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Push Pull Slot Loaded quad SI HT18s


MemX

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Er... yep!  :facepalm: lol

 

It's not helped by me picking up an Emo XPR-5 off another very kind gent for a pretty bargain price for the power it puts out, so now my 200w MK speakers are being spanked with 600w@4Ohm... :D

 

So far they are coping admirably but Dredd just about blew them apart when I attempted it at Reference, it's recorded so hot!  Crossovers now raised and extra care being taken... lol

 

 

Those are gorgeous!! That finish looks great man. I love seeing those drivers too. It's adds an industrial element to the room. I'm sure whatever you paid it was worth it since James did great work.

 

Hope you get your mic situation straightened out. It was a pita on my system too and that was with Paul's help. The UMIK is a great mic for $100 it's just that it has a 125db limit on it so I'm sure your subs will clip it. Only thing to do is take measurements below those levels and know going in anything above that will be clipped to hell.

 

I do feel bad for that TV. :P

So far the TV is fine... *crosses finger* :ph34r:

 

I like the slightly industrial look blended with classy dark wood (stained veneer) finish too, it is very 'me', so these couldn't have turned out better!  Thanks for the kind words :)

 

I'll order a mic later tonight I think, 120dB is madness in my room so I don't think I'll be doing much testing above that anyway! :blink::lol:

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My wife would love that look too. While they're not small, the finish is fantastic, and if you can incorporate them into a room the way you did, would look great anywhere. No matter where you move you have some great looking subs MemX. :)

 

I don't buy the whole 'so I don't think I'll be doing much testing above that anyway!" Sooner or later it will happen haha.

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Actually physically moving them if we move is the main issue, James reckoned they must weigh about 200lb each! lol  It was a slight challenge carrying them up the stairs... :blink:

 

I will have to move them into any new place we get after dark, otherwise the neighbours will instantly be scared / complaining :lol: lol

 

I think you are probably right about the testing thing, though, just give it time... ;)

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  • 4 weeks later...
Quick update!
 

I ran The Art of Flight BD this morning at Reference but +9dB on the subwoofer trim on the AVR.

Peaks of 119dB at the MLP (around 10 feet from the stacked subs) and 126dB close-mic'd at the mouth of the slot of one of the subs.

I'm sure there is a lot more to give (the cones were barely moving, perhaps 5mm peak-to-peak) and I do need to check my gain structure and also sort out this EQ for the very bottom end (miniDSP is on the way, as is a calibrated UMIK) but it was great to have a back massage while sitting on the sofa silly.gif

I'm not sure the neighbours will be too impressed if I play it that loud regularly, but it's nice to know that I have plenty of headroom!
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  • 1 month later...

Ok, to stop me cluttering up madaeel's thread ;) I'll update here!

 

 

Missus came home the other day as I was playing track two off John Hopkins' 'Immunity' album:

http://www.amazon.co.uk/Immunity-Jon-Hopkins/dp/B00CCCF4NW/

 

Apparently it's pretty loud in the car park 50 yards away and through concrete block walls and double glazing when playing at -11 but +9dB from where Audyssey set the SW trim :ph34r: so if I get time/money, I'll have to look at soundproofing the ceiling... lol

 

 

Anyway, graphs!  Below are what I think is an accurate loopback measurement of the Onkyo 818 (REW on the Computer > USB > Behringer UCA202 soundcard > RCA > Aux In on the front panel > SW Pre-out > RCA > Soundcard) along with close-mic sweeps in one of the two slots (audyssey on and off), MLP sweeps (audyssey on and off) and second LP sweeps (audyssey on and off), and also a graph that combines these three.

