a few forum regulars reported they never could get optimum results using sub woofers in FAST designs. not sure why but, probably could be done with more complex EQ rather than choosing a simple 2 way Xover at the BSC frequency and dialing-in the seperate amp gains.
not sure if you have lived happily with your Jordan in a different full range box beforehand, I reckon you need to get that sorted before moving forward with any woofer replacement, EQ enhancement strategy or expectations. IMO having a single horizontal baffle for stereo doesn't make your job easy to engineer in a straight forward manner either.
what was the reason for spacing the sub woofers as you've done? might limit things, if you find yourself crossing higher up.
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NM 2.1 amp) for some reason I thought you had 4 way amp in there, this not a true FAST design
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Indeed, your logic suggests that you are clever and putting the amp board on one side and the PSU on the opposite side would take benefits from simmetry ?!
(the PSU is the amp, the power stage just "modulates" DC into AC ...)
Ok Gents.
The winner is XRK. Thanks.
The fullrange units were indeed out of phase. The Jordan drivers do not have any polarity markings, just stickers, which may have been incorrectly placed.
Whilst I was investigating this, I decided to check whether the bass drivers were in-phase, and lo and behold, they were out also. The lesson here is don't trust the polarity on the amp, or the drivers. Check.
The result is much much better. The sound is now very coherent and seamless. I am pleased with it, and I am not walking over to turn it off all the time!
There is some work to do on the bass tuning, I think. It is a bit "flappy". I prefer something tighter.
If I did this again, I would probably use passive radiators. I would also go with miniDSP 2x4 and a pair of TPA3116, purely for flexibility. I may still do this in due course, but for now I am happy.
I have bought a UMIK-1, so I will try and do some measurements in a while.
Thanks to everyone for their input.
The winner is XRK. Thanks.
The fullrange units were indeed out of phase. The Jordan drivers do not have any polarity markings, just stickers, which may have been incorrectly placed.
Whilst I was investigating this, I decided to check whether the bass drivers were in-phase, and lo and behold, they were out also. The lesson here is don't trust the polarity on the amp, or the drivers. Check.
The result is much much better. The sound is now very coherent and seamless. I am pleased with it, and I am not walking over to turn it off all the time!
There is some work to do on the bass tuning, I think. It is a bit "flappy". I prefer something tighter.
If I did this again, I would probably use passive radiators. I would also go with miniDSP 2x4 and a pair of TPA3116, purely for flexibility. I may still do this in due course, but for now I am happy.
I have bought a UMIK-1, so I will try and do some measurements in a while.
Thanks to everyone for their input.
Try another amp?
dublin78 - A quick test to determine if it's the DDx320 - or not, is to do a temporary swap-out with your 3116, or another known good sounding amp(if you have one). This would let you know if it's the amp or your speakers/enclosure combo. Once you isolate that you can move forward with the appropriate corrective action. You may want to try an 'old fashioned' linear PSU instead of the Connex, as a contributor to the life-less sound.
Did you ever try the DDx320 with another set of speakers prior to this build? If you did, the sound it produced may gives some clues to its sonic qualities you either liked - or not.
dublin78 - A quick test to determine if it's the DDx320 - or not, is to do a temporary swap-out with your 3116, or another known good sounding amp(if you have one). This would let you know if it's the amp or your speakers/enclosure combo. Once you isolate that you can move forward with the appropriate corrective action. You may want to try an 'old fashioned' linear PSU instead of the Connex, as a contributor to the life-less sound.
Did you ever try the DDx320 with another set of speakers prior to this build? If you did, the sound it produced may gives some clues to its sonic qualities you either liked - or not.
Update:
Well, the other day, I switched on the DDX320, the display came on, but no sound. It seems kaput for no reason.
I have bought a miniDSP 2x4 and miniDIGI. Also a UMIK-1. When I get back from my holidays I will put it all together. I already have 2x TPA3116. I will convert one to bridged mono.
I have also treated myself to a pair of 17cm Accuton passive radiators which I will fit to the rear of the cabinet and block off the port tubes on the front.
It is a shame about the DDX320, but I feel that there will be much better potential with the miniDSP. Obviously I wish that I had gone down this route at the beginning, as I am now stuck with 2.1 sound, and I have wasted the money on the DDX320.
Ho hum.
Will update in due course.
Well, the other day, I switched on the DDX320, the display came on, but no sound. It seems kaput for no reason.
I have bought a miniDSP 2x4 and miniDIGI. Also a UMIK-1. When I get back from my holidays I will put it all together. I already have 2x TPA3116. I will convert one to bridged mono.
I have also treated myself to a pair of 17cm Accuton passive radiators which I will fit to the rear of the cabinet and block off the port tubes on the front.
It is a shame about the DDX320, but I feel that there will be much better potential with the miniDSP. Obviously I wish that I had gone down this route at the beginning, as I am now stuck with 2.1 sound, and I have wasted the money on the DDX320.
Ho hum.
Will update in due course.
So glad you got it all worked out. That phase business is a common problem. Often class D amps from China are incorrectly labeled on speaker out polarity. A 1.5v battery applied to driver terminals will show correctly polarity immediately. I often use the battery check before final wiring. 1.5v is usually safe enough not to damage drivers.
When you record a response with UMIK-1 and software like REW, the impulse response will also show incorrect polarity. A negative going peak is a tell tale sign.
