Questions about amp/monitor pairings.

Quilope

Quilope

Enthusiast
First I would like to say how happy I am to have discovered this forum/website a few days ago - what an excellent resource!

I have been trying to learn as much as I can about this before posting, but my head is spinning - I have a lot of questions. I'm sure you can tell from the section in the forum that I am new, so please be patient. Tax return time = a little extra money to spend on sonic toys.

At first I thought the Tannoy 601P's looked good, but after discovering this place it looks like Behringer B2030P's look like a great bang-for-the-buck monitor + some pre-existing DIY posts on how to upgrade them! It seems WmAx's views are somewhat controversial, but ultimately solid. I read through this thread and heard what everyone had to say about how a pair of B2030P's + 1 or 2 Dayton 8" powered subs is a nice noob setup.

Next, I am looking at cheap amps and the t-amps seem attractive to me (largely because they seem affordable). It seems as though some are convinced the 2020 chip is the best, but those seem underpowered to me. Like the Topping TP20 MK II.

According to specs it's Output Power 2 x 20W @ 4ohm, 2 x 12W @ 8ohm, so... too underpowered?

So I am also looking at the next two;

Dayton Audio DTA-100a Class-T Digital Amplifier 50 WPC

which is 50 watts per channel @ 8 ohms (still underpowered)

and

Dayton Audio APA150 150W Power Amplifier

which is 150 watts total, but only 8 ohms when it's bridged mono. So, according to on-paper numbers, I'd have to have one of these for each B2030P.


Also, the specs for B2030P's say they want 100 watts each, but in the B2030P user manual, it says they want 200 watts apiece. Page 6, paragraph 3:

"3.1.2 Amp - The power rating of the amp you use should be roughly twice the load capacity of your TRUTH. Consequently, the B2030P should be operated with an amp with a load capacity of 2 X 200 Watts, and the B2031P with an amp with a load capacity of 2 X 300 Watts."

This is all very confusing to me...

So, assuming I get a pair of B2030P's and an amp, is the Dayton Audio SUB-80 the hardware being referred to?

Also, what else would I need to purchase to get all this going? Is 10 AWG Dayton speaker wire good?

Side note: this all started because I thought ZVex's ImpAmp and Decware's Zen Triode looked cool :confused:

Any input would be greatly appreciated!!
Thank you.
 
jp_over

jp_over

Full Audioholic
I can assist with some of your questions.

I run the 2030P as desktop speakers with my PC (unmodified). If you cross them over to a sub you likely won't even hear the port noise (I play mine full range and I don't notice it.). Of course, the bass response is limited but I’m ok with this since this setup is temporary.

A solid 50 watts per channel is more than enough for near field listening. I think my receiver is around 90 watts per channel and it plays much louder than I'd like to listen to. 150 watts per channel for the B2030p is too much for near field listening in my humble opinion.

16 gauge wire is plenty; 10 gauge is really not necessary and certainly costs more. Take a look at monoprice.com. Many of the members here use them (myself included).

You mentioned:

"Also, the specs for B2030P's say they want 100 watts each, but in the B2030P user manual, it says they want 200 watts apiece. Page 6, paragraph 3:

"3.1.2 Amp - The power rating of the amp you use should be roughly twice the load capacity of your TRUTH. Consequently, the B2030P should be operated with an amp with a load capacity of 2 X 200 Watts, and the B2031P with an amp with a load capacity of 2 X 300 Watts.""

If you are comparing the 2030P with the 2031P, the 2031P is a 4 ohm speaker which means your amp/source needs to be capable of handling a 4 ohm load (the 2030p is an 8 ohm speaker). Most of your major brand receivers (Yamaha and Onkyo) are fine with a 4 ohm speaker. Again, a solid 50 watts per channel will be fine depending on your listening levels. If you are not using these for near field/desktop listening, I'd go with 100 watts per channel from a decent amp or receiver.
 
Quilope

Quilope

Enthusiast
jp_over,

Thank you so much for your advice! As I am VERY new to all this, your answers raised a few more questions, though...
...and here they are; "port noise." Is this just the sound of air being sucked back and forth through the ports? Why are speakers built with ports if they sound bad?

What does it mean to "cross something over?" When you saying "playing them full range," does this mean you're not cutting out lower frequencies that would otherwise be diverted to a subwoofer?

