Quantcast

power amp on a budget?

Kitchen Knife Forums

Help Support Kitchen Knife Forums:

MarcelNL

Senior Member
Joined
Feb 9, 2018
Messages
327
Reaction score
249
Inferno, You seem quite happy playing with your synth,,, so why not approach your end-goal in steps? Work on a mono set-up for the synth for now,,,, get your amp fixed, install a quieter fan.and stay away from 2-ohm operation. If you did that, your new fan would probably rarely need to kick in. There's no point in going stereo on the synth. You'll reduce costs for now, and you can add on later. And,,,, stay away from running that Behringer in bridge mode. Get a more efficient speaker if you need the volume.

P.S. I admire your tenacity. :cheers:
That is some solid advice if you ask me, and on two accounts; first -stay away from that Behringer in bridged mode, it likely killed your previous speakers due to clipping and is likley to do so again (the power rating is inflated through the roof IMO) and secondly; look for high efficiency speakers with more surface area if you need more SPL.
 

Bobby2shots

Well-Known Member
Joined
May 8, 2019
Messages
175
Reaction score
93
Location
Lachute Quebec
That is some solid advice if you ask me, and on two accounts; first -stay away from that Behringer in bridged mode, it likely killed your previous speakers due to clipping and is likley to do so again (the power rating is inflated through the roof IMO) and secondly; look for high efficiency speakers with more surface area if you need more SPL.
Thanks MarcelNL,

I should have added that doubling the amp output, only gives you a theoretical 3dB gain,,, barely perceptible,, minus the thermal losses, and we've all seen how that's worked out so far. A more efficient speaker is definitely in order here.
 

Bobby2shots

Well-Known Member
Joined
May 8, 2019
Messages
175
Reaction score
93
Location
Lachute Quebec
This is what I did... 120Hz.

Let your ears be the best guide there. Fine-tune to see what sounds best. With small monitors, you could try up to 160 HZ if need be. A lot could depend on the resonance of your monitor cabinets.


Clearly at the higher frequencies >80Hz directionality starts to come into play. I'd say below that, phase gives more of a concert hall effect? I dunno... like I say, its not that I can hear where it is. But as opposed to one, I felt the room some how sounded larger. Again... could be psychological
When you run a single sub,,, or even two subs tightly clustered, you get an effect called acoustic-coupling, with an overall 3dB gain,,,,, AND, you eliminate phase-cancellation. When you separate the subs, you start to raise the spectre of phase cancellation. Certain frequencies (depending on wavelength), will drop out, or increase, as you walk around the room.


Whilst not tiny, mine are two-way and only have 5" woofers - so crossing over high seemed to be sensible.
It can be,,,, each case is individual. A lot depends on the rigidity of the mains, (cabinet resonance).
 

inferno

Senior Member
Joined
Jan 11, 2018
Messages
2,644
Reaction score
1,172
Thanks MarcelNL,

I should have added that doubling the amp output, only gives you a theoretical 3dB gain,,, barely perceptible,, minus the thermal losses, and we've all seen how that's worked out so far. A more efficient speaker is definitely in order here.
while the high efficiency speaker might be nice. its also occupies more than 3 times the volume than the one i built. this is how it works. its is efficient because it uses a very big enclosure.

the one i built is actually high efficiency if you compare it pretty much all home/studio subs.
just look at this one KH 870 G
its a 4000€ sub! mine was very cost efficient compared to this one too.

Maximum SPL at 1m (Red: 3% THD, Blue: 1% THD)

 

Bobby2shots

Well-Known Member
Joined
May 8, 2019
Messages
175
Reaction score
93
Location
Lachute Quebec
while the high efficiency speaker might be nice. its also occupies more than 3 times the volume than the one i built. this is how it works. its is efficient because it uses a very big enclosure.

the one i built is actually high efficiency if you compare it pretty much all home/studio subs.
just look at this one KH 870 G
its a 4000€ sub! mine was very cost efficient compared to this one too.

