15in + CD - hifi 2way - low power - woofer explorations

[daemonsgr]

Hi all,
For a while now Ive been going through all available thread about 2way 15in (and maybe 3way) systems.
The utlimate plan is to build one 2way for me with WAF approved cabinet , so CNC curvy and slim to crate the illusion of less volume, and for a friend without a WAF a lascala bassbin with the extra BR under it (not referred in the thread).

Im looking for efficiency as I want to be able to power it with low watts too. 'hifi' quality as much as possible. My listening is not high SPL, usually 70 to 85? Also I always wanted to do a classic 15in+horn mainly with a 2226h.
2 channel music without a sub is the target for now.

I looked what well established people have done like: 4Pi, Calpamos and the threads here, to get ideas.

for the 2226h I started with the recommendation below to test in WinISD and I recreated 4Pi in CAD so I can measure the volume and compare with the published response graphs. (cab in the sims is C4/SC4)

For max efficiency Vs size, BW, the pioneer's reflex alignment Vas/1.44 tuned to Fs. Using published Vas, Fs, HR predicts a mean eff. from 40-200 Hz of 98.23 dB/m/2pi/89 Hz and only dropping to 97 dB with 4 ohms output impedance.

GM

So questions:
1) How does this look? I compared it to other LF drivers I see in builds here and Im not sure about the low end, I now 2226h is not a low end driver per se but its one of the popular choices for low end.
Images attached. I manipulated volume and tuning a bit on the other drives to see what I get for comparison. all around 120-135L I believe but I think Beymas need more.

2) What should I expect when seeing simulations like these? (for all I found workable BR sizes and vent speeds etc)

3) Do you consider the other options (Beyma etc) to be better for sound quality as its newer tech etc? Any other pointers? (the simulated models are 15P80feN/ND)

The HF half seems to be something like DE250/Faital201 or something.

Thanks

PS: I attached a cad or the design I thinking (internal volume without braces etc.. very draft and propably not the correct volume with the above but close to 130L clean internal) The horn is just a placeholder! Random model. I have access to super workshop/CNC so sides will be full CNC probably.

 

[AllenB]

There's a lot that looks good about it, and also considering your comments on future plans.

First time I built this style I went with ports. Then as I focused on the low end and subs, I dropped the ports. Better results, I thought. It was nothing to just block them off, the rest of the design was unchanged.

Still, I wouldn't consider the box to be overly critical. It's mostly what you end up with after all of the things you do towards better bass rather than the precision of one item.

 

[daemonsgr]

Still, I wouldn't consider the box to be overly critical. It's mostly what you end up with after all of the things you do towards better bass rather than the precision of one item.

Can you elaborate the last part a bit more?
thanks

 

[AllenB]

I was talking about bass. Small variations in alignment aren't a big deal. In some cases they can be equalised.

Then you have room variations. If I would assume that you use multiple subs, these will vary your response somewhat. After this you might do a little EQ anyway.

What I have found is that blending with subs may be easier starting with a closed box. Having the option of blocking ports or not, is probably also a good thing.

It is not such a concern for your mains to only go down to 50-70Hz or so if you are planning to use subs. It is also good for efficiency to not need a woofer with too low a Fs.

 

[daemonsgr]

I was talking about bass. Small variations in alignment aren't a big deal. In some cases they can be equalised.

Then you have room variations. If I would assume that you use multiple subs, these will vary your response somewhat. After this you might do a little EQ anyway.

What I have found is that blending with subs may be easier starting with a closed box. Having the option of blocking ports or not, is probably also a good thing.

It is not such a concern for your mains to only go down to 50-70Hz or so if you are planning to use subs. It is also good for efficiency to not need a woofer with too low a Fs.

At the moment Im not planning a sub at all. Only two channels, so the low end needs to be ok.

 

[Brett]

for the 2226h I started with the recommendation below to test in WinISD and I recreated 4Pi in CAD so I can measure the volume and compare with the published response graphs. (cab in the sims is C4/SC4)

Get the 2226 datasheet from JBL (first search response) and you'll find they tune to 40Hz in 140L net.

If you're going active then you can do 6th order ported in about 40L. I've used this alignment in my home and PA units and it's excellent. Will post more if you're interested next week.

I've owned lots of 2225/6 units and they're great.

 

[daemonsgr]

Get the 2226 datasheet from JBL (first search response) and you'll find they tune to 40Hz in 140L net.

If you're going active then you can do 6th order ported in about 40L. I've used this alignment in my home and PA units and it's excellent. Will post more if you're interested next week.

I've owned lots of 2225/6 units and they're great.

1) I'd love to know more when you have time. Im not currently fixed to the 2226h if there are other alternatives.

2) The design I aim is something like the images I had in my first post, if possible. WAF approval is needed and a 6th order box is out of the question!!

3) Im aiming for a passive system. no active XO etc.

4) the 2226h simulations are with 38hz tuning similar to the 4Pi.

so, 2 channel hifi for music and 2 way. 15 LF and CD+horn HF.
Reviewing "Beyma designs from 2008/2009" there is a 15p80nd + CP755ti that looks good.

Anyone with experience from 15P80s? or maybe comparison?
thanks

 

[1audiohack]

Hello dae;

JBL never used the 2226 in a domestic or studio monitor speaker, not even the basket motor assembly with another cone kit. Ever wonder why?