 

Questions and issues already raised by the helpful 3ll3d00d on the other forum we're on include asking why the roll-off is so steep on the close-mic measurement, and the fact that the massive 30Hz null only looks fixable by moving the entire sofa, as his REW screen capture (also posted) illustrates! :wacko:

 

 

One step forward... lol

 

 

Onkyo 818 loopback measurement 2014.12.bmp

 

PPSL close-mic sweeps 2014.12.30 - Audyssey on and off.bmp

 

PPSL MLP sweeps 2014.12.30 - Audyssey on and off.bmp

 

PPSL 2LP sweeps 2014.12.30 - Audyssey on and off.bmp

 

PPSL close-mic + MLP + 2LP sweeps 2014.12.30 - Audyssey off.bmp

 

REW Room Sim null calculations 2014.12 from 3ll3d00d.bmp

 

 

 

EDIT:  I have no idea why these aren't showing up in the post... I assume because they're .bmp and not .jpg??

 

 

post-932-0-15630000-1421777393_thumb.jpg

 

post-932-0-82365100-1421777408_thumb.jpg

 

post-932-0-52571800-1421777419_thumb.jpg

 

post-932-0-65067200-1421777427_thumb.jpg

 

post-932-0-44384000-1421777439_thumb.jpg

 

EDIT2:  That's better, although I can't get the last file, the REW Room Sim file, to upload as it's too big as a jpeg...

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Yah a 20db drop from 20-10hz and also that Onkyo is showing flat to below 2hz? Something ain't right.

That's what I don't understand - you can see from the flat line of the soundcard calibration that the compensation of the calibration is correct, and if I'm just going out from the soundcard, through the AVR and back to the soundcard, I'm sure I'm doing it right?? :wacko:

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Yah I can't help you there as Paul helped me with mine and if there's any problems I call him haha. It's just I've never seen any preamp or AVR not start to roll off at the very least around 3hz. That looks like it would be flat to 0....

 

You're using a UMIK too right?

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Yah I can't help you there as Paul helped me with mine and if there's any problems I call him haha. It's just I've never seen any preamp or AVR not start to roll off at the very least around 3hz. That looks like it would be flat to 0....

 

You're using a UMIK too right?

I'm not sure when I'll get a chance to play and see what I've done wrong (if anything) but hopefully soon...  I've started chopping up cables for the miniDSP so a step in the right direction at least! :D

 

I do also have a UMIK, it's the calibrated version from CSL and was used for the MLP and 2LP sweeps in the graphs :)  Looks to be good to 7Hz and pretty good to 5Hz, so better than the audyssey mic and the SPL meter, but I don't think I'm going to be able to measure the real ULF that Bosso can! lol

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  • 4 weeks later...

Well, in the absence of me actually breaking out the mic and doing any measuring, due to work and studying (and laziness :ph34r: ) I can at least report one thing:

 

Tron Legacy at -9.5MV but bumped +6dB on the SW trim at 11pm at night does not equal happy neighbours... :ph34r:

 

Oops.

 

 

I feel bad :( and now paranoid about how loud I can go!

 

 

It's not unexpected, admittedly, but I will have to reserve the really loud stuff for a day off when everyone is at work, or an evening when I can see everyone is out...

 

Apparently the woman downstairs was swearing at me while hammering the front door down and hanging off the buzzer, but I didn't hear her for obvious reasons :ph34r:

 

Next door was annoyed too as it was getting late - she is more tolerant, fortunately, and the apology flowers bought have helped calm troubled waters, but I've not had a chance to speak to downstairs yet!  Always good to meet your neighbours for the first time when they are angry at you... :facepalm: lol

 

 

Ho hum!

 

I need a detached house badly...

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You're an asshole. :lol:  :lol:

 

Man I did the same thing once with some crappy JBL subs. If I was my neighbor I woulda called the cops haha.

lol  I do wonder if that might happen one day!

 

It's not like I was playing banging trance music for 6 hours straight, next door said it sounds like a game or something, but Tron is a bit of a bassfest so I should have turned it down!  It should hopefully mean that films that aren't non-stop bass will still be get-away-with-able...

