NAD C298 Class D power amplifier impressions

NAD C298 Class D power amplifier impressions

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NDA

22,185 posts

231 months

Friday 24th March 2023
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Harry Flashman said:
NDA said:
Hmmm, maybe one day. My speakers go down to 30Hz as they are, but I should try one at some point.
I've found it's a power thing. My speakers also go down to 30ahz, but bass takes a lot of power, so effectively outsourcing it to a separate amp has improved the volume and control a great deal.

Your speakers can control a KEF KC62 sub from the app. Time to go shopping!!
I nearly pushed the button last night - it was in the basket and everything. Hahahaha.

I have a cheap/rubbish Yamaha sub (NSSW050) which I didn't think added much to my Ruarks when I last used it. But it's not exactly representative of all subs.

My speakers have 8 of the identical drivers that are in the KC62's - so it's confusing me a bit as to why it would sound better. I sort of understand that it frees up the mid range a bit whilst wobbling windows, but I don't feel I'm lacking bass.

But I am on the cusp Harry.

RSTurboPaul

11,183 posts

264 months

Friday 24th March 2023
quotequote all
NDA said:
Harry Flashman said:
NDA said:
Hmmm, maybe one day. My speakers go down to 30Hz as they are, but I should try one at some point.
I've found it's a power thing. My speakers also go down to 30ahz, but bass takes a lot of power, so effectively outsourcing it to a separate amp has improved the volume and control a great deal.

Your speakers can control a KEF KC62 sub from the app. Time to go shopping!!
I nearly pushed the button last night - it was in the basket and everything. Hahahaha.

I have a cheap/rubbish Yamaha sub (NSSW050) which I didn't think added much to my Ruarks when I last used it. But it's not exactly representative of all subs.

My speakers have 8 of the identical drivers that are in the KC62's - so it's confusing me a bit as to why it would sound better. I sort of understand that it frees up the mid range a bit whilst wobbling windows, but I don't feel I'm lacking bass.

But I am on the cusp Harry.
Box volume/design will have an impact on bass output as well, of course, so it might be that the sub box is different to the Mains.

I get your query, though - I'd be asking the same.

Harry Flashman

Original Poster:

19,861 posts

248 months

Friday 24th March 2023
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So would I. But I think the range is the key here. Apparently the KC62 goes down to 17 Hz (according to What Hi-fi's tests, which is slightly mental, as my SVS only goes down to 23, and that feels deep).

The LS60 goes down to 26hz. My Sonus Fabers only get down to 32Hz, so your system will already do sub bass a lot better than mine - I needed a sub, you may not...

Try it, return if it isn't transformative!

NDA

22,185 posts

231 months

Friday 24th March 2023
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Nine extra hertz for £1,600. £177 per Hz. Bargain. smile

OutInTheShed

8,848 posts

32 months

Friday 24th March 2023
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NDA said:
Nine extra hertz for £1,600. £177 per Hz. Bargain. smile
Or about £2600 per octave?

Harry Flashman

Original Poster:

19,861 posts

248 months

Friday 24th March 2023
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Bargain.

legzr1

3,867 posts

145 months

Friday 24th March 2023
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The slight issue with reported lower frequency response of floorstanding speakers is the amplitude in relation to the rest of the frequency response - there are a lot of claims from manufacturers of ‘20Hz ‘ but at -6DB or even -10DB.

That’s where well designed and set-up subwoofers come in - 20Hz at 0DB is real sub bass and a world away from some of the crazy claims made by certain manufacturers.

For the record, I’m not saying the likes of SF or Kef are playing this game but it’s worth checking out not just the lower frequency response but also the amplitude level too - a cut of 3DB is technically half the volume.

Well designed subwoofers, well sited, can make use of huge amplifier power, long-throw drivers and digital EQ to boost at the lower levels to attain the sort of depth and sheer output that would put an average 8” bass driver through the wall if driven to similar levels.

Having said all that, and on a purely subjective basis - I prefer listening to 2-channel music without subwoofers for various reasons but there’s no denying the fun with multi-channel music or AV duties with a decent subwoofer doing its thing.
I’ve moved away from AV over the years using a simple sound bar for film duties but I’ve tried various subs from BK, Kef, Castle, B&W and ended up with a pair of SVS PC-13 ultras (madness, overkill and stomach churning).