What defines "near field listening?" I plan on using this setup for production and general listening with my computer. Would this setup also work well as a home theater setup? My apartment is fairly small and I wouldn't be sitting more than 10 or 12 ft. away.

When you say "150 watts would be too much for near-field listening," do you mean it would be more than needed or do you mean it would actually over-power the speakers and make them sound different/worse for the application? Also, I don't understand what ohms are or what they mean for speakers and amps. Ohms are "resistance," I know, but what exactly does this mean? The higher the number the more resistance - or the other way around? Is more resistance better or worse? Do amps with 8 ohm ratings generally need to be paired with speakers with 8 ohm ratings? Are ohm ratings like db sensitivity ratings (89 db sensitivity, 1 W/1 M)?

I didn't mean to compare the two speakers, they were just both listed in the same manual. What I meant to ask, was: why would they say "this speaker wants 100 watts" on the box, but then say "this speaker IS HAPPIEST with TWICE the recommended wattage" in the manual? I have read, over and over, that it's ultimately best to just try different speakers and amps together until one finds a pair they like. I don't think I'd be here asking all these questions if I had the money/resource for that approach.

Lastly, thanks for your service, jp_over! You meet a lot of fellow audiophiles over there in Afghanistan? :p
 
jp_over

jp_over

Full Audioholic
Lots of good questions, I'll answer as best I'm able.

...and here they are; "port noise." Is this just the sound of air being sucked back and forth through the ports? Why are speakers built with ports if they sound bad?
Not sure on the technical ins and outs of port noise - simply put, one member here mentioned he heard unwanted noise from the speakers. He designed some mods to fix the noise / port noise. I've never noticed this on mine.

Ports are not problematic, as a general rule, from quality speaker designers / companies.

What does it mean to "cross something over?" When you saying "playing them full range," does this mean you're not cutting out lower frequencies that would otherwise be diverted to a subwoofer?
Yes; when I said crossing them over I meant cutting out lower frequencies. On my speakers, I don't cut out anything and hence run them full range.

What defines "near field listening?" I plan on using this setup for production and general listening with my computer. Would this setup also work well as a home theater setup? My apartment is fairly small and I wouldn't be sitting more than 10 or 12 ft. away.
Nearfield for me means sitting at my desk (3-4 feet away from the speakers). Would it work well for home theater setup (10-12 feet) - I listen to mine from that distance and they sound fine. I've seen some debate on whether they would make good home theater speakers. I think they're fine but your listening habits might be different from mine (I rarely listen at high volume levels.).

When you say "150 watts would be too much for near-field listening," do you mean it would be more than needed or do you mean it would actually over-power the speakers and make them sound different/worse for the application?
I think it would be too loud. Also, it's beyond what the speakers are rated for (100 watts). If you over power them, you could damage them. I don't know how they would react to high wattage levels (over 100 watts) and I wouldn't recommend it.

Also, I don't understand what ohms are or what they mean for speakers and amps. Ohms are "resistance," I know, but what exactly does this mean? The higher the number the more resistance - or the other way around? Is more resistance better or worse? Do amps with 8 ohm ratings generally need to be paired with speakers with 8 ohm ratings? Are ohm ratings like db sensitivity ratings (89 db sensitivity, 1 W/1 M)?
Perhaps a little searching is in order on this one - I don't have the full answer to explain it simply. In short, most AVRs and amps will let you know in the manual what ohm load they can play (common speakers are 4, 6, or 8 ohms). I'd stay within the AVR/amp specifications as recommended.

I didn't mean to compare the two speakers, they were just both listed in the same manual. What I meant to ask, was: why would they say "this speaker wants 100 watts" on the box, but then say "this speaker IS HAPPIEST with TWICE the recommended wattage" in the manual? I have read, over and over, that it's ultimately best to just try different speakers and amps together until one finds a pair they like. I don't think I'd be here asking all these questions if I had the money/resource for that approach.
I think quality solid state amps pretty much all sound the same when operating within their limits but there are definitely other opinions out there. Do some searching and you'll see debate on this one (enough to make a good decision I'm sure).

Not sure about the manual references but I can tell you that 90 watts per channel is plenty for these speakers to get quite loud.