 

*crosses fingers*

 

I knocked downstairs three times tonight to say sorry, and not quietly, but no answer,  despite them being in - if they can't hear me with their crappy 32" LCD TV speakers, I don't know what hope I have  :lol:  lol

 

I gave up in the end - I heard she had some bloke round and I didn't fancy a beating... (because I am a pussy :ph34r: )

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I knocked downstairs three times tonight to say sorry, and not quietly, but no answer,  despite them being in - if they can't hear me with their crappy 32" LCD TV speakers, I don't know what hope I have  :lol:  lol

 

I gave up in the end - I heard she had some bloke round and I didn't fancy a beating... (because I am a pussy :ph34r: )

so what you're saying is that you blasted out tron legacy late at night and got shouted at. You then followed up by hammering repeatedly on her door the next night....... slightly questionable strategy there, an asbo coming up for you  :P

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so what you're saying is that you blasted out tron legacy late at night and got shouted at. You then followed up by hammering repeatedly on her door the next night....... slightly questionable strategy there, an asbo coming up for you  :P

haha  :lol:

 

I knocked firmly but politely - you know, so it doesn't sound aggressive - but they were getting dinner ready or something while watching TV.  I *could* have rung the intercom door system from outside but I wasn't that keen to speak to her  ;)  :P

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  • 2 months later...

Bumping this thread.

 

You did such a great job on this build I just wanted to bump it for further info and discussion.

 

First, as a suggestion that has worked for me over the years, invite the neighbors over for a demo. Resist the temptation to slam the max output capability of the system into their virgin senses. Usually, after a couple of scenes, you mention that the system is coasting along and can be pushed much further, or something like that, someone will ask you to bump the level a bit. Once it's their suggestion, you can unleash hell. They'll usually offer a lot more forgiveness in the future after the demo.

 

Anyway, did you ever get the measurements sorted out? I'm curious to see the close mic vs at the seats FR.

 

Also, post more pics if you have them. The build is gorgeous and I'd like to see more of the push-pull driver porn if you have it.

 

More info is a good thing, if you get the time and inclination. :)

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Thank you for the bump and kind words :)  This community is great for support and inspiration!

 

I have considered inviting the neighbours round but I'm worried that a monolithic stack of huge subs and an amp that sounds like a hoover will freak them out before I've even pressed play :lol: lol 

 

The one bonus of the slot loading setup, though, is that they are not 'in your face' like four dustbin lid-sized 18s might be in a FF configuration - they do their job quite discreetly :)

 

 

I have been very restrained over the past couple of months because the new downstairs neighbours have moved in - an Indian couple, I can't work out if they both work funny shift patterns or if she's a stay at home wife / he's a 'work at home' husband.  This week they appear to have been out until mid-evening, whereas up till now they have seemingly always had at least one of them in at any given time of the day, which is most frustrating!  I don't want to annoy them just yet :lol: especially as I've not even spoken to them yet... lol

 

So, anyway, the upshot is that the above, being busy at work, studying, and generally being a bit 'meh' about life in general and the difficulty in improving my current financial situation, has seen me short on motivation and not doing any measuring!  I need to do a grid pattern of measurements across the MLP to identify if I can fix my 30Hz null with some slight furniture rearrangement, then move things as required (it'll ruin my feng shui, maaaan... :lol:) and then re-measure and get this miniDSP up and running for some low end boost!

 

Even without really tweaking, I'm still loving the 'transparent', 'clean' bass that seems to integrate seamlessly with the mains, thanks to Audyssey - if I can improve further and get more wobbly bottom end, I will be very happy :)  I'm hoping it will be this week that i can have a play but Thursday night is curry and alcohol with friends, Friday will probably be film night, then I have been roped into babysitting from Saturday lunchtime through to Monday morning - a relaxing weekend this will not be... lol

 

I will try for some pics when I get a chance - it's a bit tricky with them tucked behind the TV in a dark alcove, but it's pretty easy to slide out!  (The TV, that is - I will injure myself if I try to move the subs... :lol:)

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I have to say it will be fascinating to see where you end up with this given what your early measurements show up.

 

I'm not sure if MemX posted them here but basically the early MLP measurements suggest he's in a null in the mid 20s (with a falling response under that point IIRC). The room layout/dimensions posted indicate that is due to his MLP being bang on the null of his 1st axial length mode (i.e. he sits half way down the room). 

