speaker cable, etc, etc). Personally, I give much more importance to the quality of the power supply-an inadequate or improperly designed PS will have a bigger negative impact on an amp's performance than the selection of a specific output device, particularly if there is not enough capacity or current capability to keep the devices in their performance "sweet spot", which is different for bipolar vs MOSFET transistors.

Having said that, I agree with mtyrcrafts-your room acoustics are likely to have a much bigger impact on speaker brightness (or bass resonance) than any specific amplifier. I am an electrical engineer by profession and did my senior paper on acoustic response and design of auditoriums, so I am hesitant to recommend any amp without some specific data behind the recommendation-"warmness" and "liquidity" are much too subjective with which to base any serious purchasing decisions, since one person's "warmth" is another person's distortion. If you can verify that your room is optimized for your speakers (hard to do without lots of response testing and empirical adjustments to the room itself), then you can move to the electronics if you still want to try to improve the sound. Even though the room response is hard to get correct, if you have time, it is still cheaper than investing in a load of amps in the hope that you can solve your problem, especially if the problem is not the electronics.

 

[mulester7]

I have a pair of Klipsch Pro La Scalas and they are harshly bright. What can I do about the brightness? Many tend towards a tube hybrid (solid-state amp/tube pre-amp) to get a good warm sound.

.....now you're thinking in the right direction....and you don't need an EQ with any good set of speakers....they are tuned to have slight + and - swings along their full range on purpose....

 

[Nuglets]

I would have to agree with MTRY. I just read a bunch of consumer reviews about these speakers and many people say that they require expensive equipment otherwise they sound like crap. That couldn't be farther from the truth. Like MTRY said, check out the frequency response you are getting in your room if possible, and try to tame any large peaks with speaker placement and/or an EQ. Also, if you aren't satisfied at all with the sound out of your reciever, make sure there are no DSP, or any wierd EQ's built in you reciever that are on and coloring the sound. Find a 2 channel stereo mode with no equalization to listen to music and start there. I don't know what kind of experience you have with Home Theaters and Stereos, but I know that many people misunderstand the use of tone controls and equalization. Be conservative when "boosting" any tone controls or EQ settings as most nulls/dips in the frequency response are created by cancellations caused by the room itself, not the speakers or reciever. I wouldn't take any of the advise that I have read in the consumer reviews of those speakers. Ask questions here and you will learn far more than you ever imagined about the subject if you are interested.

 

[Nuglets]

.....now you're thinking in the right direction....and you don't need an EQ with any good set of speakers....they are tuned to have slight + and - swings along their full range on purpose....

I think you are forgetting about room acoustics coloring the sound by creating "peaks" and "dips" in the frequency response. I agree that an EQ isn't needed for good sound, but without room treatment it can help assuming it's being used correctly.

 

[mulester7]

I agree that an EQ isn't needed for good sound, but without room treatment it can help assuming it's being used correctly.

.....total agreement.....

 

[Nick250]

My usual comment, almost everything you hear in your listening room is a combination of speaker choice and room acoustics. One can love a speaker when auditioning at the dealer, and find it much less to one's liking at home. That's room acoustics. There are a couple of solutions.

1. Return the speaker to the dealer and and find a different speaker to do an in home test.

2. Get in touch with one of the vendors that advertise here at AH and discuss room treatments. Room treatments are just about the only thing can provide the proverbial "night and day" difference in the sound.

As mention above these two items contribute 80% to 90% (my guesstimate, no supporting data) of your sound so really focus on room acoustics.

3. Electronically EQ your speakers for your room. This can make an audible improvement, but not to the extent of 1 & 2 above. FWIW in a conversation with someone in the recording business I was told that the speakers in a recording studio are EQed to an inch of their life. Not sure if that's relevent, but interseting none the less. My Denon 3806 receiver has Audyssey Auto EQ. It made a difference to my ears (you can turn the Auto EQ on and off in seconds so it's an easy test). The sound was little bright, now it is less so. Also the sound stage is seamless with Audyssey turned on, a bit less with it off. That's my experience.

Good Luck!

Nick

 

[mtrycrafts]

I recently owned both an Adcom 555 Mk 2 , which uses bipolar output transistors, and a 5503, which is the same basic design as the 5500, using MOSFET output devices, but with 3 channels. There was a subtle difference between the two amps, with the 5503 having a somewhat "warmer" sound than the 555 II, using the same speaker setup in the same room with no other differences inserted (ie, same furnishings, speaker cable, etc, etc). Personally, I give much more importance to the quality of the power supply-an inadequate or improperly designed PS will have a bigger negative impact on an amp's performance than the selection of a specific output device, particularly if there is not enough capacity or current capability to keep the devices in their performance "sweet spot", which is different for bipolar vs MOSFET transistors.

Having said that, I agree with mtyrcrafts-your room acoustics are likely to have a much bigger impact on speaker brightness (or bass resonance) than any specific amplifier. I am an electrical engineer by profession and did my senior paper on acoustic response and design of auditoriums, so I am hesitant to recommend any amp without some specific data behind the recommendation-"warmness" and "liquidity" are much too subjective with which to base any serious purchasing decisions, since one person's "warmth" is another person's distortion. If you can verify that your room is optimized for your speakers (hard to do without lots of response testing and empirical adjustments to the room itself), then you can move to the electronics if you still want to try to improve the sound. Even though the room response is hard to get correct, if you have time, it is still cheaper than investing in a load of amps in the hope that you can solve your problem, especially if the problem is not the electronics.

