Downside of sealed cabinets?

madfloyd

madfloyd

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I'd like to know if what I think I'm experiencing (i.e. what I'm perceiving) is a known drawback of sealed cabinet speakers.

I've noticed with my Magico S5's that when I raise the volume past a certain threshold the tonal balance changes - the bass stops getting louder - it sort of 'compresses' - and the result is that it sounds too lean (e.g. highs too pronounced, bass too weak).

Is this normal for sealed cabinets?

I should point out that the volume threshold I'm referring to is about 88-90db (lest somebody think I'm playing at much higher levels than that).

As a result, I won't play these speakers loud because it doesn't sound great. Clean, but the imbalance destroys my enjoyment.

Comments?
 
I don't experience that here. The S5s linearity is one of its features compared to many other speakers.

Sounds to me like the amplifiers are running out of steam more than room acoustics. I know you own PASS amplifiers Ian but any chance they might be unhappy with the Magico's load?
 
I understand what you mean Myles, but it's hard to imagine a sealed box speaker presenting a load that would be easier for a tube amp compared to SS, especially something like the XA's that are designed to be stable to at least 2 ohms.
 
I have to agree with Miles on this one, although I don't know about SS vs. tubes. Maybe it's just a mismatch with Pass, for whatever reason.

Any local friends who can lend you an amp or two with which to compare?
 
rbbert said:
I understand what you mean Myles, but it's hard to imagine a sealed box speaker presenting a load that would be easier for a tube amp compared to SS, especially something like the XA's that are designed to be stable to at least 2 ohms.
Click to expand...

Know this was for the older model but read paragraphs 5 and 7.

http://www.theabsolutesound.com/articles/pass-labs-xa160-and-x6005-monoblock-power-amplifiers/

And JA's measurements for older amplifiers:

http://www.stereophile.com/content/pass-labs-xa160-monoblock-power-amplifier-measurements

Thing is tubes will lose power, not necessarily sound bad. Remember also how Russ's Spectral amps shut down driving his Martin Logans while never had an issue with my cjs.

Another thing that I thought of is there might be an issue if Ian's PLC/power cords are limiting current delivery. Sometimes those issues won't show up except under very demanding circumstances. I would for S&G, unhook the amps from the PLC and plug the equipment straight into the wall.
 
Oh, I can't wait for AJ to chime in on this one. I can hear him saying "tragic cone & dome" right now.

Ian - I can't for a minute think the amps are having any issues. Your amps are putting out north of 320 watts of pure class A.

I think you MIGHT be hearing the limitations of a sealed speaker....but I don't know.


Sent from my iPhone using Tapatalk
 
I agree with Mike, I do not see your Pass amps having difficulty.

Another strange thing, When Canada's National Research Council tested the S5 in its anechoic chamber, the reverse occurred. The tweeter started to compress before the woofers at 95db, they were down 1.5 db at 5k 2.5 db at 10k relative to the bass and midband compared to results at 70 db, at 90db maybe down a db in the upper frequencies.

But you can never argue with what you are hearing. why are you getting these results? not sure. Maybe its a room thing.
 
320 watts of Class A power? I think that is a wee bit on the high side. Are you adding both channels together? Anyway, all amplifiers aren't created equal with regards to which load they can deliver their maximum amount of power and current into regardless of whether they are SS or tube amps.

i just checked the Pass website and these amps are rated for 320 watts into 4 ohms, but I can promise you those won't be 320 Class A watts into 4 ohms continuous. But still, that's a lot of power.
 
It is very interesting to listen to these comments within the context of the concurrent Raidho D3 conversation occurring on another thread ( A Plea to Michael B.).

Sealed box versus ported. Two phenomenal speakers with polar opposite bass results at high spl's. It is so hard to achieve perfection across rooms, amps and sources.

I think we should get Madfloyd's S5's and Mark's D3's in a room together. Maybe a little candlelight, champagne, a little Marvin Gaye and we can procreate the perfect speaker.....the Magic-Ho SD-8. Not to lean, not to boomy....just right.
 