Lastly, thanks for your service, jp_over! You meet a lot of fellow audiophiles over there in Afghanistan? :p
You're welcome. I meet more audiophiles than one would think here but still not too many!
 
fightinkraut

fightinkraut

Full Audioholic
I use the 2030P's paired with a Dayton Sub-100 and am very pleased by the combo, for a budget set up I've found nothing else that compares. Near field, current amplification is an old Teac stereo receiver that can't be putting too much out, maybe 50 watts. I hope to purchase the DTA-100a sometime in the future, wound up purchasing a couch a while ago and that sort of whittled down available funds. :rolleyes:

BTW, great questions, thanks for responding to JP's advice in an intelligent manner!
 
Quilope

Quilope

Enthusiast
Thanks again, jp_over for your insight and also to you, fightinkraut. I tried to read up as much as I could before posing questions, because I don't want to be wasting anyone's time, here - including my own :) I know I am asking a LOT of questions. I suppose I should go out and find some kind of "intro to sound engineering" or something like that.

I originally was looking at the Dayton SUB-80, but I'm wondering if the 10" SUB-100 would be better? Do I need to have two subs or could I just get away with one 10? Yeah, "budget" is where it's at for me, right now.

Obviously speakers are designed differently depending on the intended purpose. Do near-field monitors have such a narrow "sweet spot" that they really lose it when you go outside of it (too close or too far away)? Are things like cinema speakers and loudspeakers made to have more "throw" or just a more uniform sound at a much wider range of distance?

Right now, I'm pretty much sold on the B2030P's and either a Dayton SUB-80 or 100. It seems like Behringer is a **** company on almost all accounts, but somehow hit a fluke homer on the 2030's? Reverse engineering? IDK. I'm just happy that there is something out there that is pretty awesome at this price-point! Monoprice cables, some banana plugs... and then I just need to decide on an amp. There are a couple Tripath amps I'm considering; namely one of Arjen Helder's Tripath TA2020 MKII 25w. It's a DIY kit though, and I don't know if I'm ready for that yet... I'm leaning towards the DTA-100a.

I've read as much as I think I can stomach at this point about Tripath chips, D class amps and so-on. It seems that a lot of the audio snobs and true audiophiles are not totally in love with class D amps in general, but it also seems like they are about 50 X cheaper than something they would be content with. And, of course, comes the REAL question: would I be able to hear the difference, anyway? No matter what, this new setup will be a huge step up for me, and I'M STOKED!!!!
 
Quilope

Quilope

Enthusiast
WmAx wrote this on another thread;

(4) Onkyo SR505 receiver is recommended.($150-$200 each). You can use this as an integrated amp. Very importantly: it has a variable active xover to limit LF to the main speakes and limit HF to the subwoofers, to help integrate them properly. If you want to use number 5 option below, any stand alone amp with enough power is sufficient, since no. 5 option is also a powerful crossover. If you want to still use stand alone amp, but want to cheap out on the xover, see no. 6.

(5) Optional, but incredibly superb in optimizing sound to your preference and further integrating the mains and subwoofers perfectly: Behringer DCX2496($275). A very powerful DSP device that you can link to your computer w/serial cable for GUI control if so desired. This device is magnitudes more sophisticated than a plug-in EQ for you media player. This device does not distort when you push up bands high, and it has far greater precision and flexibility in manipulating the signal. It is also a precision crossover that will be better than the one built into the Onkyo receiver; or any receiver for that matter. You would use the receiver's direct in amp inputs if you use the DCX. You would need to place a pre-amp before the DCX. Or, use your computer sound card volume control.

(6) Optional, and higher quality and superior to most receiver xovers, is a Behringer CX2310($90 each) 2 way stereo 4th order active crossover. This is an analogue unit; and of very high quality, despite it's low cost. You can use any stand alone amplifier w/enough power to drive the speakers, by using this xover. You will need to use a pre-amp before the xover, or use the sound card volume control.
Am I to understand I also will need some type of crossover device somewhere? Is the CX2310 a decent piece of hardware? Is this something that is not necessary?

