Rotel RB-870BX vs class D (hypex/Purifi…)

[DanielT]

Thanks for the test. I listened to X and Y a few times, I hear a subtle difference in the treble and upper mids in favor of X. Where is the link to this test?

You’re well on your way. Now all that remains is to use something like Foobar.

(Gemini AI)

foobar2000: Components Repository - Random Pools

foobar2000

www.foobar2000.org

Here is the link you asked for; see post #2, for example, regarding Foobar:

Do all amplifiers sound the same? Level matched listening test

Do all amplifiers sound the same? Level matched listening test One more to this neverending discussion. Two very different amplifiers are tested, however both with very flat frequency response in the audio band. The test level is set such that 0dBFS of digital data corresponds to THD = 0.9% for...

www.audiosciencereview.com

 

[Janox]

Definately here is more going on than just comparing two amps:

View attachment 557494
Frequency response is nowhere near the same. That's just two linear amps being compared.

Never mind that the level matching is way, way off

Thanks for the analysis, I'm still learning. The volume was compared with a 1kHz test signal before recording, I didn't make any other settings or adjustments. But I think it may correspond to the different frequency balance of the two amplifiers, which is audible. Which color is A and which is B?

 

[DanielT]

It is the loudspeaker making sound. If this should be improved with new ones the budget is too small. Sorry.

What? Don't you think that, for instance, the models suggested in the thread—such as the passive HECO Aurora 1000/700 speakers

Or the active Neumann KH120 II speakers
(assuming the OP sells their current speakers and amp and adds the proceeds to the budget)

...wouldn't represent a decent upgrade in sound quality compared to the TS's current PMC GB1 speakers?

 

[SSS]

What? Don't you think that, for instance, the models suggested in the thread—such as the passive HECO Aurora 1000/700 speakers

Or the active Neumann KH120 II speakers
(assuming the OP sells their current speakers and amp and adds the proceeds to the budget)

...wouldn't represent a decent upgrade in sound quality compared to the TS's current PMC GB1 speakers?

Since I did not hear the speakers I can't tell. But the Neumann is a near field monitor and thus be sitting near the speaker. Heco since decades made good price/performance speakers, not hi-end in the earlier times. With the Heco it may be better sound since 3-way and 2 bigger bass drivers. Could be tried and with the intended budget it may come out satisfactory. As I am in the similar age of Vincia I know what I can hear and what not. In general it is a lack of highs above 11 kHz and a droop in the upper mids. To make a natural sound either the tone controls need to enhance these regions and the loudspeakers need to be able to reproduce the higher power. Or the loudspeaker themselves enhance the upper mids and the highs which is of course against the flat rule. A sidekick, transmission line loudspeakers work really well when designed properly, but needs big tall cases. This does not help to sell them and instead most manufactorers use bass reflex with its own problems.

 

[Vincia]

Since I did not hear the speakers I can't tell. But the Neumann is a near field monitor and thus be sitting near the speaker. Heco since decades made good price/performance speakers, not hi-end in the earlier times. With the Heco it may be better sound since 3-way and 2 bigger bass drivers. Could be tried and with the intended budget it may come out satisfactory. As I am in the similar age of Vincia I know what I can hear and what not. In general it is a lack of highs above 11 kHz and a droop in the upper mids. To make a natural sound either the tone controls need to enhance these regions and the loudspeakers need to be able to reproduce the higher power. Or the loudspeaker themselves enhance the upper mids and the highs which is of course against the flat rule. A sidekick, transmission line loudspeakers work really well when designed properly, but needs big tall cases. This does not help to sell them and instead most manufactorers use bass reflex with its own problems.

The budget was for an amplifier. For the speakers I can double it. But I have constraints on size. The footprint, including the base and spikes, must not be larger than 20-22cm (W) by 26-28cm (D). The bass reflex port does not have to be rear because the speaker will be positioned against the wall.

For now I have only identified Proac DT8 (4 ohm; 90 dB; downfiring). I ask if the Rotel RB870BX is still suitable to power this Proac. Do you think I don’t need a sub and I can also resell the Kef Kube 12B sub?

