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Holographic Soundstage ?

I would like to share my observation and hopefully get some input from people who have the same interest.

My system consist of Wharfedale Opus 3 , Krell KRC-3 preamp, Krell KSA 150 amp, Chord Qutest DAC and a computer with JCAT USB EX running Roon/with LPSU from HDPlex.
I mainly like holographic soundstage and would be able to achieve a very good 3D soundstaging with my current Krell setup.
I decided to try out tube amp a couple days ago because I read through the internet and everybody told me that tube amp always have better holographic soundstage and 3D imaging comparing to SS amp.
So I order a Raven Blackhawk MK3 from Raven audio with 45 days home trial just to try it out. I was expecting a very holographic soundstage that will blow my Krell out of the water.
Well, I was so WRONG. The Krell combo actually has a deeper and wider soundstage comparing to the Raven.
The Raven also has some very weak bass comparing to the Krell which is more punchy and tonally rich textured bass.
I cannot understand why it happens. I am always under the impression that tube amp will always provide more holographic soundstage. Obviously, In my set up the Krell is superior when it come to 3 dimensionality.

I will keeping trying out the Raven Blackhawk in the next couple of weeks and if things are not improved. I am ready to return the Raven and perhaps trying out the other tube amps (or solid state amps) that can beat the Krell combo.

If any one has some idea of such a product, please let me know. I am looking for an upgrade right now.

128x128viethluu
mozartfan
2,143 posts
 
millercarbon9,062 posts04-30-2021 12:47pmYour speakers at 91dB are not awful but are below my (admittedly totally arbitrary) cutoff of 92dB that anyone should consider before buying any speaker


~~~~~~~~~~~~~~~~~~~
As you know i’ve also made this very same opinion all over audiogon these past weeks.
Sensitivity is everything ina speaker’s performance.
However, there are ~~The Exception To This Golden Rule~~

Seas has their Excel woofer line, rated 85-88 db sens.
Yes this  goes against my cutoff db sens at 92/93  as acceptable.
Due to the voicing in the lower midrange.
any woofer can make solid bass.
But very few can voice pure lower mids, in conjuction with solid low bass. .
Seas accomplishes this rare blend in their unique Excel line of woofers.
Now even Scanspeak has a woofer than can match.
Now as for upper mids/highs, here i am with you, 92db is the line in the sand for voicing this crucial fq range.
mozartfan
2,143 posts
 
Seas Excel dome tweets The Millennium and their new flagship Cresendo are rated 87db, Thats 5db too low. I'm sure the new Cresendo beats out the Millennium, but not enough to give a  cigar.
For voicing mids/highs witth a  ~~3 dimensional soundstage~~, only a  high sens FR  are designed for this task. 
I know Troels is suck on using midranges, 3 wyas, etc, but note his xovers....Massive and very complex = drivers are faulty.
A high quality FR  does not suffer these liabilities needed complex xovers.
We  must appreciate Troels excelent work supporting xover designs. But sad to say these things are dated.
The Seas Thor bass xover is simple
1 resistor, 1 cap, 1 coil.  Exception to the rule. 
You do not wanta  woofer witha  92db sensitivity, it would be too over whelming in the fabric of the soundstage. 
I am about to take  a  chance on swapping oit the lower W18E001 fora  W22 Graphene. Its a $900 gamble, bass might be too heavy in the overall soundstage. 
We are looking for a balance.
Yes I am aware my New Thor design witha  FA22RCZ at 94db + dual W18E001 @ 87db, might seem out of sync.
But remember its DUAL W18E001. Thats alot of bass for 1  channel.
The FA22RCZ's arrive tomorrow, I have a   test cabinet .
The 2 chinese FR a 4 and 5 inch arrive next week. 



mozartfan
2,143 posts
 
Caveat:
The Seas midtweets are acceptable for light jazz, \
Not for complex jazz ensembles nor full orchestra. 
jjss49's avatar
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jjss49
6,612 posts
 
the blackhawk amp is not driving the speakers properly

reading a single numerical impedance rating from a speaker maker is a fool’s game, as impedance varies by frequency (see any impedance plot vs frequency measured in a proper review), and an average impedance is pretty much meaningless, especially if you are using a low powered amp

clearly based on the driver set (2x 10 in) of the op’s speakers, the impedance is dipping low, probably well below 4 ohms, in the bass, due to the dual woofer configuration - this speaker needs current drive in the bass

the 20wpc tube amp, 2 6l6 power tubes per side, doesn’t stand a chance
atmasphere's avatar
atmasphere
11,948 posts
 
@viethluu  @jjss49  is correct, it appears that the KEF loudspeakers are not a good load for this particular tube amp. If you look at the speaker you see that has a dual woofer array- so its nominally a 4 ohm load in the bass.

For this reason you should be using the 4 ohm taps IMO/IME. But its a simple fact that speakers designed this way are not intended for tube amps, which don't do well on 4 ohm loads. This is because the output transformer is less efficient on 4 ohm loads and not only will run hotter (absorbing amplifier power) but it may well lose as much as an octave of bandwidth on the bottom end!


If you really want to hear what tubes are about (and to also get lower distortion out of your Krells, which won't hurt) you would need to have a speaker that is at least 8 ohms in the bass to make a more valid comparison.


Put another way I suspect that because of the load of your speakers you are for more likely to get good results from solid state than tubes, but even solid state suffers because while it can drive the load easily enough, to do so it makes more distortion, which obscures detail (including soundstage information).
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