JKN_PHL_2017_TOWERS

[jkn]

I'm about to build a PHL base (drivers) Towers using these drivers per side

PHL - 2off 18" 7031 (bass drivers)

PHL - 2off 8" 2420 (mid.bass drivers)

PHL- 2off 6.5"1130 (midrange drivers)

SCAN SPEAK 1off 2.5" 9 (Tweter)

I came out with two different design options but unsure which to choose any input appreciated 

Option one: (wide)

Option 2: (narrow)

Edited July 16, 2017 by jkn

[Weka]

You need to measure the midrange and bass-mid drivers on some test baffles and determine where the baffle step response is going to be in relation to the desired or optimum x-over points.

 

[jkn]

Thanks for that I have received similar suggestion earlier from a friend of mine.

   

working out at what frequency the baffle step will be for each of the drivers. I doubt it will be an issue for the tweeter or 18 inch driver but I am not sure about the mid and upper base.

[davewantsmoore]

As well as the 'baffle-step' .... the change in cabinet size will affect the coverage pattern of the drivers.   aka.   directivity, or polar response.

 

ie.  the cabinet shape is important for the response of the drivers at different angles of radiation.

[jkn]

Hi Dave

I forgot to mentioned that in both options "wide or narrow" the internal volume is going remain the same.

So if I measure one driver let say PHL 6.5"midrange in sealed enclosure with narrow front baffle then take measurements of the same driver mounted in the same sealed enclosure with temporally made wide baffle would that be something I should be doing to determinate which option design to choose from?

 

The Option one (wide)I do like for a visual aspect  and I don't need extra frame to hold the top 18" 

The downside is provably overall weight particularly if you want to measure the 3 way outside (without the 18").

 

Option two (narrow) perhaps not as nice looking extra stand needed but provably is going to measure better

I have not seen any conventional sealed speakers using wide front baffle so there must be a reason.?

Any input appreciated Jiri 

  

  

[Bonecrusher]

Option 1. Great looking project.

[murrmax]

2 hours ago, Bonecrusher said:

Option 1. Great looking project.

 

Agreed; how tall will they be 3m? 

 

Quote

 

[Weka]

@jkn  I'd suggest calculating the baffle width so the acoustic roll-off of the mid ties in with the cross-over to the bass so as to simplify that electrical filter section. Keep the cabinet width the same top to bottom and heavily bevel the side sections between the bass drivers to vary width as many other manufacturers do.

 

[jkn]

7 hours ago, murrmax said:

Agreed; how tall will they be 3m? 

Somewhere about 2.5 - 2.6m

 

6 hours ago, Weka said:

heavily bevel the side sections between the bass drivers to vary width as many other manufacturers do.

 

I'm sorry but do not know what you actually mean by that

[Weka]

4 hours ago, jkn said:

 

I'm sorry but do not know what you actually mean by that

 

Something like this, but deeper...

 

 

Edited July 4, 2017 by Weka

[jkn]

Thanks for the reply I see what you meant.

 I was also thinking to curve the front baffle.

 

[Weka]

You won't gain anything beneficial by curving the baffle face - better to large radius curve the baffle edges to minimize diffraction.

[georgepapa]

You could probably do away with the 8" drivers and make it a 3way instead. Those woofers would surely transition well with the 6.5" drivers over 400hz. 

Just suggesting how you can knock down the height . These are massive on the scale of a FOH PA system. Would be great for an orchestra in a auditorium, but for the home??

Just a single 18" woofer with the 6.5" mids and scanspeak tweeter would still provide limitless powerhandling and a more focussed soundstage for  the smaller listening area in your home. 

Edited July 6, 2017 by georgepapa

[jkn]

7 hours ago, georgepapa said:

You could probably do away with the 8" drivers and make it a 3way instead. Those woofers would surely transition well with the 6.5" drivers over 400hz. 

These particular 8” drivers (which I already have in my temporally system) will not work very well in 3 way .

120Hz >500>750Hz in sealed enclosure works very well crossing to Midrange

7 hours ago, georgepapa said:

Just suggesting how you can knock down the height . These are massive on the scale of a FOH PA system. Would be great for an orchestra in a auditorium, but for the home??

 I do agree the height is a bit scary and I also agree that they are overkill BUT I have them, both running now and where they place and how they are set up they hardly break 45hz >minimum boost...

7 hours ago, georgepapa said:

Just a single 18" woofer with the 6.5" mids and scanspeak tweeter would still provide limitless powerhandling and a more focussed soundstage for  the smaller listening area in your home. 

These particular 18” will not work well going up to the midrange. I do have some PHL 6.5 midbass drivers and they work much better in 3 way however going 4 way I find it much better    

[Guest Peter the Greek]

Very noice. I like option 1 from a visual perspective.

 

Active or passive?

 

Is baffle step needed if active?

[murrmax]

Quote

These particular 18” will not work well going up to the midrange. I do have some PHL 6.5 midbass drivers and they work much better in 3 way however going 4 way I find it much better    

 

Agree , it really is a 4 way concept, what about replacing the 8's with 10's or 12's? 

 

[jkn]

On 07/07/2017 at 6:51 PM, Peter the Greek said:

Very noice. I like option 1 from a visual perspective.

 

Active or passive?

 

Is baffle step needed if active?

I do like it too and will provably settle on this.

System, is active using deqx x2 

[jkn]

On 07/07/2017 at 8:38 PM, murrmax said:

Agree , it really is a 4 way concept, what about replacing the 8's with 10's or 12's? 

That's right with these drivers 4 way is the only option.

I was thinking about the 10 and I have tested 10 "PHL recently >it would be good option the only downside is that tweeter would be higher ( I'm trying to get the tweeter position as low as possible)  

[A9X]

On 09/07/2017 at 5:06 AM, jkn said:

That's right with these drivers 4 way is the only option.