Also, purely out of curiosity, has anyone out there ever used either a ZVEX iMPAMP or a Decware Zen Triode (both tube amps). I'd be especially curious to know how they perform with speakers like the B2030P's...
 
jp_over

jp_over

Full Audioholic
Thanks again, jp_over for your insight and also to you, fightinkraut. I tried to read up as much as I could before posing questions, because I don't want to be wasting anyone's time, here - including my own I know I am asking a LOT of questions. I suppose I should go out and find some kind of "intro to sound engineering" or something like that.
Glad to help. This forum has helped me out more times than I can count (even before I began posting)!

I don't know much about the processor-type equipment such as the CX2310 or DCX2496 (though I plan on learning at some point) so I can't help you there. From my understanding, they provide great flexibility but you'll need to spend some time with the instruction manual.

I originally was looking at the Dayton SUB-80, but I'm wondering if the 10" SUB-100 would be better? Do I need to have two subs or could I just get away with one 10? Yeah, "budget" is where it's at for me, right now.
I'd go with the 10" and then if you're not happy, buy one more. For nearfield use, one should be plenty (of course, depending on your listening habits). From what I've heard, an 8" is just not enough unless you spend quite a bit more/buy a higher end model and even then you're compromising because you're spending more than you would for a larger model with greater performance. Caveat: I don't own and have not heard either the Dayton 8" or 10" - simply stating what I've seen/read about 8" woofers in general terms.

I can't really help with the amp part as I haven't done any research on those mentioned. I bought a $100 receiver (shipped) from an e-bay "top rated seller" and it suits my needs.

Last note, this dayton has a crossover device built in:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-633

Good luck with your search; it's 1/2 the fun! :D
 
Quilope

Quilope

Enthusiast
I don't know much about the processor-type equipment such as the CX2310 or DCX2496 (though I plan on learning at some point) so I can't help you there. From my understanding, they provide great flexibility but you'll need to spend some time with the instruction manual.
Yeah, I don't always have the most patience, but I guess the payoff would be the dangling carrot for me. This guy's got one, but I think he's really drunk or something - I can't understand what he's saying...

http://www.youtube.com/watch?v=maaddMxVcJk

I'd go with the 10" and then if you're not happy, buy one more. For nearfield use, one should be plenty (of course, depending on your listening habits). From what I've heard, an 8" is just not enough...
That is exactly what I wast thinking. I guess my major concern was whether I'd have good frequency coverage with a 10" EG would there be a gap between the woofer in the B2030P and the 10" sub driver that wouldn't be present with an 8" sub. I don't need it to be super loud - I plan on doing basic audio production and I live in a pretty close-quarters apt. building. I just want it to sound goooooood!!:D

Last note, this dayton has a crossover device built in:

http://www.parts-express.com/pe/show...number=300-633

Good luck with your search; it's 1/2 the fun!
That reminded me to check the Behringer manual, and those bad-boys have crossovers built in, too. So, assuming the built in crossovers in both the speaker and sub are decent, no extra component is needed. In the very least, it's something that can wait 'til later. I'm hoping.

At times this feels more like a wild goose chase than a search, but it's true: I am having fun :) I'm learning a ton, too! I think I've learned more in the past three days reading about all this than I did in all of high school. Heh...
<_<
>_>
 
fightinkraut

fightinkraut

Full Audioholic
Quick comment, I have the CX2310 and love it, using it for sub EQ in my HT. Easy to use when incorporated with REW, an incredible piece of free software.

I'd 100% recommend the 10" over the 8", for the minor price difference it will provide a more satisfying sound.

You're correct you do not need the CX2310, the advantage of using it in a set up like you mentioned is that the crossover within the sub is a 12dB/octave, which means you'll have some sound overlap near your crossover point, it's not as tight an adjustment as is provided by a unit such as the CX2310. So, if you use the DTA-100a + Sub-100 + 2030P, you'll need to send the speaker level outputs from the amp into the sub, then use the high pass filter on the sub to send the speaker wire out to your speakers. This is how I'm doing it for now and am quite pleased with the sound, it's not perfect, but it is a great budget option.
 
Quilope

Quilope

Enthusiast
So, after all was said and done, I ended up with a pair of Ascend Acoustics CBM-170 SE's used off Audiogon. Now I'm trying to find a good amp to power them. I was looking at an Emotiva UPA-2. The XPA-2 looks awesome, but I'm living in a tiny apartment right now, so I think the smaller one would be more appropriate. I made an offer on one on Audiogon, but if it falls through, I think I'll buy a DTA 100A and an HT SUB-100.

