Welcome, Guest
Username: Password: Remember me

TOPIC: Re:High efficiency twoway plus sub - a first try

High efficiency twoway plus sub - a first try 9 years 8 months ago #45

  • Complex
  • Complex's Avatar
  • Offline
  • Junior Boarder
  • Posts: 36
  • Karma: 10
Hallo,

so here´s my first MiniDSP-powered Project.



Its a HiFi RT8 II tweeter combined with an Precision Devices PDN 10MH25.
I chose these drivers for my first experiments wit the MiniDSP because both have average SPL > 95db, so any hum or noise eventually produced by the MiniDSP would be unviled.

The boxes where just quickly glued together from some spare MDF i had lying around, ugly but functional.

So far i only connected my PC to the Input of MiniDSP and Set the Crossoverfrequnecy to 1800 Hz LR, and did som Tweaking with the EQ and connected 2 old stereoamps.

Sounded pretty good so far, but missing the base, as the PrecisionDevices ist more of an High SPL PA-Mid.
So, to get adequate subbase-performance I conneced 2 21" Woofers through a pair of plateamps who do their own crossing-over.

Well, im´m far from done yet, but right now I just listen an enjoy, because the sound is already realley good.

As next step I will try to get my measureing-system fully working, so i can tweak with the EQ a little bit more.

My wishes, that arosw fron ny first experiments to the MiniDSP development team so far:
- An Bandpassfilter for the low branch of the crossover, so I can filter out the subbase-frequnecy´s from the PD, as they are Reproduced by my subwoofer anywhay. This woud also be usable as subsonic filter in other twowayapplications.
- Changeable filterorders, would allow more freedom, for exaple to cross over an Tweeter even lower.
- I´d really rather not have an 31 band EQ, and have some Parametric EQ´s instead - with selection of Q-factor and, most important, an shelving filter to correct Bafflestep etc.


So, that´s it for now - I will write more, when I´m successful with my measuring-system.


So Long,
Daniel
Attachments:
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 8 months ago #46

  • devteam
  • devteam's Avatar
  • Offline
  • Administrator
  • Posts: 8533
  • Thank you received: 1050
  • Karma: 157
Hello Daniel,

Nice to see that you're making great progress on your project!
Is that a closed box or rear vented?

Keep sending updates on your project, it's really useful for us to hear feedback and see the real projects. Everybody gets to enjoy it!

As for your wishes, we've already added them to our wish-list as per your previous post... Haven't started working on them yet as we're swamped with hardware now, but will schedule them for the next few weeks. Some of them will be easy to implement while others (modifying too much the architecture of the DSP) will not be possible within the same plug-in, but instead will require a new plug-in Basically, for people to make sure they don't loose their settings and can upgrade easily, we can't modify greatly the DSP architecture of a plug-in. We however can do tricks in the background but to some extends, so we'll see what we can do.

For the Parametric vs Graphic equalizer, it's interesting that you're raising this point as we've thought for a long time on which one we should provide. Our feeling was that only not everybody would actually understand how a PEQ works. (hence the choice of a graphic, something everybody have seen in winamp/win media player). Now, I believe that having the choice between graphic and PEQ is a great idea so i'll look into what it takes to make it happen.

Take care and thanks for the update,

Tony
MiniDSP, building a DIY DSP community one board at a time.
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 8 months ago #47

  • Complex
  • Complex's Avatar
  • Offline
  • Junior Boarder
  • Posts: 36
  • Karma: 10
Hello,

It´s closed-box, with a little eq-ing at the low end.
Today I got something measured, althoug not representable. I think my Mic-Preamp dosn´t do enougth amplification to get a good signal.

I also noticed a sligth 1db difference in signal-levles of the left/right channels, but it could be my old stereo-amp.
Unfortunatly my 4x100 Watt T-Amp from shure thkes his time to geht to Germany :unsure:

Anyway, I tweaked the setup a little more and I´m really happy with the results right now.

I´m curios what´s the best way to regulate volume.
I could either regulate it through an preamp before the MiniDSP,
with an 4-way potentiometer after the MiniDSP
or, I think i read something about an MiniDSP internal volume-regulator to wich i´d just have to connect 1 single potentiomet?