Mike said:
Oh, I can't wait for AJ to chime in on this one. I can hear him saying "tragic cone & dome" right now.
Click to expand...
Hah!, that does sound like something I would say. I see Jeff's been talkin' :P

madfloyd said:
I've noticed with my Magico S5's that when I raise the volume past a certain threshold the tonal balance changes - the bass stops getting louder - it sort of 'compresses' - and the result is that it sounds too lean (e.g. highs too pronounced, bass too weak).

Is this normal for sealed cabinets?
Click to expand...

Hi Floyd,

No, this is not normal/inherent for sealed cabinets. This is case specific. Every loudspeaker has a "sweet area" position in room, where the speaker/room interaction bass response, will be (hopefully) balanced at the listeners seat/ears.
Luckily, for your speaker, we have some nice data courtesy of Soundstage to look at. Please do not read this as a slam against Magico, or the S5, from a "other manufacturer". Measurements are objective, (mis)interpretations can be subjective!:)
S5 anechoic FR:
attachment.php

Clearly you can see that below 500hz or so, where the room will tend to add some reinforcement, the S5s response actually tapers downward a bit, to around 40hz, where it then drops off. What this means is that in a typical room, one might have to position the speaker relatively close to the front wall, to bring up the bass boundary reinforcement and make the speaker sound balanced. This is going to be very room dependent of course. I have heard that model at a show (hotel room) sound quite balanced and I've heard it at a friends house...sound a bit thin, almost exactly as you describe.
I had to dig deep, but found another sealed design on Soundstage, the NHT Classic Three
attachment.php

Notice how the response rises gently below 500 Hz, before falling off below 70 Hz or so. This speaker would sound more balance a bit further out into the room.
IOW, it's not a "sealed" issue, its a specific speaker/room/placement issue.
Regarding the "compression" issue, couple thoughts. Our hearing perception changes with volume, not just speakers!:) (I'm sure you're familiar with Fletcher-Munson loudness contours etc).
The same Soundstage measurements show the S5 holds up quite well in the bass at higher levels:
attachment.php

Not surprising, given the dual 10" long stroke woofers. If anything, it's the treble that will compress, not the bass.
I know it may not result in as good imaging, but as an experiment, try moving the speakers back closer to your front wall and see if it doesn't sound spectrally more balanced.

cheers,

AJ
 

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I agree with Myles. My experience is the s5 bass scales. I believe it is a matter of impedance and load matching with amp.
 
Ian,

Have your Transparent Ref XL SCs been calibrated for the Pass amps and Magico S5s?
 
mep said:
320 watts of Class A power? I think that is a wee bit on the high side. Are you adding both channels together? Anyway, all amplifiers aren't created equal with regards to which load they can deliver their maximum amount of power and current into regardless of whether they are SS or tube amps.

i just checked the Pass website and these amps are rated for 320 watts into 4 ohms, but I can promise you those won't be 320 Class A watts into 4 ohms continuous. But still, that's a lot of power.
Click to expand...
The website info may not be 100% accurate. The information I just got from Mark at RenoHiFi (a booklet) says peak Class A power is indeed 320 watts/channel at 4 ohms, with 6 db of Class A/B headroom above that (i.e. 1280 wpc at 4 ohms).
 
rbbert said:
The website info may not be 100% accurate. The information I just got from Mark at RenoHiFi (a booklet) says peak Class A power is indeed 320 watts/channel at 4 ohms, with 6 db of Class A/B headroom above that (i.e. 1280 wpc at 4 ohms).
Click to expand...

Peak power isn't average power.
 
Dpod4 said:
I agree with Myles. My experience is the s5 bass scales. I believe it is a matter of impedance and load matching with amp.
Click to expand...
Hmm, you may both be onto something there.
I searched for the XA160 (v1 ?) and found this rather surprising (to me) data from Stereophile:
attachment.php


The output drops precipitously into lower impedances! Now, there is some mention of this being changed and maybe the .8 is different, but....
Coupled with the S5s almost 2 ohm minima in the bass:
attachment.php


Would be a recipe for light bass at elevated levels....

cheers,

AJ
 

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That's why I said all amps are not created equal with regards to how much power they can put out into a given load. Sometimes phase angles cause issues with amps as well.
 
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