JBL has far better candidates for home especially for low power use.

From fairly inexpensive and obtainable the list goes:
2234 / 2235
2226-1
2216

The first two will tune in the low 20’s in 140 liters and require much less eq “force” to sound full and balanced.

The 2216’s are more expensive but are flat amazing. Climbing the JBL ladder further gets expensive.

I have 2226’s employed in several systems but none in the house.

Barry.

 

[daemonsgr]

Hello dae;

JBL never used the 2226 in a domestic or studio monitor speaker, not even the basket motor assembly with another cone kit. Ever wonder why?

JBL has far better candidates for home especially for low power use.

From fairly inexpensive and obtainable the list goes:
2234 / 2235
2226-1
2216

The first two will tune in the low 20’s in 140 liters and require much less eq “force” to sound full and balanced.

The 2216’s are more expensive but are flat amazing. Climbing the JBL ladder further gets expensive.

I have 2226’s employed in several systems but none in the house.

Barry.

Thank for the info. I didnt know the details.

Maybe focus on the 15P80* then? Not many builds in the forum but it seems good.

 

[Qts]

What kind of crossover frequency are you planning? Good woofer may be worse midrange. I would use EQ to help low end.

 

[daemonsgr]

Some beyma proposed configurations for example (and other posts in this forum) with the 755ti CD can do an XO at 1khz. I think the woofer like 12p80nd holds ok till 1khz right?
But generally around 1k!?! No?

Some good builds even use 1in CD. (Other 2in like the faital201)

 

[AllenB]

If you use a regular 45 degree waveguide, the crossover frequency will be set by your woofer. 15" at or below 1kHz, 12" will be above.

1" cd should work with either of these.

 

[daemonsgr]

If you use a regular 45 degree waveguide, the crossover frequency will be set by your woofer. 15" at or below 1kHz, 12" will be above.

1" cd should work with either of these.

What is a regular waveguide for example?

I was thinking a 1.4in cd with something like a RCF 90-something horn? Im open to recommendations to be honest.

 

[AllenB]

Regular would I guess be round, 45 degrees and at least the same size as the woofer. That way, its behaviour is similar at all frequencies and matches the woofer at one frequency. The horn is capable of reaching down to that frequency.

Other horns might work reasonably, some will not be as successful.

 

[daemonsgr]

Regular would I guess be round, 45 degrees and at least the same size as the woofer. That way, its behaviour is similar at all frequencies and matches the woofer at one frequency. The horn is capable of reaching down to that frequency.

Other horns might work reasonably, some will not be as successful.

Got it! Thanks.

I could probably CNC a round one to test. Even though they tend to be thick and bulky for construction reasons.
I need to model something in 3d and see.

Of the shelf one I read good things about RCF 950 for example.

 

[AllenB]

Some also mention the 18sound XT1464. In fairness, the result is probably not that bad. I mean, the first waveguide I bought was the Dayton 8" pictured. It was a flimsy screw in type, but it sounded very good. Once I became accustomed to the sound and made measurements I found that it wasn't performing low enough or matching well with the woofer. So I began to make my own.

 

[mayhem13]

Go with a 1” CD if it’s truly a low power home use design......the 1.4” beam too early for my taste and lock you in to a smaller listening position......or instead go three way with a 2”CD and a super tweeter.........that’s what I do now as my ears (and most of us who live in reality past 40) don’t resolve ragged content above 10khz....as long as it’s there for a sense of presence or air. I mount it on the same baffle as the 15” above the driver, below the horn. I prefer slotted for wide horizontal dispersion.

 

[daemonsgr]

Go with a 1” CD if it’s truly a low power home use design......the 1.4” beam too early for my taste and lock you in to a smaller listening position......or instead go three way with a 2”CD and a super tweeter.........that’s what I do now as my ears (and most of us who live in reality past 40) don’t resolve ragged content above 10khz....as long as it’s there for a sense of presence or air. I mount it on the same baffle as the 15” above the driver, below the horn. I prefer slotted for wide horizontal dispersion.

There are some nice looking RCF 1.4in horns that seem to have a good angle.
Ive seen recommendations for them in another post.
Maybe a FaitalPro 1.4in + a horn like this crossed @1k with a 2226h? or Bayma 15p80nd?

 

[AllenB]

The more you choose a narrow angle, the more its size becomes a limitation. You will end up with narrow highs and wide upper mids. For this reason a short vertical will overtake a wider horizontal and flip the pattern.

I'm not suggesting you use something like the Dayton I showed above, but understand, that it makes best use of the space it takes up and It doesn't try to start holding a directivity that it can't finish. Instead it hands off continuously within its limits.

 

[chris661]

There are some nice looking RCF 1.4in horns that seem to have a good angle.
Ive seen recommendations for them in another post.
Maybe a FaitalPro 1.4in + a horn like this crossed @1k with a 2226h? or Bayma 15p80nd?

If this is for home use, you'll get away with running the compression drivers nice and low. I'd be confident in running a 3" diaphragm down to 600Hz, so long as the crossover is reasonably steep.

I use an 18Sound ND1460 on an RCF HF94 per side for my PA system. Crossover is usually in the 800Hz range, as that provides the best directivity match to the 2x10" midbass drivers. For high-power use*, I take the crossover up to 1.2kHz.

* See - YouTube

Chris