,
Daniel
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 8 months ago #48

  • devteam
  • devteam's Avatar
  • Offline
  • Administrator
  • Posts: 8533
  • Thank you received: 1050
  • Karma: 157
Daniel,

Yes that's correct, you can use a potentiometer connected to one of the header. Have a look at the miniDSP manual on how to connect that potentiometer. If you have any questions/doubt, just send your questions to us.

The advantage in doing so is that you'll get a strong signal at the input of the ADC. One of the important step in making a DSP processed system (or any ADC as a matter of fact), is to make sure that your Signal to Noise Ratio (SNR) is good. If you feed your miniDSP board with a "tiny" signal, you'll be close to the noise floor of the ADC and no matter how good of an ADC you have, it won't sound good.

It's much better to have a strong signal on the input of the ADC (with enough headroom) and then attenuate at the amplifier or within the DSP. Hope this makes a bit of sense. Hence my recommendation of using the digital volume control with a single pot.

Let me know how that works for you and looking forward to seeing the measurements of your powered speaker!

Tony
MiniDSP, building a DIY DSP community one board at a time.
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 8 months ago #67

  • Rundberg
  • Rundberg's Avatar
  • Offline
  • Junior Boarder
  • Posts: 23
  • Karma: 4
Hi Daniel,

Did you trz to plaz a bit with the graphic EQ for the baffle step? In the same way I think you would be able to attenuate the lower frequencies (that you send to the sub anyway) using the graphical EQ.

Please post some measurements, it would be very interesting to see :)
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 8 months ago #68

  • Complex
  • Complex's Avatar
  • Offline
  • Junior Boarder
  • Posts: 36
  • Karma: 10
Hello.

Yes, Bafflestepcompesation is no problem with the G.EQ, but the filtering of the lower frequnecys ist not ideal because you can only attenuate 12db. Still better then nothing.

I´m afraid at the moment my measuring-sytem only help´s me guessing because my Mic/Preamp combination is obviusly not sufficent - and I still have my problems with the ARTA-Software :blush:

I´m currently trying to finde some matching bass-drivers. Thinking of 4x15" maybe Beyma 15LW30 or Eminence Deltalite 2515. They should run to about ~300 Hz, perhaps I willl go 4-way with this?

This will thake some time thoug - I´ll report back if I have news. Currently waiting for my 4-channel Amp.
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 8 months ago #72

  • devteam
  • devteam's Avatar
  • Offline
  • Administrator
  • Posts: 8533
  • Thank you received: 1050
  • Karma: 157
Thanks for the follow up Daniel, we'll be looking forward to hearing news and reports once your 4 channel Amp arrives. So is the plan to have a 3 way setup? (Bass + Mid + High)?

What's your problem with your ARTA measurement setup? Maybe you can share to see what could be the issue... Free field measurement of subwoofers are typically very difficult. The work around for most manufacturers is to perform what's so called: "Ground plane measurement". In my previous engineering jobs, I used to perform these kind of tests a lot on ProAudio line array speakers (live sound). I'd recommend you google it to see if that would help your measurements.

Take care
MiniDSP, building a DIY DSP community one board at a time.
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 8 months ago #78

  • Complex
  • Complex's Avatar
  • Offline
  • Junior Boarder
  • Posts: 36
  • Karma: 10
Hello,

my amps arrived yesterday, yay :woohoo:

U are right, i´m currently thinking 3 or maybe 4-Way. Have to frind the rigth midbass first. Also thinking about some small self-powered bookshelf speaker with those cute little T-Amps. So maybe i´ll nee 2 more DSP´s in February ;)

The main problem with my measuringequipment ist, i only get a mic-levle of ~70db in my soundcard ... but there´s a good communtiy in Germay - I think someone there will know what´s wrong.