 

This means the level of improvement available, if the room can be rearranged and those measurements were accurate, could be quite immense from a last few octaves perspective.

 

Where did your old SVS used to be btw? same place as the PPSLs?

 

@MemX let me know you when you're ready to get back to work on this and we can sort out a day for me to pop over (with speclab etc) if you like.

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If you have REW, instead of doing several measurements, try using the pink noise generator and RTA functions together.  Then you can just walk the mic around the room to map out the response and see how that null behaves.  You can also use tone generator +  SPL meter functions together but you must keep in mind that the null may not go away completely but may instead shift in frequency.  The nice thing is that the better the response

 

I hope you can work something out with your neighbors.  I'm in a house now, but previously we were in a town home.  We had a single neighbor on one side, but with the construction being fairly modern, we hardly heard here or even her very large dog.  Nevertheless, one night while trying out new sub placements, we put on "Titan A.E."  At that point, I hadn't heard the soundtrack on a system with any bass at all, much less solid performance to under 20 Hz.  My jaw about dropped after the opening scene ... and then the phone rang.  It was the neighbor who was very upset to see her side of the dividing wall shaking.  For other reasons, I opted not to keep those sub placements, and thankfully, we never got another complaint even with HTTYD.

 

The nice thing is that by adjusting your MLP and placements for a better response, you avoid adding boosts that can make matters worse with the neighbors.  When there is a null in the room response at a certain frequency, the energy that would have gone to that part of the room instead concentrates somewhere else, usually at the walls and corners where it can enter the structure more readily.  If you try to boost output to correct that null you make things substantially worse.  OTOH, if you can somehow sit in the hotter part of the room resonance (which may not be possible being that it may be close to the back wall for you), then you can EQ down the response at that frequency instead and reduce the amount of energy there reaching the room surfaces.

 

Oh yeah, and another nice thing about bass is that you don't need to use very loud tones/sweeps to get good room response measurements.  I do bass measurements in my living room with my wife sleeping in an open room down the hall, and it's not a problem.  I can't get away with doing full range measurements after hours so easily.

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  • 4 weeks later...

Hi all,

 

Apologies for the delay in coming back to this, I was hoping to have pulled my finger out and been more productive so I could come back with some graphs, but I've been busy with work / studying / a touch of depression (I think), all of which has meant that I've either been too busy to get stuff done or when I've had the time, I've not had the motivation... :(

 

 

Anyway...

 

@MemX let me know you when you're ready to get back to work on this and we can sort out a day for me to pop over (with speclab etc) if you like.

 

This is a very kind offer, thank you!  I think I will have to take you up on this as technology hates me :lol: lol

 

The SVS was previously in the same place and was tamed considerably with Audyssey XT32, but it didn't sound anywhere near as 'tight' as this sealed setup.  I did think I had quite a bit of a peak in-room with the SVS but I think that must have been its tuning and how it interacted with the room, rather than the room itself, going from how the graphs I posted on the previous page seem to be relatively flat at the MLP (bar the nulls and tailing off at the bottom end...).

 

One thing I was just thinking about, though - the_dude2 said that the FoTP barrel roll sounded 'different' when he was here, like it was lacking, and I think the hypothesis was that the room null was sucking out the 30Hz considerably. But, looking at the 2LP graph on the previous page (where he was sitting when he was here) the null doesn't look that bad?  So perhaps it's a distortion-reduction thing instead??  One to look at if/when I have time/ability... lol

 

 

 

If you have REW, instead of doing several measurements, try using the pink noise generator and RTA functions together.  Then you can just walk the mic around the room to map out the response and see how that null behaves.  You can also use tone generator +  SPL meter functions together but you must keep in mind that the null may not go away completely but may instead shift in frequency.  The nice thing is that the better the response

 

I hope you can work something out with your neighbors.  I'm in a house now, but previously we were in a town home.  We had a single neighbor on one side, but with the construction being fairly modern, we hardly heard here or even her very large dog.  Nevertheless, one night while trying out new sub placements, we put on "Titan A.E."  At that point, I hadn't heard the soundtrack on a system with any bass at all, much less solid performance to under 20 Hz.  My jaw about dropped after the opening scene ... and then the phone rang.  It was the neighbor who was very upset to see her side of the dividing wall shaking.  For other reasons, I opted not to keep those sub placements, and thankfully, we never got another complaint even with HTTYD.