 

[DanielT]

Since I did not hear the speakers I can't tell. But the Neumann is a near field monitor and thus be sitting near the speaker. Heco since decades made good price/performance speakers, not hi-end in the earlier times. With the Heco it may be better sound since 3-way and 2 bigger bass drivers. Could be tried and with the intended budget it may come out satisfactory. As I am in the similar age of Vincia I know what I can hear and what not. In general it is a lack of highs above 11 kHz and a droop in the upper mids. To make a natural sound either the tone controls need to enhance these regions and the loudspeakers need to be able to reproduce the higher power. Or the loudspeaker themselves enhance the upper mids and the highs which is of course against the flat rule. A sidekick, transmission line loudspeakers work really well when designed properly, but needs big tall cases. This does not help to sell them and instead most manufactorers use bass reflex with its own problems.

Fair enough; you can't simply say that Person X will prefer Speaker Y just because Y measures better than the ones being replaced. In other words, it’s not a 100% certainty, even if the odds are high.

Neumann KH120 II are near-field monitors, but they should work well at the TS's/ Vincia's listening distance of 2.5 m (8 ft) too.

That said, if Vincia tries plugging the ports on his TL speakers to make them sealed, it might improve the sound enough for him to like them (even more). See: #42–#46.

Okay, I see now that Vincia can double his speaker budget. That changes things.

 

[Vincia]

Okay, I see now that Vincia can double his speaker budget. That changes things.

Of course things change with the budget, but first (as soon as I’m able to do it) I’ll do the tests by closing the transmission line. In fact, in this way I would make a system with two satellites (170-20k) with a self-powered sub (~35-150 hz). However, from the opinions provided so far by the members of the forum, I conclude that no one believes that I would benefit by changing Rotel, which was my starting point.

 

[melomane13]

"The €4,000 budget is substantial, but the rather limited dimensions severely restrict the possibilities. I also suspect that the 'industrial' look of pro speakers wouldn't go down well with the rest of the family. I would therefore stick to passive bookshelf speakers, keeping the subwoofer and amplifier." Kef R3 meta 2400€ in blue / white / black / wood. The bass-reflex port is in the back, but foam bungs are supplied.

 

[Vincia]

"The €4,000 budget is substantial, but the rather limited dimensions severely restrict the possibilities. I also suspect that the 'industrial' look of pro speakers wouldn't go down well with the rest of the family. I would therefore stick to passive bookshelf speakers, keeping the subwoofer and amplifier." Kef R3 meta 2400€ in blue / white / black / wood. The bass-reflex port is in the back, but foam bungs are supplied. View attachment 557521

336 mm (with terminal)
What about Proac DT8?

 

[melomane13]

Et le Proac DT8 ?

I haven't listened to ProAc DT8, there are no reviews from Erin or ASR, and they don't have a waveguide on the tweeter or a coaxial driver, which are essential for good directivity. They also make questionable engineering (or marketing) choices, like the off-center tweeter or two different woofers in a 2-way design... Anyway, I don't find them interesting, especially given the price.

 

[voodooless]

The volume was compared with a 1kHz test signal before recording

Using what? An SPL meter isn’t good enough, not by a long shot. And what I see here is way worse than that. Use an AC voltmeter and match within 0.1V or better.

I didn't make any other settings or adjustments. But I think it may correspond to the different frequency balance of the two amplifiers, which is audible. Which color is A and which is B?

These amps should not have any frequency response deviations. Both were measured here, both were linear. So something is clearly off here.

 

[Janox]

Using what? An SPL meter isn’t good enough, not by a long shot. And what I see here is way worse than that. Use an AC voltmeter and match within 0.1V or better.


These amps should not have any frequency response deviations. Both were measured here, both were linear. So something is clearly off here.

I used AC voltmeter for precise adjustment. Could there be a problem with the output LC filter in combination with the speakers? The difference in frequency response is audible.

 

[voodooless]

The difference in frequency response is audible.

I’m sure it is. It should however not be there.

 

[SSS]

The budget was for an amplifier. For the speakers I can double it. But I have constraints on size. The footprint, including the base and spikes, must not be larger than 20-22cm (W) by 26-28cm (D). The bass reflex port does not have to be rear because the speaker will be positioned against the wall.

For now I have only identified Proac DT8 (4 ohm; 90 dB; downfiring). I ask if the Rotel RB870BX is still suitable to power this Proac. Do you think I don’t need a sub and I can also resell the Kef Kube 12B sub?