I recently tried adding a pair of BK 12” sealed subs for stereo use just to fill in what I thought I was missing but ended up moving them on after a week of messing about with little (to me!) gain.

My point is, don’t automatically believe what manufacturers state in their sales literature but also don’t believe simply adding ‘whatever’ subwoofer will instantly transform the whole system - good subs can do this, poorly placed and spec’d subs will not.

If you install a sub, switch on and press play and are greeted with amazing sound then well done - if not, spend time setting up and placing.

I ran out of patience….


This pic shows one of the eight different placements I tried for the subs. Every new position required another coup,e of frequency sweeps using a DSpeaker antimode EQ device followed by a few tracks to listen to any improvements.

I will never get that week back but I’m pleased I tried it and can put it to bed (until the next monster is released by SVS with a 10KW amp and 20” driver in a cabinet the size of a Fiesta…)

To those of you trying (or thinking of trying) to add a sub - best of luck. I’ve heard some truly spellbinding systems using subwoofers over the years smile


Harry Flashman

Original Poster:

19,861 posts

248 months

Friday 24th March 2023
quotequote all
I have spent hours moving and setting this sub up and am finally there - seamless integration. But SVS' app helps with this enormously as you can tweak, and frankly mess with the sub on each track from the listening chair. For some music, I just have it switched off.

But I love electronic music, and on this, the sub has been transformative.

The best is that it isn't overpowering. It allows the rest of the system to do its thing.

paralla

3,819 posts

141 months

Friday 24th March 2023
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I'm envious of the level of spousal approval you've managed Harry.

When my other half and I moved in together my floor standing L+R, chunky center, big beautiful sub, dipole rear speakers were all vetoed along with a pair of bridged NAD C270's powering the L+R, a NAD C370 bridged powering the center leaving the AV Amp just doing the switching, processing and powering the dipole rears. I can't remember the model of the CD player and DVD player because they were functional, I didn't love them like I loved the power of all the amps.

I practically gave it all away on ebay.

We went to Sevenoaks to replace it with something a little more contemporary the sales guy asked what we wanted I said "the biggest baddest system you have" my husband said "the smallest, most discreet system you have" We met in the middle.


Harry Flashman

Original Poster:

19,861 posts

248 months

Friday 24th March 2023
quotequote all
I'd have never got away with that system!!

Basically, the beauty of the speakers has allowed me to get way with everything else...

Digger

15,105 posts

197 months

Friday 24th March 2023
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Does it still hold true that one method of discovering sub placement . . .

Place the sub at the listening position & then move around the room until you find where the bass sounds the best to your ears. Then plonk the sub down in that position & see what it sounds like from the listening position?

Harry Flashman

Original Poster:

19,861 posts

248 months

Friday 24th March 2023
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It's what I did!

AdamV12V

5,124 posts

183 months

Wednesday 5th April 2023
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Morning... New to the non auto marque sections of PH, albeit ive been a member for years and also very much into HiFi.

Id suggest maybe trying to reposition the speakers in your room as they should be more than capable of producing enough bass for anything other than the largest of rooms. Obviously I cant tell the size of your room from the pics, so apologies if you do indeed have a huge living room.

They look like you have them toe'd in heavily too, but again that could be the specific photos taken. The right positioning in a room can have a huge impact on how everything sounds and bass is one of the most easily impacted from poor placement.

Ive always found subs to be great for AV but pretty dire for proper hifi setups. Too hard to flawlessly integrate, you end up feeling the bass is detached (perhaps confirmatory bias), too rich or too light that you may as not bother. I have an old REL Q201E subwoofer which is capable of thumping bass and its lives its life as part of my AV system normally, where it performs brilliantly even set on a super low gain, but ive tried to integrate it into the hifi for parties and each time ended up disconnecting it for the above reasons.

Ive not heard the Cremona M's but I do own a Sonus Faber Omnia wireless speaker system which now lives in the master bedroom as a soundbar for its primary use. The sound is warm and the bass is rich, so if that's anything to go by in terms of house sound, Id be very surprised if the Cremona's sounded lean coloured.

