Mac amp of course.
Underpowered?
Hi guys. Newbie here asking for advice.
I recently purchased a pair of B&W 702 Signature (8Ω, 30-300W, 90 dB) to replace my old faithful 683s (8Ω, 20-200W, 90 dB). I am running them with a McIntosh MA252 (100W into 8Ω, 160W into 4Ω). I purchased them thinking they would complete my end-game system. However, my excitement turned into disappointment when I realized the lows were somewhat lacking. For all their faults, the 683s had a great dynamic low kick (no sub) that I was looking to take one step further. Unsurprisingly, the highs and mids on the 702s were indeed more detailed and separation was clearer, but I couldn't get over the uninspiring lows. I found myself listening at higher volumes chasing for that bass oomph. Neither playing with the EQ at the source nor the amp was satisfactory. So, I did the research that perhaps I should've done before purchasing the 702s and found out they are quite power hungry despite the specs being similar to the 683s. I emailed B&W and McIntosh and they agreed the amp is probably underpowered for the 702s. B&W described the sound of an underpowered speaker as one lacking low response and details, which is spot on. McIntosh suggested the MA352 (200W into 8Ω, 320W into 4Ω).
Of note, I love the MA252 and really wish there was a way to make this work. I don't need a DAC/streamer/etc so I'm happy to put all my money on better sound vs tech features. But I also think the speakers sound amazing even when somewhat underpowered and I'm considering upgrading to a MA352, Michi X3, Hegel 390. Another option could be to get a sub? But I feel that would defeat the purpose of having a 3way standing speaker and then I might as well get a pair of bookshelf speakers (805 D4s, LS50 metas?).
So what do you guys think? Is it normal for a speaker that's rated 30-300W to be underpowered with a 100W amp?? What would you do:
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Sell the 702s and look for a better match for my MA252?
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Upgrade the MA252 (MA352? Michi X3? NAD 33?)?
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Get a subwoofer?
I would really appreciate your thoughts/advice!
90 responses Add your response
I would guess buying a new amp will not work, you are chasing a ghost. The speakers have no low bass, look at the stereophile measurements below. I owned the 703S awhile back and ran it off a vintage (1976) 40 watt Marantz and it was fine. I would add subs with a highpass or buy a more well rounded speaker. I run much larger speakers than the 702s2 and still run duel subs. Subs done right are always better than no subs. Even wilson audio makes giant subs with external crossovers for their giant speakers. There is a reason, it is alway better with subs. |
Wow, many thanks to everyone who shared their opinions and experiences! It's so great to be part of this community and I only hope others also benefit from this post.
Another aspect of this is that the issue doesn't resolve with high volume, which yes, comes with a better bass response but at levels where the highs are too piercing and fatiguing. The amp and speakers ARE capable of getting to good bass levels, but not in balance with the rest of the frequencies. That to me suggests the amp is underpowered since I doubt the speakers were made to be this skewed.
Thanks again to everyone!
Daniel |
100 watts is plenty...BUT: I think you need an amp that doubles down on the power with halving of the impedance. Or at least close to doubling. Some amps will deliver 100 watts at 8ohms and 200 watts at 4 ohms and are stable down to 1 ohm. An amp like that will not waiver with a big impedance dip. You can also go further up the McIntosh line to amps with autoformers. Monoblocks would help too.
And yes, I would also look at speaker placement.
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The upgrade to MA352 will provide a modest improvement in SQ based on power, but dialing up the low bass EQ is a targeted solution for the better damped woofer alignment in the 702 Sigs vs. your old under damped 683s. Adding a REL sub instead of the amp upgrade is too, and depending on which model and what deal you can get on the Mac, may not be as costly. If your room permits various subwoofer placements that approach has the advantage of letting you optimize speaker placement for overall imaging, and sub placement for bass loading. The spot where the speakers deliver better bass may not correspond to where they image best. |
I ran into a very similar thing but I knew that lack of power had nothing to disclose with it. Started out with what turned out to be an amazing thing I bought a pair of furutech wall outlet plugs all of a sudden I had some base out of my Levinson 33s. I then put a set of furutech plugs on the end of the captive power cords better again. Then I fooled around with room placement. Each time I got more base. Also thinking of you have two sets of binding post on the back of the speaker's it is time to replace the flat tin jumper bars and go to a true jumper. Easy to get that before you buy just try it with some copper wire of a heavy gauge of you think it does a bunch then get a good one. Also I bought a cable break-in ma home that was made by siltech that made a huge difference on every piece of wire on the system. The tonal range got bigger at bother ends. It didn't matter if the wire had been used regularly for twenty years. The range got bigger the sound fuller etc. When you setup the room I personally like the speakers setup on odds vs evens. On evens you tend to accentuate mid bass. A real rock and roll set up the speakers a quarter of the way into the room and a sixth of the way from the side of the room and the chair a quarter of the way into the room from the back wall. Personally I set the speakers a their of the way onto the room and a fifth for the side walls. I Then.make fine adjustment from either one of those places. Make sure the speaker s are level to each other and they are at the exact same height. Do you have spikes down to the floor? Did you change any placement of the gear? Different stands can make a huge difference as well. Personally I think your base is there you just have to find it.