 

The nice thing is that by adjusting your MLP and placements for a better response, you avoid adding boosts that can make matters worse with the neighbors.  When there is a null in the room response at a certain frequency, the energy that would have gone to that part of the room instead concentrates somewhere else, usually at the walls and corners where it can enter the structure more readily.  If you try to boost output to correct that null you make things substantially worse.  OTOH, if you can somehow sit in the hotter part of the room resonance (which may not be possible being that it may be close to the back wall for you), then you can EQ down the response at that frequency instead and reduce the amount of energy there reaching the room surfaces.

 

Oh yeah, and another nice thing about bass is that you don't need to use very loud tones/sweeps to get good room response measurements.  I do bass measurements in my living room with my wife sleeping in an open room down the hall, and it's not a problem.  I can't get away with doing full range measurements after hours so easily.

 

Some great suggestions there, thanks SME :)  I was playing with the RTA thing just now and it looks like 1/6 smoothing gives good measurements without being too smoothed out, so I'll have to try that out for the walking around thing.

 

As per d00d's suggestion, though, I need to work out the calibration for this UMIK -

- AVR SW-Out LPF 'off'

- MV on the AVR at 0.0,

- Level on the REW measurement pop-up window maxed at -3.0,

- 'SPL Meter' within REW calibrated to what the UMIK is apparently putting into REW (around 73dB),

and my graphs still max out at around 106.4dB on a sweep (when clicked on on the graph). 

 

Surely it should be more?  I'm not sure the neighbours will be pleased with me doing sweeps at that level all the time either lol.  (MV at 0.0 will at least remove any effects of Audyssey boosting lower levels etc.)

 

 

EDIT:

 

Here you go - a few 0Hz-500Hz sweeps at -12 on the measurement pop up window with one at -3 (which overloaded and said it was clipping during measurement):

 

post-932-0-80412000-1432566718_thumb.jpg

 

Mic placed in the slot entrance pointing at the ceiling (so pretty much centred left-right and top-bottom), levels as detailed earlier.

 

Still getting -20dB/octave roll off at the bottom end (assuming I'm not doing this completely wrong) and it looks like the bandpass effect of the slot is starting to take effect around 170Hz, although this should be able to be calculated using slot width/depth and Hz wavelengths.  Looks pretty flat between 22Hz and 130Hz at that (extended) scale, though, so I think I should be pretty happy with it??

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Just tried to upload a more zoomed in graph to keep d00d happy ;) but file size is too large at 87kb - apparently 52kb max??  Hope I've not run out of allowance in this whole thread...

 

 

Annoying because I've also done another sweep but with Audyssey SW trim setting at 0.0 rather than the -13dB it set it to (and the measurement window Level set at -3.0) which has increased the sweep level recorded by some 20dB over the green line in the above graph...  (Although seemingly has clipped the hell out of the mic between about 20 and 120Hz so I definitely need to recalibrate it for max level sweeps!)

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As per d00d's suggestion, though, I need to work out the calibration for this UMIK -

- AVR SW-Out LPF 'off'

- MV on the AVR at 0.0,

- Level on the REW measurement pop-up window maxed at -3.0,

- 'SPL Meter' within REW calibrated to what the UMIK is apparently putting into REW (around 73dB),

and my graphs still max out at around 106.4dB on a sweep (when clicked on on the graph). 

 

Surely it should be more?  I'm not sure the neighbours will be pleased with me doing sweeps at that level all the time either lol.  (MV at 0.0 will at least remove any effects of Audyssey boosting lower levels etc.)

I'm not entirely sure what you're trying to do there, the method sounds like an approach for establishing pre out voltage (and hence gain structure) but then you talk about your mic. What are you trying to do?

 

if that is a close mic measurement then I'm not sure what you're looking for, the MLP response is what you need to examine at this point.

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