Maximum SPL at 1m (Red: 3% THD, Blue: 1% THD)

Inferno, I have no doubt that the 4000€ KH 870 G is a fine sub, for what it is, but at a max spl of 118dB, it's not exactly going to "rock the house". That particul speaker should really shine in frequency-response however. Pretty well anything that K&H produces, are exceptional in performance.

I would think that the K&H 870 G would probably find a happy home in a studio environment, but not necessarily in a very large studio. Don't forget those measurements are "Max SPL @ 1m. At a greater distance, the inverse-square law will reduce output by half at every doubling of distance. With MAX SPL at 113dB@1m, this becomes 110dB@2m, and 107dB@4m, and 104dB@8m, and 101dB@16m, and so on.

For comparison sake, my Yorkville LS801P is 1500w , 2500w peak, has a sensitivity of 105dB at 1w/1m with 134dB continuous/140dB Max measured at 1m in half-space. That said, I wouldn't be surprised if the K&H 870 G sounded better (tighter/cleaner) at rated output. The Yorkie however. would blow it away in total output-level. A lot would depend on the room.
 

Bobby2shots

Well-Known Member
Joined
May 8, 2019
Messages
175
Reaction score
93
Location
Lachute Quebec
Dimensions (DWH xbackW, inches)23 x 27.5 x 32
Dimensions (DWH xbackW, cm)58.4 x 70 x 81.3
Weight (lbs/kg)



The cabinet is very heavily braced 11-ply 5/8" Russian Birch plywood.
The 18" driver is by B+C,,,, but, Yorkie at one point was going with a similarly spec'd in-house design. B&C have a LOT of models, and they provide bass-drivers for MANY companies. Very highly regarded in the industry.

The Yorkie is a rear-horn loaded design. The cabinet is also a tilt-back design with casters.
137.3 / 62.3
 
Last edited:

MarcelNL

Senior Member
Joined
Feb 9, 2018
Messages
327
Reaction score
249
think big inferno, big sound needs big speakers...Horns, open baffles it's all too large for comfort, yet too good to live without.
I integrated the open baffles in a wall, it does not get more infinite for a baffle, you can build corner horns but for low frequency they still end up being large...
 

Lars

Founding Member
Joined
Mar 9, 2011
Messages
1,077
Reaction score
2,618
Location
Denmark
I liked the K&H O300D. Pretty workable nearfield.
 

Bobby2shots

Well-Known Member
Joined
May 8, 2019
Messages
175
Reaction score
93
Location
Lachute Quebec
I liked the K&H O300D. Pretty workable nearfield.
Yep,,, it's an INCREDIBLE monitor. One of the best I've ever heard. Crazy expensive, but what a sound. The resolution is uncanny. Imaging is virtually holographic. Mated to it's matching sub, you simply would not want "better",,, nor would I think it exists.
 

Lars

Founding Member
Joined
Mar 9, 2011
Messages
1,077
Reaction score
2,618
Location
Denmark
Yeah, I didn’t really like the sub. And they were a littte too hyped for me but still workable
 

Bobby2shots

Well-Known Member
Joined
May 8, 2019
Messages
175
Reaction score
93
Location
Lachute Quebec
Yeah, I didn’t really like the sub. And they were a littte too hyped for me but still workable
You really have to be conservative with the subs,,,, you don't want those low frequencies colouring the highs. Just bring up the sub's output level very gradually, until you get a natural-sounding blend. Nothing sounds worse than a disproportionate blend of highs vs lows. BooMMM,,,BooMMM,,,BooMMMMM. A lot of folks just go too crazy when apllying subs, and it sounds like crap. It's got to be "natural",,,, not hyped.
 

Lars

Founding Member
Joined
Mar 9, 2011
Messages
1,077
Reaction score
2,618
Location
Denmark
I could do a session on them without subs, but they are still not my first pick.
 

