Some thoughts on DSP, and an embarrassing confession

[Sydney]

Re: Some thoughts on DSP, and an embarrassing confession

haha
( you know you are into sound when you remember screen gems like that :D )

[Paul Carmody]

Re: Some thoughts on DSP, and an embarrassing confession

Maybe I didn't understand what you were saying in your blog or this post. Why is dsp a duct tape fix and why is it not useful in multi driver speakers? That makes no sense...

To clarify, I thought we were talking about simple graphic EQ plugins like you see on a desktop computer or phone. To me, that's a duct tape fix.

What I mean with regards to multi-way speakers is that, in order to really do the job right, you need to shape each individual driver's response (like a passive crossover would). Obviously, this is what devices like MiniDSP are made for, but then you need amplification for each driver.

I keep thinking we might be getting close to a DSP/amplification solution DIYers could use. Squeeze a (programmable) DSP chip and an amp on the same board. You could then design your "crossover" using some sort of software, safe the config to a flash memory on the DSP, mount the board in a speaker enclosure, wire up the drivers to the amp outputs of the board, and call it good. These are the sort of cool toys the manufacturers of bluetooth speakers and active pro audio monitors have to work with. But maybe it's just a matter of time until we hobbyists get something like that, too. :D

[mattsk8]

Re: Some thoughts on DSP, and an embarrassing confession

What I mean with regards to multi-way speakers is that, in order to really do the job right, you need to shape each individual driver's response (like a passive crossover would). Obviously, this is what devices like MiniDSP are made for, but then you need amplification for each driver...

But maybe it's just a matter of time until we hobbyists get something like that, too. :D

All this needs is more channels, but you could get 2 (one for each loudspeaker). MiniDSP PWR-ICE Series

IMO, this is the future.

[Wolf]

Re: Some thoughts on DSP, and an embarrassing confession

There is a cutaway view of the Jawbones both large and small somewhere on the net. I have the small one- rarely use it. The thing is heavy for it's size, and bass starts to distort early in the volume chain. The small version appears to have a tweeter placed in between the 2 FR units, and I don't think it's PR loaded. The larger version is and is the only way they'd be able to achieve the bass they get since it's tuned relatively high in that small volume. I can dig mine out and see what I can discern more as the memory of it is a tad fuzzy. I do remember that it does have a NASTY turn on thump.

Heck- I can bring it to Meniscus if anybody wants me to.

Later,
Wolf

[Face]

Re: Some thoughts on DSP, and an embarrassing confession

To clarify, I thought we were talking about simple EQ plugins like you see on a desktop computer or phone. To me, that's a duct tape fix.

Check out "Available DSPs"

http://wiki.jriver.com/index.php/DSP

Output options: https://yabb.jriver.com/interact/ind...&topic=85141.0

Just pick your multi-channel sound card and amp modules.

And there's also this: http://www.bodziosoftware.com.au/

[Kevin K.]

Re: Some thoughts on DSP, and an embarrassing confession

To clarify, I thought we were talking about simple graphic EQ plugins like you see on a desktop computer or phone. To me, that's a duct tape fix.

What I mean with regards to multi-way speakers is that, in order to really do the job right, you need to shape each individual driver's response (like a passive crossover would). Obviously, this is what devices like MiniDSP are made for, but then you need amplification for each driver.

I keep thinking we might be getting close to a DSP/amplification solution DIYers could use. Squeeze a (programmable) DSP chip and an amp on the same board. You could then design your "crossover" using some sort of software, safe the config to a flash memory on the DSP, mount the board in a speaker enclosure, wire up the drivers to the amp outputs of the board, and call it good. These are the sort of cool toys the manufacturers of bluetooth speakers and active pro audio monitors have to work with. But maybe it's just a matter of time until we hobbyists get something like that, too. :D

Isn't this what you are talking about?

http://www.minidsp.com/products/plate-amplifiers/pwr-ice125

Sorry, I was posting the same thing Matt did, he beat me to it.