Have a play around with position first I would say. Try putting them in an ideal setup even if it looks dreadful, then at least you will know what they are capable of in the room. Then move to a compromise position of sound vs aesthetics / practicality, as I do appreciate there is always a compromise to be had, especially when you have speakers as beautiful as Sonus Faber's!

Edited by AdamV12V on Wednesday 5th April 10:03

Harry Flashman

Original Poster:

19,861 posts

248 months

Wednesday 5th April 2023
quotequote all
Hi Adam, the toe in was for correct imaging at my listening point, but I have since toed them out a bit. No change to bass. That said, I will try anything possible that helpful folks advise!

Part of the reason for the sub is, being a living room, I have little choice over where they have to go, and even using DIRAC couldn't really give me the clean bass I desired. Sub was an easy fix. And, I'm a basshead smile

The sub is nice, but honestly, the amp, and subject of this thread, was the game changer.

RSTurboPaul

11,183 posts

264 months

Wednesday 5th April 2023
quotequote all
AdamV12V said:
Morning... New to the non auto marque sections of PH, albeit ive been a member for years and also very much into HiFi.

Id suggest maybe trying to reposition the speakers in your room as they should be more than capable of producing enough bass for anything other than the largest of rooms. Obviously I cant tell the size of your room from the pics, so apologies if you do indeed have a huge living room.

They look like you have them toe'd in heavily too, but again that could be the specific photos taken. The right positioning in a room can have a huge impact on how everything sounds and bass is one of the most easily impacted from poor placement.

Ive always found subs to be great for AV but pretty dire for proper hifi setups. Too hard to flawlessly integrate, you end up feeling the bass is detached (perhaps confirmatory bias), too rich or too light that you may as not bother. I have an old REL Q201E subwoofer which is capable of thumping bass and its lives its life as part of my AV system normally, where it performs brilliantly even set on a super low gain, but ive tried to integrate it into the hifi for parties and each time ended up disconnecting it for the above reasons.

Ive not heard the Cremona M's but I do own a Sonus Faber Omnia wireless speaker system which now lives in the master bedroom as a soundbar for its primary use. The sound is warm and the bass is rich, so if that's anything to go by in terms of house sound, Id be very surprised if the Cremona's sounded lean coloured.

Have a play around with position first I would say. Try putting them in an ideal setup even if it looks dreadful, then at least you will know what they are capable of in the room. Then move to a compromise position of sound vs aesthetics / practicality, as I do appreciate there is always a compromise to be had, especially when you have speakers as beautiful as Sonus Faber's!

Edited by AdamV12V on Wednesday 5th April 10:03
Is that not an issue more related to room nodes and (presumably) only having one sub so not being able to even out nulls and peaks across the space through multiple point-sources, rather than an issue with a sub itself?

Whereas AV is easy/ier to integrate well because the seat/s are generally only located in one location and the sub (and/or digital management) only has to be optimised for that one location?


The downstairs toilet is the place for monster bass hehe because the longer, bass wavelengths overlap/are reinforced below a higher frequency in the smaller room (AIUI) but there are obvious peaks and troughs in output as one walks through the house due to room nodes/wave cancellation lol

It does make me respect the work of those designing club systems, who can create even and powerful bass across a massive space!

AdamV12V

5,124 posts

183 months

Wednesday 5th April 2023
quotequote all
Harry Flashman said:
Hi Adam, the toe in was for correct imaging at my listening point, but I have since toed them out a bit. No change to bass. That said, I will try anything possible that helpful folks advise!

Part of the reason for the sub is, being a living room, I have little choice over where they have to go, and even using DIRAC couldn't really give me the clean bass I desired. Sub was an easy fix. And, I'm a basshead smile

The sub is nice, but honestly, the amp, and subject of this thread, was the game changer.
Try moving the speakers closer to the wall, with their backs onto a solid wall rather than a window. Even 1" movement can make quite a noticeable change in bass I've found, with the most noticeable changes occuring when getting within 4-12" of the wall. Again its about experimenting to work out what its capable of, even if the discovered perfect placement isn't then workable day to day.