I was thinking about the 10 and I have tested 10 "PHL recently >it would be good option the only downside is that tweeter would be higher ( I'm trying to get the tweeter position as low as possible)  

Why? Do you listen sitting on the floor? Ideally the tweets should be at your seated ear height especially with a vertically symmetrical system. Might not be for some others depending in the vertical polars, but even then listening axis will usually be between the mid and tweet.

 

Terry's system is a PHL 18/10/6 + some regularly exploding horrible dome* and sounds very good. It also has a pair of sealed Maelstrom 18's and 2x DEQX (xovers circa 40,200,600,2k). His is at the right height for a lowing chair.

 

I'd go with the wide option. It'll help with baffle step and reducing excursion and distortion at the bottom of the lower MB's range.

 

* Confession; never heard a dome I really like. And in my opinion, it will not keep up with the rest of the system and will definitely be it's limitation. Look at an AMT like one of the Beymas.

Edited July 20, 2017 by A9X
Added something. Nag, nag, nag.

[jkn]

On 20/07/2017 at 0:54 PM, A9X said:

Why? Do you listen sitting on the floor? Ideally the tweets should be at your seated ear height especially with a vertically symmetrical system. Might not be for some others depending in the vertical polars, but even then listening axis will usually be between the mid and tweet.

Because

476+234+188+60= 958 mm and that is measurements of drivers only If you add a enclosures you looking at another 140+ 60 as per propose design and that is minimum now that will bring the centre of tweeter at around 1160 mm. My ear height is at about 900 mm

On 20/07/2017 at 0:54 PM, A9X said:

Terry's system is a PHL 18/10/6 + some regularly exploding horrible dome* and sounds very good. It also has a pair of sealed Maelstrom 18's and 2x DEQX (xovers circa 40,200,600,2k). His is at the right height for a lowing chair.

I have been to Terry’s place some time back and have auditioned his earlier system. His advantage is that his speaker with PHL drivers are is in one box which makes it much easier to reduce the height

I do agree with you his system sounded very good even then> I also believe that his room plays a big role as well    

 

On 20/07/2017 at 0:54 PM, A9X said:

I'd go with the wide option. It'll help with baffle step and reducing excursion and distortion at the bottom of the lower MB's range.

Still deciding >interesting thing >wide baffle will help with baffle step I was getting the impression that that wide baffle will do the opposite ...   

 

On 20/07/2017 at 0:54 PM, A9X said:

Confession; never heard a dome I really like. And in my opinion, it will not keep up with the rest of the system and will definitely be it's limitation. Look at an AMT like one of the Beymas.

I think this comes to personal preference

I have tried a few types of tweeters myself and no matter which tweeter I have used there is always trade off.

I have this particular tweeter running now and would argue that it would not keep up with any system but again it comes to personal taste.

I took several measurements of this tweeter -+ 2db 1000hz-30000hz

SCAN SPEAK Revelator D2908/714000

 

 

 

 

 

Edited July 21, 2017 by jkn

[jkn]

On 20/07/2017 at 0:54 PM, A9X said:

Confession; never heard a dome I really like. And in my opinion, it will not keep up with the rest of the system and will definitely be it's limitation. Look at an AMT like one of the Beymas.

 

I had a look at the AMT (beyma)  drivers they look good >I might order a pair as I never hear AMT's

 

[A9X]

The Beymas are the ones I've heard the most, but there are some Aurum Cantus units that look and measure well too. The horns.pl guys have also done a waveguide for them but I've yet to see or price one.

[joz]

Love your idea Jiri.

But hey, rather than a pair of PHL 18s/side, I wouls suggest one of the 18s/side being a sub.

 

You've gone 4 way may aswell go 5 and get some plummeting bass while your there.

Now If In was going to do mine again I would do something like yours but as  a 5 way as suggested

[jkn]

5 hours ago, A9X said:

The Beymas are the ones I've heard the most, but there are some Aurum Cantus units that look and measure well too. The horns.pl guys have also done a waveguide for them but I've yet to see or price one.

Thanks for info. I also had a look at mundorf  but they are getting expensive at least those few hi end version.

Edited August 2, 2017 by jkn

[jkn]

4 hours ago, joz said:

Love your idea Jiri.

But hey, rather than a pair of PHL 18s/side, I wouls suggest one of the 18s/side being a sub.

 

Hi Joz

I have tried all kind of  variation possible but not with much luck (I do have all 4 18"here)

5 hours ago, joz said:

You've gone 4 way may aswell go 5 and get some plummeting bass while your there.

Now If In was going to do mine again I would do something like yours but as  a 5 way as suggested

I have to say that 5 way never work for me.

Last 6 months I have been playing with 5 way and I always go back to 4 way.

 

Just for example the way I have my main PHL 18 setup in the room they hardly measure lower then 45hz that is with minimal correction ( 6db boost)  but the bass is really nice and tight .

Now if I put them in the corners they will measure down to 25hz. (but not as clean/tight ) 

Since I had 4 PHL or other drivers on hand I went 5 way but there is obviously more  cor_filters >more delays (20ms +)  and so on so switching between  4 and 5 way on the remote  makes 4 way much better > the downside is the bass extension.

 

In regards of my propose design above I have change my mind and will do simpler set >

18" PHL (on the bottom) 

6.5" midrange

Tweeter (not sure which yet)

6.5" midrange

10" (on the Top)

I'm using this combination (except of the 10" I only have 9")  and I really enjoy it.
interestingly I always go back to place the mid/bass on the top of the tower to me just sounds much better> like Focal utopia driver arrangement