[ksneote]

Re: Some thoughts on DSP, and an embarrassing confession

Is there any benefit or drawback when comparing active vs passive crossovers? I understand how an active crossover is easier to tweak, and probably make as you aren't limited by the components (or prices) available. But if you were to have two identical speakers, some crossover, one is just passive and active, would the sound identical? Aside from the passive requiring some more power I suppose, due to the components taking some power.

[3ll3d00d]

Re: Some thoughts on DSP, and an embarrassing confession

a cutdown version of http://www.audiovero.de/en/preamp-14-cleanvolver.php combined with an amp would be nice

[Sydney]

Re: Some thoughts on DSP, and an embarrassing confession

Is there any benefit or drawback when comparing active vs passive crossovers? ... But if you were to have two identical speakers, some crossover, one is just passive and active, would the sound identical? ...

Uh Oh
Depends who you ask :D

[ryanbouma]

Re: Some thoughts on DSP, and an embarrassing confession

To clarify, I thought we were talking about simple graphic EQ plugins like you see on a desktop computer or phone. To me, that's a duct tape fix.

Oh ok, gotcha. I've done it to correct for sealed roll off, but ya, not very useful.

What I mean with regards to multi-way speakers is that, in order to really do the job right, you need to shape each individual driver's response (like a passive crossover would). Obviously, this is what devices like MiniDSP are made for, but then you need amplification for each driver.

I'd agree. But dsp can be applied to a passive speaker to correct for bass response issues that you were addressing in your blog. I do it quite often.

I keep thinking we might be getting close to a DSP/amplification solution DIYers could use. Squeeze a (programmable) DSP chip and an amp on the same board. You could then design your "crossover" using some sort of software, safe the config to a flash memory on the DSP, mount the board in a speaker enclosure, wire up the drivers to the amp outputs of the board, and call it good. These are the sort of cool toys the manufacturers of bluetooth speakers and active pro audio monitors have to work with. But maybe it's just a matter of time until we hobbyists get something like that, too. :D

There are some options. Hypex and minidsp offer plate amp solutions like this. They're a bit costly though. I keep wanting to get a pair though. I've also considered a Sure 4x100 board with a 2x4 minidsp all in one case. Two inputs, a power input, two speakons out using both the 1 & 2 carriers. Almost as simple as a passive speaker. Cost would be around $300 I figure. Not bad for a single box with only 5 cords required. I can't think of a more convenient way to do active speakers. And I've been trying to find a way. The only other easy way is available plate amps (cost more and would need to plug power cords into both speakers) or dsp pro amps (much less convenient IMO due to xlr inputs and would need two boxes).

[mattsk8]

Re: Some thoughts on DSP, and an embarrassing confession

Is there any benefit or drawback when comparing active vs passive crossovers? I understand how an active crossover is easier to tweak, and probably make as you aren't limited by the components (or prices) available. But if you were to have two identical speakers, some crossover, one is just passive and active, would the sound identical? Aside from the passive requiring some more power I suppose, due to the components taking some power.

I'll bite... lets get this war started... :eek:. Yes there are a few benefits to active. First, you're manipulating the signal before the amp sees it, rather than manipulating the power going to the driver, so the amp gets to basically run free. 2nd, sensitivity is no longer an issue. I have heard the ATC SCM-40 (passive), right next to the exact same speaker, only it's the SCM40A (active). Between those 2, the active was hands down better sounding than the passive version.

The downside to active is that power isn't cheap, and instead of needing one 2 channel amp for a pair of passive crossed 3 ways (for example), you'll either need three 2 channel amps, or one 6 channel, etc. Imagine doing an all active 5.1 channel HT system, where each TM was also active.

[Paul Carmody]

Re: Some thoughts on DSP, and an embarrassing confession

Is there any benefit or drawback when comparing active vs passive crossovers? I understand how an active crossover is easier to tweak, and probably make as you aren't limited by the components (or prices) available. But if you were to have two identical speakers, some crossover, one is just passive and active, would the sound identical? Aside from the passive requiring some more power I suppose, due to the components taking some power.