I think you might be interested in this:

David Rich and Peter Aczel, 'Topological Analysis of Consumer Audio Electronics: Another Approach to Show that Modern Audio Electronics are Acoustically Transparent,' 99 AES Convention, 1995, Print #4053.

 

[audiofox]

I think you might be interested in this:

David Rich and Peter Aczel, 'Topological Analysis of Consumer Audio Electronics: Another Approach to Show that Modern Audio Electronics are Acoustically Transparent,' 99 AES Convention, 1995, Print #4053.

mytrycrafts, do you have a URL for this article?

 

[enigmasse]

The room the speakers occupy is 13.5'x16.5'. The only thing in the room is a cloth couch that is hard. The materials used in the room is glass, tile and drywall. The ceiling slopes from 8' to 14' feet.

I have started reading: http://en.wikibooks.org/wiki/Engineering_Acoustics/Basic_Room_Acoustic_Treatments#Introduction on how I can acoustically treat the room.

Looks like I have a lot of experimenting ahead though after reading, I do not know where to start without making the room unappealing.

 

[mtrycrafts]

mytrycrafts, do you have a URL for this article?

Sorry, I have not seen it on line. AES has it.

 

[mtrycrafts]

Looks like I have a lot of experimenting ahead though after reading, I do not know where to start without making the room unappealing.

Well, some of the acoustic panel makers do have nicely designed ones that would look good as well. It sounds like your room is certainly the issue, nothing to absorb or properly diffuse sound. Like an echo chamber.

 

[enigmasse]

You can start by testing what that speaker response really is in your room. Then, EQ it and acoustic treat the room.

What is the easiest method of testing the frequency response of a room?

 

[Nuglets]

You can buy a Radio Shack SPL meter and a test cd with tones at different frequencies. I know that there are a few different cd's out there, which I am unfamiliar with, so hopefully some other's in the forum will give you some ideas of their preferences. You will want to graph the results. You want a flat horizontal line which indicates a flat frequency response. I also have a computer program called TrueRTA, which requires a microphone that you can plug into your computer and place at the listening position. The demo version only has a 1 octave resolution so the Level 2 of the program or up would be ideal.

 

[mtrycrafts]

What is the easiest method of testing the frequency response of a room?

That would depend on how much you want to get into testing.

There are computer programs to use; some are free. But, you need to involve your computer. You would need the proper mic, etc. You would need to research this avenue more.
Or, do what was posted with a test disc and RS spl meter.

So, depending how serious you are, how deeply you want to get involved will dictate what you will research and get.

 

[enigmasse]

.....now you're thinking in the right direction....and you don't need an EQ with any good set of speakers....they are tuned to have slight + and - swings along their full range on purpose....

They don't strive to be flat?

 

[JoeE SP9]

The room the speakers occupy is 13.5'x16.5'. The only thing in the room is a cloth couch that is hard. The materials used in the room is glass, tile and drywall. The ceiling slopes from 8' to 14' feet.

I have started reading: http://en.wikibooks.org/wiki/Engineering_Acoustics/Basic_Room_Acoustic_Treatments#Introduction on how I can acoustically treat the room.

Looks like I have a lot of experimenting ahead though after reading, I do not know where to start without making the room unappealing.

With a room like that it's no wonder your speakers sound bright and harsh. Put some rugs on the floor. Hang some oriental rugs or tapestries on the walls. Almost any speaker would sound bright and harsh in a room furnished like that.

 

[mulester7]

They don't strive to be flat?

.....no, Enigmasse, they don't....some call it a speaker's sonic signature....the guy who made my speakers says a totally flat +/- 0 db speaker sounds neutered, with no life....he says you want +/- 0 db through ALL the electronics right up to the speakers, and then the tuning of the speaker gives it's own interpretation or sonic signature....I've wondered about this one myself, but listening to the speakers I have which are +/- 1.7 db according to the maker, says he knows what he's doing....they are 80 lb. two-way floorstanders and 52 lb. two-way bookshelves, and have the best life-like low-mids-up I have ever heard pushed by McIntosh....with subs, or in my case, bass seperates, I feel as though I am drawn INTO the music and DVD's.....

.....edit....WHOA, LUKE LIKTA' GOT ME WITH THAT LIGHT SABER.....

 

[Nuglets]

Why would a speaker sound lifeless with a flat frequency response? My interpretation of "flat" is: If a sine wave is output at frequncy "F" at a given amplitude, at "F+x"(x=any real number) it's output is the same amplitude.. In other words, sine wave's at different frequencies, with the same amplitude should be equal in relation to each other. When actual sound is played, the sound will not be "flat", but exactly as the engineer intended it to be, assuming he/she is using equipment with a flat response. That is what I understand to be "flat".

I also noticed that you mention speakers with +/- 1.7 dB response, which I think is very close to 0. Perhaps as close to 0 as they can get throughout the entire frequency range that they are capable of playing in.