Many speakers don't need to be toed in aggressively either, they will perform best with the backs perpendicular to the wall, but again experiment, find out what gives the best bass response and then toe in for improved soundstage if needed.

If every position fails to deliver on bass then it could be that your amp and speakers just aren't a good pairing. I know little first hand of your specific components, but for sure some brands work well together and others don't. Little help if the NAD is a recent happy purchase and you love the aesthetics of the speakers though I know...

AdamV12V

5,124 posts

183 months

Wednesday 5th April 2023
quotequote all
OK, So I've had a google of the spec of the speakers and amp. Your speakers are 4ohm impedance, which means they will be challenging to drive for any amp. Being honest I suspect your amp in stereo mode will not have the power to grip them properly, which would could easily result in a lack of bass slam.

Appreciate you've only just bought the amp, and it was a considerable step up from where you were, but it may be that you need to try mono blocking it and buying a 2nd one, to really drive those speakers to get the best out of them. Perhaps the HiFi shop where you bought it would be willing to loan you another to test?

Mono-blocking two of those NAD C298's would give another really big step up, and likely be enough to drive those 4ohm speakers properly, whilst capitalising on your existing investment too!

paralla

3,819 posts

141 months

Wednesday 5th April 2023
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The C298 is rated at 340W x 2 into 4 Ohms (Stereo mode, ref. 20 Hz-20 kHz at rated THD, both channels driven) so is not short of power .

SF recommends 50 - 300W for the Cremona's.

Having said that I'm a big fan of bridging, adding another (£1700ish) amp and running them as mono-blocks certainly won't hurt the bass.

More Powahaaa. You know you want to.......

AdamV12V

5,124 posts

183 months

Wednesday 5th April 2023
quotequote all
paralla said:
The C298 is rated at 340W x 2 into 4 Ohms (Stereo mode, ref. 20 Hz-20 kHz at rated THD, both channels driven) so is not short of power .

SF recommends 50 - 300W for the Cremona's.

Having said that I'm a big fan of bridging, adding another (£1700ish) amp and running them as mono-blocks certainly won't hurt the bass.

More Powahaaa. You know you want to.......
Indeed, its not short of power, but having read quite a few reviews of the Cremona M's they seem to be power hungry even for a 4ohm speaker.

They are also knocking on for £10k a pair new, and there's an old rule of spending a similar amount on your speakers as your amps to get the most out of them... I know that's a very rough rule, but easy to get out of sync if you buy speakers 2nd hand for a snip, then buy your amp new for similar money.

I run a pair of Monitor Audio Platinum PL200's which are also 4ohm, and rated as needing 100-250w to drive them. They are also power hungry. Initially I drove them with a single Cyrus X-Power in stereo mode and it simply didn't have the oomph to make the bass rock and led to disappointment and left me seeking more.

I then upgraded and now drive them very successfully with a pair of Cyrus X300 Anniversary mono block amps, and the bass is now tight and huge. You can actually feel as much as you can hear it, and more than once friends visting have commented on being able to feel the bass in the pit of their stomach even at just reasonable listening volume. Living room is 700 sq ft in area.

I appreciate the C298 is more powerful than the X-Power was, but then the Cremona's need more power than my PL200's do also, so likely similar situation, especially as both are 4ohm speakers. The move to bridged mono blocks was very significant, indeed so much so that I have never felt the urge to upgrade anything since on the main room hifi!

Flying machine

1,132 posts

182 months

Wednesday 5th April 2023
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Like Harry I also think that SF produce some great looking speakers and I have to admit that it was a big influence on speaker choice - I've got a pair of Serfino Tradition floorstanders in my HiFi, complemented by a pair of subs (Rel T9i's).

I completely agree with everything that's been said regarding the benefits of more power delivered by the amps - more watts is certainly better, but also the current delivery available. I recently moved from a Gryphon Diablo 300 (a superb integrated amp IMO) to Gryphon Essence pre and power amps, and despite their comparative rated outputs it was a marked improvement IMO, particularly the bass volume and control, to the extent that I'm wondering if I still even need the subs. As Adam and Paralla have suggested, either try a different, higher rated, power amp or a pair of monoblocks