5 Way Active Speaker build....

[Guest Peter the Greek]

12 hours ago, explorer2203 said:

No joints if single casting other than rear panel

So how are you planning on doing it?

I had considered inverting the box, pour the "top", insert a polystyrene filler for the internal volume, pour the sides, pour the base, let it set, dig out the polystyrene though the driver holes - live with a less than perfect base as you'll never see it.

[explorer2203]

So how are you planning on doing it?
I had considered inverting the box, pour the "top", insert a polystyrene filler for the internal volume, pour the sides, pour the base, let it set, dig out the polystyrene though the driver holes - live with a less than perfect base as you'll never see it.

This material is sticky. It’s not like normal concrete. So it will stick to the vertical face. You don’t pour it. You spray it or hand press it to the surface of the mould then against the next layer

[explorer2203]

Made a mistake in weight calculations. Forgot to take out the weight of the driver holes which is quite significant

Will work that out later.

Trying to find a supplier of melomine fir lengths over 2400 and width greater than 595 (Bunnings largest piece)

[hollowboy]

Sorry if I missed a post where you mentioned this, but are you still seeking 12" woofers?

 

I have more parts than I need, including 4 x SB Acoustics SB34NRX75-6 12" Woofer.  It is tested + discussed on this page:

http://www.zaphaudio.com/SB12.3/

 

$100 each.

 

I tested them, and used a pair of them briefly, but they have spent most of their lives sitting in their original boxes.

[explorer2203]

Sorry if I missed a post where you mentioned this, but are you still seeking 12" woofers?
 
I have more parts than I need, including 4 x SB Acoustics SB34NRX75-6 12" Woofer.  It is tested + discussed on this page:
http://www.zaphaudio.com/SB12.3/
 
$100 each.
 
I tested them, and used a pair of them briefly, but they have spent most of their lives sitting in their original boxes.

Are they the closed box ones? I know they have two designs. One for open and one closed.

Definitely interested. I purchased some 15’s peerless but my ideal was the 12” SB!!

[hollowboy]

The SB34NRX75-6 has a high-ish Qts, making it fairly typical for a closed box speaker.  That's how Zaph used them in the linked build.

 

Note (1) within reason, in a DSP build, you can force the LF response to be whatever you want.  Therefore (in my opinion) Qts of woofers doesn't matter as much as it used to.

 

Note (2) I'm not sure why you'd want the SB 12s over Peerless 15s.

 

...but I'm happy to make the sale if that's what you fancy

 

Do you have any contacts / family in Melbourne?  I'd be happy to demo the drivers to a 3rd party, so you'd know you wouldn't be paying for duds.

 

 

[davewantsmoore]

On 20/11/2018 at 1:14 PM, hollowboy said:

Qts of woofers doesn't matter as much as it used to.

Yes - understatement.

 

Within reason it's completely irrelevant for predicting the final response, if any type of EQ is to be used.

[explorer2203]

The SB34NRX75-6 has a high-ish Qts, making it fairly typical for a closed box speaker.  That's how Zaph used them in the linked build.
 
Note (1) within reason, in a DSP build, you can force the LF response to be whatever you want.  Therefore (in my opinion) Qts of woofers doesn't matter as much as it used to.
 
Note (2) I'm not sure why you'd want the SB 12s over Peerless 15s.
 
...but I'm happy to make the sale if that's what you fancy [emoji4]
 
Do you have any contacts / family in Melbourne?  I'd be happy to demo the drivers to a 3rd party, so you'd know you wouldn't be paying for duds.
 
 

I was of the view that the 15 inch peerless were a budget driver compared to the SB 12’s. they were my pick but failed the budget test so went with the peerless.

If I went with the 12’s I can drop height from 2.5m to 2.4 which saves me hundreds in mould costs. 2.5 is a custom piece. 2.4 is available at Bunnings for $40. They will effectively pay for themselves

What does everyone think? 15” peerless or 12” SB’s?

Or, I could go 15, 12, 8, 6 or 4 then tweets.

Feedback please!!!

But I will still buy them regardless [emoji16]

[davewantsmoore]

9 minutes ago, explorer2203 said:

What does everyone think? 15” peerless or 12” SB’s?