Bobby2shots

Well-Known Member
Joined
May 8, 2019
Messages
175
Reaction score
93
Location
Lachute Quebec
I could do a session on them without subs, but they are still not my first pick.
Maybe so,,, depends what you're playing in that session. In a full-range application, you could be missing out on an entire octave of low-end frequency response. A synth for example, is capable of very deeeep lows.
 

Lars

Founding Member
Joined
Mar 9, 2011
Messages
1,077
Reaction score
2,618
Location
Denmark
Maybe so,,, depends what you're playing in that session. In a full-range application, you could be missing out on an entire octave of low-end frequency response. A synth for example, is capable of very deeeep lows.
Nah..
 

inferno

Senior Member
Joined
Jan 11, 2018
Messages
2,644
Reaction score
1,172
Maybe so,,, depends what you're playing in that session. In a full-range application, you could be missing out on an entire octave of low-end frequency response. A synth for example, is capable of very deeeep lows.
everything sounds good on small monitors. and its really not until you add a sub you notice what you have missed all that time. i can hear the bass on the jbls when i run them full range but i can't really feel it.
 

Bobby2shots

Well-Known Member
Joined
May 8, 2019
Messages
175
Reaction score
93
Location
Lachute Quebec
Inferno, don't forget the smaller Yorkies I mentioned earlier. (Yorkville NX720P). Much smaller than my LS801P, and excellent output. Here's a link to a few more by TurboSound and ElectroVoice.

 

Lars

Founding Member
Joined
Mar 9, 2011
Messages
1,077
Reaction score
2,618
Location
Denmark
have you heard any dynaudio active monitor? are they good?
Have used the Air-6 near fields for some sessions and they are great. Have also used some of their passive stuff, the M-1 mains and BM-15 midfields. Really like them.
 

MarcelNL

Senior Member
Joined
Feb 9, 2018
Messages
327
Reaction score
249
Dynaudio makes great stuff, so does Scan Speak, DIY-ing near field monitors is very doable if you like to tinker, still costly but you end up with pretty much double the sound quality when compared to buying off the shelf.

Used to play with a Podszus-Görlich- Scan Speak modded esotar combo until I went for full range, now using 4 13" Klangfilm era speakers as 'near field monitor'.

BTW; for the 'high starts at 300Hz' club; try Mika Vainio (or here with Pan Sonic);
 

gregfisk

Well-Known Member
Joined
Mar 9, 2020
Messages
216
Reaction score
146
Location
Seattle
This is what I did... 120Hz.




Clearly at the higher frequencies >80Hz directionality starts to come into play. I'd say below that, phase gives more of a concert hall effect? I dunno... like I say, its not that I can hear where it is. But as opposed to one, I felt the room some how sounded larger. Again... could be psychological



I guess this is one of the benefits of multiple subs. If not stereo subs, dual-subs can help lower distortion in the sub-bass. Each would be driving half as hard. With stereo-subs, when you cross-over high you are offloading bass from the woofers to the subwoofers. The woofers wont have to move as much and will have lower distortion. Probably not so necessary when you have a large mains. Whilst not tiny, mine are two-way and only have 5" woofers - so crossing over high seemed to be sensible.








I almost entirely agree. It was a lot of fun using the minDAC and REW to apply the active crosser and room treatment. Seeing the frequency response on the screen, mucking around with the filters and listening to music allowed me to fairly quickly correlate what I was hearing with something quantifiable and visual. I played around for a bit for fun and then tried to get the response response as flat as I could. From there I tweak equaliser settings to my taste.

But yeah... you aught to be moving towards something your ears enjoy!
IMO the one thing that people don’t spend enough time on is room treatment. You can measure your speakers all day long and I commend you for that but if you don’t have good room treatment it’s not going to matter when you turn that music up loud.