Greets,
Daniel
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 8 months ago #79

  • devteam
  • devteam's Avatar
  • Offline
  • Administrator
  • Posts: 8533
  • Thank you received: 1050
  • Karma: 157
Cool, so with the amps, you're all set now! :-)

That measurement issue sounds like a mic calibration problem. Typically, in systems like MLSSA, Clio, TEF, AP, you need to have an external SPL meter to initially calibrate your microphone / input gain of sound card / software... Not sure if you did it already but that may be worth investigating.. Getting a low cost handheld & calibrated SPL meter will be a good start to help calibration of your system.
Some software may let you input the mic sensitivity (looking at the spec sheet of your mic) and will convert the voltage reading to an equivalent SPL value. Not as accurate, but will still get the job done.

Keep up the progress! We're looking forward to seeing the end results!
MiniDSP, building a DIY DSP community one board at a time.
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 6 months ago #291

  • Complex
  • Complex's Avatar
  • Offline
  • Junior Boarder
  • Posts: 36
  • Karma: 10
Hello,

I´m finally makeing some progress here. Will fetch my 2xDSP+Amp+Digi kit from the customs tomorrow.
Two woofer-testcabinets are ready too. Equipped with Eminence Deltalite II 2515.
Picture attached.
Attachments:
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 6 months ago #337

  • Complex
  • Complex's Avatar
  • Offline
  • Junior Boarder
  • Posts: 36
  • Karma: 10
Hello,

planning my 4-way stereo-setup, some questions arose:

1) Input selection: Can I connect a 4-Way Switch to the inputselection jumper on MiniDIGI to switch sources - or should this be changed only when powered off?

2) I understand that I only have to connect the PSU to the MiniAMP. In my Configuration I´ll have to miniAMP´s. Any problems to expect, like gound loops?

3) "Power Down" and "Mute" on MinAmp: I assume I can use this as an ON/OFF switch and mute button - should i use a twoway switch or can I run the jumpers of the two AMP-boards over the same switch?

4) Why do I need 2 MiniDIGI´s - shouldn´t I be able to get the Input from one MiniDIGI to MiniDSP1 and from there to MiniDSP2 to, as MiniDSP1 put´s out the unprocessed signal from in7/8 to out7/8.
It seems a bit strange to me to loop the second channel trough DIGI1 first, converting it an extra 2 times. Doesen´t this add some delay to the second channel?

I think i got the rest rigth, now - so first mono testruns and, hopefully some measurments will be made this weekend!

greetings from Germany,
Daniel
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 6 months ago #339

  • devteam
  • devteam's Avatar
  • Offline
  • Administrator
  • Posts: 8533
  • Thank you received: 1050
  • Karma: 157
Hello Daniel,

Glad to hear that you're making good progress on your project!
1) Input selection: Can I connect a 4-Way Switch to the inputselection jumper on MiniDIGI to switch sources - or should this be changed only when powered off?
Yes, that's not a problem at all to use a 4 way switch. Just toggling from one of the inputs. That's how we're doing A/B test here and realized the difference between listening to a fiber and Spdif input (with and without XFMR)... So no need to power off.
2) I understand that I only have to connect the PSU to the MiniAMP. In my Configuration I´ll have to miniAMP´s. Any problems to expect, like gound loops?
Please clarify how you're planning to mount these together. Are you talking of these 2 stacks (miniDSP + miniAMP for 2 stacks would be best since you'll notice that you can't easily stack 2 x miniAMP (caps height)). Digital in, I2S amp, forget about ground loops. :-)

3) "Power Down" and "Mute" on MinAmp: I assume I can use this as an ON/OFF switch and mute button - should i use a twoway switch or can I run the jumpers of the two AMP-boards over the same switch?
PDN stops all clocks and outputs stop switching. When PDN is released, the device powers up all logic, starts all clocks, and performs a soft start that returns to the previous configuration.. The mute control provides a noiseless volume ramp to silence. Releasing mute provides a noiseless ramp to previous volume.. In the end similar effect that audio will turn off. :-) I think that either switch is enough, but you can do both if you want. miniAMP doesn't thump on power on so you should have to worry about the difference between either modes.
4) Why do I need 2 MiniDIGI´s - shouldn´t I be able to get the Input from one MiniDIGI to MiniDSP1 and from there to MiniDSP2 to, as MiniDSP1 put´s out the unprocessed signal from in7/8 to out7/8.
It seems a bit strange to me to loop the second channel trough DIGI1 first, converting it an extra 2 times. Doesn´t this add some delay to the second channel?
Two miniDigi are required to link up 2 boards together in an active configuration. If you have all boards in the same box, then indeed you wouldn't need that configuration. What you just highlighted with connecting both in7/8 would work.
MiniDSP, building a DIY DSP community one board at a time.
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 6 months ago #341

  • Complex
  • Complex's Avatar
  • Offline
  • Junior Boarder
  • Posts: 36
  • Karma: 10
Hello,

thank´s for the quick answers!