Earlier today a friend randomly offered me an Onkyo TX-4500 receiver that she doesn't want. I told her I'd go home and research it a little, and from what I've read it seems like it could be a decent piece of hardware. I do have a couple questions, though;

1. A receiver is what? A device that can receive a radio signal? Also, some receivers have amps built in?

The manual for the TX-4500 says:

65 watts per channel, min. RMS, at 4 ohms both channels driven from 20 Hz to 20 kHz, with no more than 0.1% total harmonic distortion. 55 watts per channel, min. RMS, at 8 ohms both channels driven, from 20 Hz to 20 kHz, with no more than 0.1% total harmonic distortion.
75 watts per channel, min. RMS, at 4 ohms both channels driven 1 kHz, 0.1% THD.
60 watts per channel, min RMS, at 8 ohms, both channels driven, 1 kHz,
0.1% THD
0.1% at rated power
0.08% at 1 watts output
0.3% at rated power
0.1% at 1 watts output
50 (8 ohms 1 kHz 10 watts)
15-30,000 Hz (± 1 dB)
2-80,000 Hz (±1 dB at main amplifier)

I understand almost none of this ^ :confused: Which brings me to my next question...

2. How can something be rated for 4 ohms and 8 ohms at the same time? Does the receiver/amp somehow know how many ohms the speakers want or will I blow something up if I plug a 4 ohm device into 8 ohm speakers? The CBM-170 SE's I have want a minimum of 25 watts at 8 ohms. Would this receiver be good and/or appropriate to power them?

3. For Inputs is says:

phono 1 & 2, tape play 1, 2 & 3, dolby in, main in FM and AM antenna.

So, are the phono and tape inputs just a bunch of RCA in's?

Will all of my music suddenly sound like it's from the 70's if I use this amp? :D
 
GranteedEV

GranteedEV

Audioholic Ninja
1. A receiver is what? A device that can receive a radio signal? Also, some receivers have amps built in?
A receiver is an integrated amp with a tuner.
An integrated amp is an amplifier with a built-in preamplifier and volume control.

I understand almost none of this ^ :confused: Which brings me to my next question...

2. How can something be rated for 4 ohms and 8 ohms at the same time? Does the receiver/amp somehow know how many ohms the speakers want or will I blow something up if I plug a 4 ohm device into 8 ohm speakers? The CBM-170 SE's I have want a minimum of 25 watts at 8 ohms. Would this receiver be good and/or appropriate to power them?
Let's start by defining a few things.

Impedance. It means to "prevent" or "oppose" an alternating current. It is measured in ohms.

Current. Think of it as "flow of electricity" - the actual movement of the electricity.

Voltage. Think of it as something which stimulates current against impedance. A potential or force of a sort.

Now we have to consider a speaker's impedance profile. It varies with frequency. That means at some frequencies, a speaker resists the flow of current more than it does at other frequencies. Here is the CBM 170's impedance profile (top graph) and phase (bottom graph).



As you can see, from around 100 - 500hz, the speaker is below 6 ohms. Above that, the speaker rises all the way up to 14 ohms and usually its efficiency happens to rise - it needs less electric power to produce the same acoustic power at these frequencies.

So now you realize that the way the amplifier "sees" the speaker depends on the frequency you send to it. Sometimes the speaker won't ask for much current delivery and sometimes it will ask for a ton. Look again at the top graph above.

What you want is an amp that produces notably more power as impedance drops. This means that when the speaker needs more current to produce 200hz for example, it will deliver it. So if an amp states 200 watts at 4 ohms, 100 watts at 8 ohms, and 400 watts at 2 ohms, you know you're covered. That's an ideal amp and of course they're not that perfect. Still, if you can get a 65-80% increase in "rated power" as you go down in impedance you are going to have plenty of available current for the speaker should it ask for it.

Phase angle is also really important. Read this:

http://sound.westhost.com/patd.htm

3. For Inputs is says:

phono 1 & 2, tape play 1, 2 & 3, dolby in, main in FM and AM antenna.

So, are the phono and tape inputs just a bunch of RCA in's?