The Proac DT8 is sensitive which means the amplifier power is saved. Since I don't know the bass response it is hard to decide whether the sub speaker can be omitted? Your space requirement is a some kind limiter as well that the reflex port needs not to be in the rear of the box. Placing direct at the wall will increase bass. Personally I do not like sub speakers because there is no real musical contribution, it is boom boom for me. Depending on the music you hear bass may necessary especially for grand symphony orchestra with cattle drums and double bass.

 

[stuartkohl]

Digital amplifier technology has not progressed much in twenty years. I made a comparison of the new Topping Mini 300 against the twenty-year-old Panasonic D-class AV receiver (I put it on YouTube). According to my findings, class D amplifiers still sound somewhat harsh on high tones and higher mids. A good AB decade-old AB amplifier still sounds more natural in classical music. The class D amplifier impresses with a lot of details at first listen, but after a long listen it becomes tiring and unnatural.

I haven't done proper testing, but I've compared the Topping Mini 300 and Buckeye Hypex NCx252MP to both old and new AB amps and there certainly isn't any hardness with the Class D amps. There isn't really an observable difference in sound quality between any of these IMO.

As I said, I haven't done proper testing, just uncontrolled, sighted listening comparisons. However, I'm going to stick with the Buckeye amp since it has plenty of power, seems to be very transparent, runs very cool, and doesn't use a lot of electricity like Class AB amps tend to do. What's not to like about that?

My recommendation for the OP would be to look at getting new speakers rather than a new amplifier. Unless your current Rotel amp is broken somehow, it's unlikely that a newer amplifier will be an actual improvement.

 

[mglobe]

You might check out the Buchardt standmounts. S500MK3 or E50. Should be readily available for you.

https://buchardtaudio.com/collections/passive-speakers


Slightly different chart than what I posted before, but shows the linearity, particularly of the E50, and good low end on the E50 as well. On a speaker stand I would expect the dimensions to fit for you, but check that out. The 50’s are over your budget, but look really good both in terms of frequency response and in terms of look to my eye.

Buchardt has a try at home program with a 100euro return cost

 

[Vincia]

You might check out the Buchardt standmounts. S500MK3 or E50. Should be readily available for you.

https://buchardtaudio.com/collections/passive-speakers


Slightly different chart than what I posted before, but shows the linearity, particularly of the E50, and good low end on the E50 as well. On a speaker stand I would expect the dimensions to fit for you, but check that out. The 50’s are over your budget, but look really good both in terms of frequency response and in terms of look to my eye.

Buchardt has a try at home program with a 100euro return cost

View attachment 557576

S400 MK3

 

[melomane13]

S400 MK3

Nice, nice, very nice!
A great, excellent 7.5-inch SB Acoustics SATORI MW19P-8 woofer, with a nice waveguide.
The performance gap compared to your current speakers is a given.

 

[DanielT]

The Ascend Sierra-1 V2 has received great reviews. It is a nice, compact bookshelf speaker with a classic look—reminiscent of older speaker looks—yet developed using modern technology (the Klippel NFS measurement system).
It has a rear port, but since you’re using a subwoofer, you can simply plug that port.

What was really nice was the spatial qualities of the speaker. Its wide directivity meant it projected a large halo around the single speaker I was listening to. This, combined with the tiny tweaks above made for stunning presentation at times. Some of my reference tracks sounded so good that my jaw fell on the floor!

US $998 per pair

Ascend Sierra-1 V2 Speaker Review

This is a review, listening tests, EQ and detailed measurements of the Ascend Acoustics Sierra-1 V2 bookshelf speaker. It is on kind loan from a member and costs US $998 for a pair ($948 on sale). The finish is nice enough. The cabinet feels quite heavy for its size and especially in the front...

www.audiosciencereview.com

SIERRA-1 V2 PAIR

Our World-Renowned Reference Monitor, Now Even Better! "Innovation, performance, intensive quality controls and environmental-friendliness all precisely balanced in a truly unique loudspeaker." Our new Sierra-1 V2 is a complete reimagining of our true classic, the Sierra-1. It fully represents...

www.ascendacoustics.com

Since you’ll have money left in your budget, buy a second KEF Kube 12b. Having two subwoofers makes sense for your large listening room.

 

[melomane13]

the Ascend Sierra-1 V2 are nice, but:
What motivates the Vincia is a lack of clarity in the fortissimo passages, so more emissive surface area is needed.
Since the woofer in the Ascend is identical to the one in the PMC, compared to the 7.5-inch woofer of the Buchardts,
which represents an emissive surface 2.25 times larger, the choice is obvious.