1) Good to hear. This will make it easy to connect both my computer and my CD-player :woohoo:

2) I´ll add a picture to clarifi that.

3) The main question was: Can i switch mute for two AMP´s with one switch
(like controlling the volume of 2 DSP´s with one Mono 10k pot.)

wicht leads me to question 5)
wich is the best way to connect the volume control in a stack?
Should I remove the respective pins of the board-to-board interconnect or should i just solder onto the pins of the corner-plug?


btw. i got it working 4 way (in Mono) right now. After getting some noise first, I realised my mistake in setting the I2S routing jumpers on the mini-digi. Now it plays, absolutly noiseless via optical in from my PC.
Was a lot easier in the end than alle the documentation let me to believe in the first place!
The Deltalite shows a really promising sonic performance. I´ll try and do some measurements this weekend.

I got a suggestion though regarding the power connector: I currently run the stack with an old notebook PSU @20V 3,5A wich luckily fits - but I was not abel to find another connector to power the second stack. All other I have lying around are either to big at the outside or to small at the inside diameter. I´d be a lot happier to just have screw-terminals - that would save time and money - and once mounted in a box, it would even lower the risk of a plug comeing loose.
Attachments:
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 6 months ago #342

  • fb
  • fb's Avatar
  • Offline
  • Junior Boarder
  • Posts: 25
  • Karma: 2
admin wrote:
Two miniDigi are required to link up 2 boards together in an active configuration. If you have all boards in the same box, then indeed you wouldn't need that configuration. What you just highlighted with connecting both in7/8 would work.

How does one need to setup the master/slave settings for the miniDSP and miniDIGI boards in this configuration?
The administrator has disabled public write access.

Re:High efficiency twoway plus sub - a first try 9 years 5 months ago #349

  • devteam
  • devteam's Avatar
  • Offline
  • Administrator
  • Posts: 8533
  • Thank you received: 1050
  • Karma: 157
Daniel,

Here are a couple of points to clarify your setup:
The main question was: Can i switch mute for two AMP´s with one switch
(like controlling the volume of 2 DSP´s with one Mono 10k pot.)
Yes you can, that's not a problem.
Which is the best way to connect the volume control in a stack?
I think that the easiest may be soldering but that depends on your skills. In the future versions of this boards, we plan to add a Pot header to help that connectivity.

One general comment about about your diagram. In my previous post when I said that you could connect a single miniDIGI to both miniDSP 7&8, I may have spoke too fast (Which happens when you write email at the end of your day :-)
Actually, you can't connect 2 miniDSP together as you pointed out because they would both be as miniDSP I2S master(by default), and would conflict with each others..

By default connecting 2 x miniDSP together wasn't intended because it requires more work to setup correctly each board and a bit more understanding than a typical plug&play setup.We're in the progress of writing an app note on how to, but in the mean time, I'd please ask that you wait on that app note to come out (and for us to complete a clear explanation on how to do it) such that you don't potentially damage your board. I seem to recall that you have 2 miniDIGI so maybe try that for the time being, then we'll have a look at the configuration you suggested later on. Thanks for your patience.
btw. i got it working 4 way (in Mono) right now.
Glad to hear that you got your setup working with little trouble. We plan to release diagrams sometime in the next few weeks with clearer explanation to make sure there aren't any confusion on the jumper configuration.

As for your power connector, dully noted suggestion. We'll have a look at it when we manufacture another batch, but for now on, the 2.5mm barrel will be the solution. We do plan to source a local PSU as an accessory which will simplify the setup for end users.

Hope this helps.


DevTeam
MiniDSP, building a DIY DSP community one board at a time.
The administrator has disabled public write access.
Moderators: devteam