Will all of my music suddenly sound like it's from the 70's if I use this amp? :D
Tape is likely an RCA in which is perfectly fine. Phono inputs are a bit more complex and I don't know a thing about them :D
 
J

jostenmeat

Audioholic Spartan
Quilope, congrats on those speakers, I find them to be very impressive for their price. They won't win a beauty pageant; this is for the person who wants their dollars going to toward the performance aspect, IMO.

Not trying at all to diminish Grant's excellent description of a common concept of a speaker's power demands on an amplifier . . . . but I believe those speakers are pretty easy to drive. My friend drove them with an ancient* and cheap looking piece of hardware, and they sounded great, however he was not cranking HT stuff out of them, but classical music.

If you look at the graph supplied by Grant (even if I immediately guess its the mftr's own, but it's what we have), all of the impedance spots that are lowest (most demanding) seem to always coincide with a 0 degree phase angle (highest power factor; efficiency), which basically means that you'll be fine with almost anything driving them. My guess is that the power handling of the drivers/speakers themselves will be the lowest common denominator in how hard/long you can drive them.

Ok here are some NRC measurements of impedance and phase angle of the older/superceded/previous version of the 170. Not "SE".





http://www.soundstagemagazine.com/measurements/ascend_cbm170/
 
Quilope

Quilope

Enthusiast
Whoa! Thank you both GranteedEV and jostenmeat.

OK, a lot to take in here.


A receiver is an integrated amp with a tuner.
An integrated amp is an amplifier with a built-in preamplifier and volume control.
OK, so the Emotiva UPA-2 is an amplifier because it has no controls - it needs to have a preamp to control it.

The Dayton Audio DTA 100A is an integrated amp because it has it's own volume control.

Still a little unclear as to what a "preamp" is... does that just tell the amp what to do? EG "this is how much power you should be pumping out right now, Mr. Amp, because Mr. Speaker is asking for x-amount of juice at this exact second."

Impedance. It means to "prevent" or "oppose" an alternating current. It is measured in ohms.
OK, so the more impedance the harder it is for the current to flow? Or is it the other way around? It sounds like the opposite of what I was thinking. The lower the ohm rating, the less impedance, the harder it is for the electricity to come through. I guess I'll have to read that article and try to make sense of it.

That graph was a little confusing to me because the axes aren't labeled. The X (horizontal) axis is frequency, right? And the Y axis is ohms on the top and phase on the bottom, but I don't know what is meant by "degrees of phase." Once again, maybe that article will help.

Tape is likely an RCA in which is perfectly fine. Phono inputs are a bit more complex and I don't know a thing about them.
So the inputs are actually very different depending on what's what, eh? I thought an input just meant a place to plug in cables that are carrying a signal. Yeesh, I hope my ignorance isn't showing too much, here... So, if I were going to use, say... my laptop as a source - going out of the headphone out on my laptop and into one of the "tape" inputs, the TX-4500 would be happy with that? What about the UPA-2? The laptop wouldn't act as a "preamp," would it?

Quilope, congrats on those speakers, I find them to be very impressive for their price. They won't win a beauty pageant; this is for the person who wants their dollars going to toward the performance aspect, IMO.
Thanks!! Yeah, that's what attracted me to them, I think. Performance. I couldn't care less about the looks of something, TBH. In fact I kind of like it when things are ugly, but perform like beautifully. They will be less likely to be stolen, this way, I think...

My guess is that the power handling of the drivers/speakers themselves will be the lowest common denominator in how hard/long you can drive them.
I'm a little confused, here... You're saying the speakers will be the weakest link?

Ok here are some NRC measurements of impedance and phase angle...
NRC?
 
J

jostenmeat

Audioholic Spartan
I think you have the gist of the nomenclature down.

The more impedance, yeah that seems counterintuitive perhaps, but I guess maybe think of it as a valve that can be opened. The lower the impedance the more the valve is opened for tons of water to start pouring through. Bad analogy I know, but you have to pretend that when the "impedance" of the valve drops to nothing that it'll all blow up and catch on fire. :p

I am saying that with a "decent" amplifier, that your speakers will likely be the weakest link in terms of being first to blow (as my unknowing guess). Sure, you can fry drivers with less power, as the amp clips the signal, with tweeters being the more common victim.

NRC is the most famous of all audio measuring facilities in the world, it's in Canada.
 

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