Regards |
The first thing to do is if you have standard wires, you will need a jumper if there is 4 posts and you have 2 wires to connect( plus and minus) Second, play some music walk around the room. Do you hear boomy bass in some places and none in others. Go to the corners, is it boomy there? If you hear this then you should try moving your speakers around. I point them right at me and sit back the same distance as the speakers sit apart. Some speakers only need to be tilted in slightly. Third, even if the room is not too bad for acoustics, a sub is a real helper here. Very few speakers go down low enough in the bass. Especially, since you said you liked bass. But you may find once you fix positioning and room problems your speakers are OK. Try sitting a sub right beside a speaker. Point it toward you or the wall. If you have a second sub put it along the wall by you. Fourth, you are used to the B&W sound so I would not ditch these speakers...yet. Same with the amp. Depends on how loud you like your music. But amp replacement is after you try a sub. A powered sub has it's own amp and bass takes the most power, so your 252 may be enough. Also, less excusion of the woofers reduces distortion of midrange frequencies. Don't feel bad, they always say build your system around your speakers. :)
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@dridel Congratulations on your new speakers!
I grappled with a similar problem over the past three years. Having moved to a new house my B&W801M S2s didn't sound the way they used to. I upgraded the XOs, then the preamp. Had my Krell KSA-250 recapped. All to no avail: the bottom octave was still AWOL. Then I had a lightbulb moment: maybe the problem was the room. I lugged one of my BK subs downstairs and hooked it up. Result! The bass was back.
Ordered two new subs and dialled them in. Now the system sounds better than it ever has.
I reckon your room doesn't play nice with the new 702s. They aren't speakers that are hugely difficult to drive, I don't think your MA252 is the problem and a new amp is not going to fix things. If changing the 702s' room placement doesn't improve their bass response and apart from that you like they way they sound, the quickest, easiest, and most satisfying way to address that issue would be to install two subs. Been there, done that...
REL (and BK) subs feature a high level connection which I prefer for a two channel connection. You do not hear my subs, you only feel their "foundation", along with a wider, deeper sound stage. A friend who popped in for a listen didn't even notice them sitting in the background as the music was playing...
Good luck! |
Before you change equipment I too strongly recommend playing with speaker placement AND listening position. I too had this exact same issue when I got my floorstanders (Spendor D7.2) and thought a sub could fix it, it didn’t sound ‘better’, I could just hear an exaggerated boomy bass that was separate to the speakers. So I spent hours moving the speakers around and at the same time moving my listening position around. What you might have is a null where you are sat which is cancelling out the bass. If you find standing in different places gives you more bass, then there is bass in your setup, you just need to find the listening position coupled with speaker placement that is the bass sweet spot. I have the Hegel H390 and personally love it, the bass it produces has a wonderful tone that is addictive. I am not suggesting it is THE amp or that it will improve things, just that I’m a happy owner of one of the amps you mentioned. Room treatments will help the bass response further but just make sure if you are going to use them you get something that will actually make a difference. For the lower frequencies it is all about the depth of the trap, thin traps will do nothing to slow down the lower frequency waves which can be cancelling each other out. Finally once I had found my preferred speaker and listening position, I purchased a basic app called HouseCurve and that was a super cheap way to get some feedback on the in room frequency response. This app is in no way professional like REW, however it did give me the frequency ranges that I had bass dip in which I then boosted with parametric EQ and reduced slightly the upper frequency peaks. Together that massively balanced out the sound bringing the bass through even more. If the highs are dominant you’ll notice them more and reducing them slightly can bring through more bass perception. My big takeaway is there is a lot you can do, which really is the fun of owning a system, the tweaking and trialing things. Simply replacing the amp may not bring any improvements if it’s actually the room and placement of speakers and seat that are the issue. Try all of the above first and if there are no improvements then you may need to upgrade. I’m from the UK and we tend to try and not run subs, your floorstanders will have enough bass and it is better (imo) to get it out of them rather than just over-boosting the bass with subs that aren’t integrated properly. I now don’t use a sub for music as my setup has it all following the work I carried out above, the sub only gets turned on for films and at this point only provides rumble. |
That plot labeled “graph 5” in the link looks like -5dB at 100Hz... and headed south.