Which model Peerless 15"?

 

To compare them....

 

What is the planned crossover point to the 8" driver?  (I'll assume it's <200Hz)

I assume there will be no subwoofer?

I assume you want the woofer in a sealed box?

How loud and low are you going to ask the woofer to play?

[explorer2203]

Which model Peerless 15"?
 
To compare them....
 
What is the planned crossover point to the 8" driver?  (I'll assume it's I assume there will be no subwoofer?
I assume you want the woofer in a sealed box?
How loud and low are you going to ask the woofer to play?

I knew you would ask difficult questions lol

No subs. They for home theatre in my opinion not two channel.

How low should they go?

The peerless are as follows: FSL-1520R02-08

[andyr]

1 hour ago, explorer2203 said:

No subs. They for home theatre in my opinion not two channel.

 

You are mistaken, e. 

 

I only have a stereo music system.  The improvement in the enjoyment of my sound after I added 2 subs to my active 3-way Maggies was amazing.

 

A sub delivers flat to at least 20Hz - so, sure, if you have very large mains which do this ... you don't need subs.  But most mains can be improved with a pair of subs ... and some careful integration.

 

1 hour ago, explorer2203 said:

How low should they go?

 

Depends what music you like to listen to. 

 

Andy

 

[explorer2203]

 
Depends what music you like to listen to. 
 
Andy
 

Usually listen to rock, pop, a bit of classical. Jazz, Kanye west and oomph oomph music banned

[Wozza_Lee]

As a rule 'most' (i know I know) music when mastered gets cut off below 35Hz.

This is because most music systems used by the masses are not able to produce music that low and only creates distortion in a common car/radio set up. I know this isn't fair and it is also why lossless audio etc often sounds better, because of the mastering not the quality.

This information comes straight from a friend who works in the studio at Australia's biggest recording studio.

[explorer2203]

As a rule 'most' (i know I know) music when mastered gets cut off below 35Hz.

This is because most music systems used by the masses are not able to produce music that low and only creates distortion in a common car/radio set up. I know this isn't fair and it is also why lossless audio etc often sounds better, because of the mastering not the quality.

This information comes straight from a friend who works in the studio at Australia's biggest recording studio.

Good info! I rarely listen to music that is not lossless these days. You can pick the added detail

[andyr]

8 hours ago, explorer2203 said:

Usually listen to rock, pop, a bit of classical. Jazz, Kanye west and oomph oomph music banned

 

 

I can store 4 different XO configs in my miniDSP - and flick between them on the fly.  So it is easy to compare:

• subs on (24dB LP/HP XO @ 100Hz) with
• subs off - with my Maggie mains going full range (which deliver to ~35Hz).

 

In terms of rock and classical, listeners can clearly hear the enhancement which the subs deliver on:

• "The Mission" soundtrack
• the bass drum on the HFOT version of The Eagles 'Hotel California', and
• just about any Yello track.

Hence I never have the subs switched off.

 

Andy

[davewantsmoore]

11 hours ago, explorer2203 said:

I knew you would ask difficult questions lol

It's a hard decision for you, because you don't have enough "information" 

 

11 hours ago, explorer2203 said:

No subs. They for home theatre in my opinion not two channel.

What's the difference?    There's gunfire in my music, and music in my action movie.    The soundwaves don't know or care.  High quality bass reproduction has the same requirements whether your're reproducing dinosaurs, drums, strings plucking, or cars crashing. 

 

11 hours ago, explorer2203 said:

How low should they go?

When we look at recordings of music .... we find that the idea that it "only contains frequencies down to X" is a total myth.   Short sounds (eg. a pluck, band, doink, or tink) are wide-bandwidth, and contain frequencies all the way up and down the spectrum, right down to very low Hz.

 

The reality is that some production techniques intentionally (or accidentally) remove these low frequencies.

 

So you could say that they should go extremely low....  although the issue is the poor quality bass reproduction is dramatically worse than none.   So if you're going to try to make 10Hz, then it will sound bad if done poorly.

 

 

.... but it's not an academic question.   For the same SPL and same distortion ..... to move from a cutoff of 40Hz to 20Hz..... You need 4 times as much drivers .... and then 4 times as much drivers again to get to 10Hz.