Most importantly, your ears will hear that something is off - usually "phasiness" followed by anemic bass.
If you want tight bass and you will have miniDSP on board. Try sealing the vent and implementing transform - it gives decent extension and very tight low group delay. The driver you have has plenty of xmax and is ideal for a LT.
A passive radiator is like a port so the bass reflex flappiness won't most likely be improved. It may allow deeper tuning with no port length or resonance limitations. The sealed LT is an easy (and reversible) mod. Also, you can use it dial in exactly the box Q you want to have - some like 0.71 some like 0.5. I like in between at 0.62. All very easy to try though.
When you record a response with UMIK-1 and software like REW, the impulse response will also show incorrect polarity. A negative going peak is a tell tale sign.
Most importantly, your ears will hear that something is off - usually "phasiness" followed by anemic bass.
If you want tight bass and you will have miniDSP on board. Try sealing the vent and implementing transform - it gives decent extension and very tight low group delay. The driver you have has plenty of xmax and is ideal for a LT.
A passive radiator is like a port so the bass reflex flappiness won't most likely be improved. It may allow deeper tuning with no port length or resonance limitations. The sealed LT is an easy (and reversible) mod. Also, you can use it dial in exactly the box Q you want to have - some like 0.71 some like 0.5. I like in between at 0.62. All very easy to try though.
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Hi
Yes, I suspect that the terminals on the amp were incorrectly labelled. No biggie.
I will need the 2.1 plug-in from miniDSP. I don't think that it incorporates LT???
I was hoping that the PRs would reduce/avoid flappiness...
The DDX320 gave a good result. I am expecting the miniDSP to be a big improvement.
To be continued in due course.
Yes, I suspect that the terminals on the amp were incorrectly labelled. No biggie.
I will need the 2.1 plug-in from miniDSP. I don't think that it incorporates LT???
I was hoping that the PRs would reduce/avoid flappiness...
The DDX320 gave a good result. I am expecting the miniDSP to be a big improvement.
To be continued in due course.
The LT is implemented as an advanced biquad polynomial in the PEQ part of the plugin. Download the miniDSP LT calculator spreadsheet and input your current box fs and Q and desired fs and Q. You can estimate current based on measured frequency response as a sealed box. If you have an impedance measurement tool you can measure it directly drom driver terminals.
Not incorrect as it is more of a guideline than a standard. There are many drivers, particularily vintage ones, where the + on the red terminal will cause the driver to suck in. As long as the drivers are the same you should be OK.
dave
There are two examples, a TPA3116D2 (Texas Instruments) and a TDA7498 (STI Micro) PCB's where the outputs are labeled +/- and -/+ when according to the schematics and topology, it should be +/- and +/-, and the only way for a +/-, -/+ to happen is for the traces on the PCB to cross-over one another. This was not done as it was a simple 2 layer PCB with a ground plane.
There are many examples of speaker polarity or even L/R stereo blunders on major productions of class D boards. The very popular Lepai 2020+ amp has L and R reversed if you use the 3.5mm input jack. It's fine with the RCA inputs. I was the first to discover that after 350,000 views on the Lepai thread. No no noticed before that but I heard a track I was familiar with and the drums were on the wrong side of the stage.
Hallelujah
Hi
I thought that I would do an update.
Today, I took out the long hair stuffing (lightly stuffed) out of the fullrange driver compartments. I replaced it with 14g of twaron angel hair. This seemed like a lot of stuffing but 14g was recommended as a starting point for a 1.8 litre cabinet less driver and felt lining.
The difference is stunning. All of a sudden there is tons of detail and "air". This is what I was aiming for all along, when I was trying to better the SONOS Play 5. I can't believe that such a simple change has had such a result.
I have the DDX320 set with a flat EQ (no EQ). Crossover is 160Hz. I have boosted the bass by +5.
I am not convinced by the TB W5 drivers, hence the low crossover point. They just seem hollow in the low midrange area. If I was to do this again, I would try something like a Scanspeak Discovery 15W8434. I would also put the bass drivers in separate cabinets, so that I could experiment with a miniDSP two way solution (instead of 2.1) for ultimate control, if needed.
As it is now, I can finally recommend this system. I wander whether the wife will notice when she gets home.
Hi
I thought that I would do an update.
Today, I took out the long hair stuffing (lightly stuffed) out of the fullrange driver compartments. I replaced it with 14g of twaron angel hair. This seemed like a lot of stuffing but 14g was recommended as a starting point for a 1.8 litre cabinet less driver and felt lining.
The difference is stunning. All of a sudden there is tons of detail and "air". This is what I was aiming for all along, when I was trying to better the SONOS Play 5. I can't believe that such a simple change has had such a result.
I have the DDX320 set with a flat EQ (no EQ). Crossover is 160Hz. I have boosted the bass by +5.
I am not convinced by the TB W5 drivers, hence the low crossover point. They just seem hollow in the low midrange area. If I was to do this again, I would try something like a Scanspeak Discovery 15W8434. I would also put the bass drivers in separate cabinets, so that I could experiment with a miniDSP two way solution (instead of 2.1) for ultimate control, if needed.
As it is now, I can finally recommend this system. I wander whether the wife will notice when she gets home.
We've not tried the Twaron angel hair material but for standard BAF wadding, just lightly fill the box so it's full but not compressed.
Here's the link to the angel hair manufacturer's site for anyone interested
http://www.twaron-angelhair.com
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