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Reading all this discussion makes it all the more clear that the gear is as much an instrument in the music you listen to at home as anything that's recorded on a given disc. Talk about transparency or neutrality or specifications is kind of bunk. A stereo is a machine that makes the music sound better. |
can't believe it's not enough power unless you're in a monster size room. Systems have oomph if they're dynamically linear and that can be limited by a speaker with a lousy impedance load and/or an amp that can't handle the load. My gut feeling is it's the speakers. A common recommendation for non-dynamic speakers is to add power and play loud. This doesn't really provide linear dynamic level changes but loudness compensates some for a lack of life in reproduction. |
#1 - do you like the speakers? #2 - Those Purifi Eigentakt do not look as good as a Mac. But they likely have the cojones. As @ctsooner mentioned there is the Vandy sub, which is sort of an active alternative to the DSP based approach. And that folds back into #2 as some load is relieved off of the speakers and amp.
I know nothing about the B&W, but are you smitten with them? They do appear top be a bit weak on the lower registers:
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Make sure you run them for at least 200-300h at regular listening volume (65-80 dbC) for full break-in before making any final conclusion... May not be a problem of amp power at all. Also, if you are not bi-wiring them, at least use good bi-wiring cables with similar quality to your speaker cables, not the standarf jumpers provided. Hope this helps. |
@jjss49 I agree 100% on your statement regarding satellites v floorstanders. The bookshelves just don't move enough air in my room. |
You have fantastic speakers in the 702 Sigs. Yes, they need more power. I never heard everything my 683 S2s could do until I got a Rotel RB-1590 350 watt amplifier with a huge power supply to drive them. In a small room with a lot of boundary reinforcement the MA252 would probably be adequate but it still wouldn’t handle the three woofers well on the 702 Sigs. Good luck with your decision. Don’t give up on the 702 Sigs to quick, they are amazing. Cheers, Scott |
+1 work on speaker placement if not +1 add two sub woofers… always add pairs… they will also extend soundstage as well as bass. Most recommended brand is REL. I am also not a Mac fan, but it should have enough power… maybe Bo up a level in speakers, B&W is not know to lack bass and a frequently paired with MAc. |
Dang, you got yourself in a tricky situation. There is no easy way out. I'm not a big McIntosh fan but the MA252 is a neat unit and 100wpc is enough if you are not trying to wake the neighbors. Perhaps some Triangle Delta loudspeakers (or other easy to drive loudspeaker). not a huge step up in efficiency but they will sound good at lower volumes, but you still might need a sub. |
op - a few thoughts 1. speaker placement and room loading is key to getting good bass response, try that in all reasonable permutations before changing equipment 2. treble and midrange clarity will always seem enhanced when there is less bass foundation (or bass boom)... those things are highly interrelated... trick is to have cake and eat it too 3. subs can certainly help (a pair ideally), rel’s are very good, others are good too - but note point #5 below 4. the mac 252 should have ample power and grip to drive the b&w’s -- you can try a different amp (a hegel is what i would try if you go that route after doing point #1), but i suspect things won’t change too much 5. there is a recent thread on big vs small (satellite type) speakers... that may be a good read for you... bottom line is big speakers sound bigger, it is not just the deep bass, it is how air is moved, and midrange and midbass is presented in a much more easeful, enveloping, full, rich way... that is the difference good luck |
I have some friends who use the new Vandersteen Sub 3 over their previous REL in that situation since they design them to keep the sound of the main amps so you can tell where they cross over , plus that takes the load under 120hz away from the main amp and speakers. Speakers and a,ps get the advantage here. They are also fully adjustable for the room with a built in 11 band EQ. Just a thought. Designs change and maybe the newer speakers just don’t kick like the older ones. No idea there. Good luck |
Actually I just thought of a combination for you to try. Plug the ports and move the speakers closer to the wall. Plugging the port will damp the peak at 100 Hz but more importantly slow down how fast it rolls off below that. If they still sound anemic, you definitely need a higher current amp (not necessarily more watts, more watts in the bass). If they suddenly improve, but you still want more bass a sub is a good option. |
I just looked at the specs. There's a combination of fast roll off below 100 Hz (pretty high for a floor stander!) and an impedance dip there at the low end. I'd strongly suggest you measure your room before making any adjustments, but I would not be surprised if you are a very good candidate for a sub. You'll want something with some built in DSP capabilities to help you manage room modes, and, as always, consider room treatment before you do anything else. |