I personally use servo controlled woofers. My speakers have two 12” servo subs each. I can’t recommend them enough if you like clean bass. No more muddy bass since they start and stop instantly. I also have a lot of room treatments so that the bass doesn’t bounce all over the room.
 

gregfisk

Well-Known Member
Joined
Mar 9, 2020
Messages
216
Reaction score
146
Location
Seattle
think big inferno, big sound needs big speakers...Horns, open baffles it's all too large for comfort, yet too good to live without.
I integrated the open baffles in a wall, it does not get more infinite for a baffle, you can build corner horns but for low frequency they still end up being large...
My speakers are open baffle and I really like how they interact in my room. They aren’t huge but with two 12” servo subs per speaker they aren’t small either.
 

inferno

Senior Member
Joined
Jan 11, 2018
Messages
2,644
Reaction score
1,172
Have used the Air-6 near fields for some sessions and they are great. Have also used some of their passive stuff, the M-1 mains and BM-15 midfields. Really like them.
what about these? the bm5 mk3 is 800€ a pair and the bm6a is twice the price.
the cheap one has 100w class d and the other one 200w a/b.

 

Lars

Founding Member
Joined
Mar 9, 2011
Messages
1,077
Reaction score
2,618
Location
Denmark
what about these? the bm5 mk3 is 800€ a pair and the bm6a is twice the price.
the cheap one has 100w class d and the other one 200w a/b.

Never heard either of those.
 
Last edited:

Bobby2shots

Well-Known Member
Joined
May 8, 2019
Messages
175
Reaction score
93
Location
Lachute Quebec
Here's a sub for you;

 

inferno

Senior Member
Joined
Jan 11, 2018
Messages
2,644
Reaction score
1,172
bobby for me i feel the 116 or so spl i have (corr: had) is good. this is basically as loud i want or need to play. and the problem i have now is that to get that spl back i need to spend way more than 200€. the behringer amp was 180€ when i bought it like 10 years ago. and its a carbon copy of the qsc 1450 i think. an 800€ amp. no nonsense "no audiophile" construction too. just clean(ish) power.

i have 2 more unused subwoofers though. should i want to increase my spl by 3dB.

i think the real problem when the behringer worked was that the jbls were simply too weak. and not only that the pwm amps in them did not make the speakers sound better the louder it got. it just got louder.

i think of it like a digital picture. its a good comparison i think. with an a/b amp the more you turn up the vol the finer and finer (more and more of them) the pixels get. but with the jbls you have like this fixed rez, and when you get to a certain magnification the pixels just get bigger. and the sound dont get "better", yeah thats what i'm hearing.

i have never ever heard this with any a/b amp so i guess this is a characterisic of a class d amp (a cheap one at least). i mean the jbls sounds linear enough and (almost) loud enough but that loudness does not correspond to increased "goodness" somehow.
 

inferno

Senior Member
Joined
Jan 11, 2018
Messages
2,644
Reaction score
1,172
btw what i'm thinking about now is simply getting a new qsc 1450 (800€) and simply mount a very big black alu heatsink to the stock one. my brother thinks this a good solution too. and he built one of the first fully passively cooled computers in the world so he knows a good deal about passive cooling.

why black?? thats why Kirchhoff's law of thermal radiation - Wikipedia

and then for monitors i'm thinking about either getting the dynaudio i posted above the 6whatever model (1600€) or the k&h 5 incher. but i think the k&h will not in reality be able to play louder than the jbls i already have. because there is no free lunch with physics. so a 5 incher is a 5 incher. and 40w is 40w. and 10w extra will not make it louder, neither will 1 or 2 liters extra box size. but a 7 incher, yeah thats 3dB across the board. and 100w instead of 50w is 3dB extra right there across the board. i have simulted maybe 30-40 5-7 inchers (seas/scanspeak/morel etc etc). and there is simply no free lunch. and if there is i have not found it. the only free lunch there is, is that woofers designed for bigger boxes will play louder. and that not really a free lunch.

and you cant really take a short cut like my subwoofers do by simply increasing xmax by 100% or so. since these smaller woofers still need to play 3khz or so. and they need to have a certain dispersion sideways that matches the tweeter at crossover. and you simply need bigger voice coils for that, with more thermal mass, and then they simply wont have good dispersion at 2-3khz.
 
Top