Well, if you look back early on in the "House Sound" thread you'll see me mention that I have a certain sound I like to get from my designs. So if I were given the same drivers, and told to do an active and passive version, they would have a very similar sound, yes.

The slippery slope you're approaching is that active newbies like to think that they can just plug in "4th order Linkwitz Riley, cross at 2400 Hz" and suddenly they'll have a great speaker. The same mindset that doesn't understand why a "premade, off the shelf" crossover sounds so bad. In order to design a high quality speaker--active or passive--you need to take the drivers' individual Frequency Response into account and shape it accordingly. This still takes a skilled ear, I believe.

So in the end, the tools don't matter so much. The great speaker is dependent on the skills of a designer.

[Paul Carmody]

Re: Some thoughts on DSP, and an embarrassing confession

There are some options. Hypex and minidsp offer plate amp solutions like this. They're a bit costly though. I keep wanting to get a pair though. I've also considered a Sure 4x100 board with a 2x4 minidsp all in one case. Two inputs, a power input, two speakons out using both the 1 & 2 carriers. Almost as simple as a passive speaker. Cost would be around $300 I figure. Not bad for a single box with only 5 cords required. I can't think of a more convenient way to do active speakers. And I've been trying to find a way. The only other easy way is available plate amps (cost more and would need to plug power cords into both speakers) or dsp pro amps (much less convenient IMO due to xlr inputs and would need two boxes).

Yeah, that's about the state of the art for hobbyists at this point. Workable, but still somewhat costly and big, not to mention a few extra wires.

What I'd like to see is something like what the Raspberry Pi does. A single board, the size of a playing card, with easy-to-understand inputs and outputs. This would be approachable to the hobbyists and woodworkers alike. I think it could happen. Heck, the mini bluetooth speaker manufacturers already have it!

[Sydney]

Re: Some thoughts on DSP, and an embarrassing confession

I'll bite... lets get this war started... :eek:. ...

Are you sure - In this heat wave?
Logic dictates that there must be some advantages or why would anyone have bothered to go that route as far back as the 1970's...

[ksneote]

Re: Some thoughts on DSP, and an embarrassing confession

I always seem to ask the complex or controversial questions, heh. If this topic is going to derail the thread, I can start a new one.

I'll bite... lets get this war started... :eek:. Yes there are a few benefits to active. First, you're manipulating the signal before the amp sees it, rather than manipulating the power going to the driver, so the amp gets to basically run free. 2nd, sensitivity is no longer an issue. I have heard the ATC SCM-40 (passive), right next to the exact same speaker, only it's the SCM40A (active). Between those 2, the active was hands down better sounding than the passive version.

The downside to active is that power isn't cheap, and instead of needing one 2 channel amp for a pair of passive crossed 3 ways (for example), you'll either need three 2 channel amps, or one 6 channel, etc. Imagine doing an all active 5.1 channel HT system, where each TM was also active.

So what load does the amp see then? Sensitivity of the individual drivers, right? Because you can amp them separately, and to whatever level you want with no need to pad the tweeter?

Well, if you look back early on in the "House Sound" thread you'll see me mention that I have a certain sound I like to get from my designs. So if I were given the same drivers, and told to do an active and passive version, they would have a very similar sound, yes.

The slippery slope you're approaching is that active newbies like to think that they can just plug in "4th order Linkwitz Riley, cross at 2400 Hz" and suddenly they'll have a great speaker. The same mindset that doesn't understand why a "premade, off the shelf" crossover sounds so bad. In order to design a high quality speaker--active or passive--you need to take the drivers' individual Frequency Response into account and shape it accordingly. This still takes a skilled ear, I believe.

So in the end, the tools don't matter so much. The great speaker is dependent on the skills of a designer.

Of course, I wasn't implying the use of a "generic" crossover when using active, just comparing a similar crossover order type etc, active vs passive.