 

So, for example, if 2 drivers per side was going to get you to 40Hz (it should get you much lower than this) at some SPL and distortion ..... then to get to 10Hz with the same SPL and distortion, you would need 32 drivers per side (!!!!!)

 

11 hours ago, explorer2203 said:

The peerless are as follows: FSL-1520R02-08

Oh.

There's no contest here.

 

Going by their reported linear excursion ....  The SB 12" driver has 12dB (15 times) more SPL output than the 15" Peerless driver.

[davewantsmoore]

9 hours ago, Wozza_Lee said:

As a rule 'most' (i know I know) music when mastered gets cut off below 35Hz.

Definitely not the music I listen to   

 

9 hours ago, Wozza_Lee said:

This information comes straight from a friend who works in the studio at Australia's biggest recording studio.

It's very very easy to confirm this information, by looking at actual the actual spectrum of a specific recording.

 

Lots of music does have content well below 35Hz ..... but, IME most people don't notice if they don't hear it  (because they are not used to hearing it).

 

I'm yet to encounter any lossy versions of music (eg. something sold through iTunes, or Amazon, or Google, etc.) which have a different spectrum  (eg. more/less bass, treble, etc.)

[explorer2203]

Oh.
There's no contest here.
 
Going by their reported linear excursion ....  The SB 12" driver has 12dB (15 times) more SPL output than the 15" Peerless driver.

Excellent. Thank you.

I will use the 15’s for something else

[explorer2203]

4 hours ago, andyr said:

 

I can store 4 different XO configs in my miniDSP - and flick between them on the fly.  So it is easy to compare:

• subs on (24dB LP/HP XO @ 100Hz) with
• subs off - with my Maggie mains going full range (which deliver to ~35Hz).

 

In terms of rock and classical, listeners can clearly hear the enhancement which the subs deliver on:

• "The Mission" soundtrack
• the bass drum on the HFOT version of The Eagles 'Hotel California', and
• just about any Yello track.

Hence I never have the subs switched off.

 

Andy

 

I run 2 x VAF subs on my 11.2 system. Excellent. To be honest I never hooked them up specifically to my reference Emotiva / VAF or Duntech system. Just never felt I needed it. You have me curious now so will have a play at some point once this project

[davewantsmoore]

2 hours ago, explorer2203 said:

 

I run 2 x VAF subs on my 11.2 system. Excellent. To be honest I never hooked them up specifically to my reference Emotiva / VAF or Duntech system. Just never felt I needed it. You have me curious now so will have a play at some point once this project

 

You're going to have 4x 12" drivers as "subwoofers" in your speakers.     What you will miss out on, is not being able to place them in the room where they work best.   The speakers will have the placed where the mid/treble works best.

[hollowboy]

3 hours ago, davewantsmoore said:

 

What you will miss out on, is not being able to place them in the room where they work best.

OP: if you look up "harman subwoofer placement", you'll find a good tutorial on this topic.  Or try "geddes subwoofer placement" (different authors, similar message).

 

I don't follow my own advice (I don't have this sort of subwoofer setup), but that's how I would do it if I had the space / flexibility / was doing a build from scratch.

[Wozza_Lee]

I like the sub crawl

[andyr]

18 minutes ago, Wozza_Lee said:

I like the sub crawl

 

Curious to know what you mean by that, Wozza. 

 

Andy

 

[Wozza_Lee]

Literally put your sub in the main listening position (in your chair) and then crawl around the room like a 6 month old until it 'sounds the best' to you. Swap places with the sub, drink beers and enjoy

[andyr]

1 hour ago, Wozza_Lee said:

Literally put your sub in the main listening position (in your chair) and then crawl around the room like a 6 month old until it 'sounds the best' to you. Swap places with the sub, drink beers and enjoy

 

That's what I suspected you meant, WL - but you could've also been referring to how some subs bounce around on the floor, at high excursions. 

 

In my case - no crawling around was needed.  In designing the new 'music room' a few years ago ... after discussions with Paul Spencer (who provided the subs) there was only one place for them - in each front-wall corner. 

 

And they deliver 16Hz organ tones! 

 

Andy