Help with Lowther Dx3 open baffle

kinku · « **on:** 30 Dec 2016, 12:07 am »

Hi,
I am in the planning phase of an OB full range system with DX3 drivers I own.
I have not decided on my woofers yet.
I have read some articles about them and specifically from Quarter wave website.
It seems like I need to use active crossover and bi amp to achieve good results( expecting a low end at 30-40Hz).
Hope to hear from you about recommendations and some plan ideas.
PS: not looking for a huge baffle if possible.

Scott F. · « **Reply #1 on:** 30 Dec 2016, 01:52 am »

In my opinion, you definitely need an active XO to do Lowthers. Here is an article I wrote some time back about a narrow baffled Lowther for ETM.

http://www.enjoythemusic.com/magazine/equipment/1009/lowther_high_efficiency.htm

Even though I've drastically changed my system, that was the best, most accurate system that I've ever experienced.

If you use my article as a guide, you won't go wrong.

Enjoy the journey

Blackmore · « **Reply #2 on:** 30 Dec 2016, 02:04 am »

+1 on Scott's approach. You'll get some great results.

ebag4 · « **Reply #3 on:** 30 Dec 2016, 02:14 am »

Hard to believe that was 8 years ago.

Best,
Ed

Scott F. · « **Reply #4 on:** 30 Dec 2016, 02:54 am »

Quote from: ebag4 on 30 Dec 2016, 02:14 am

Hard to believe that was 8 years ago.

Best,
Ed

Hiya Ed

I know. Guess we're all getting old. Lord knows I feel it these days

kinku · « **Reply #5 on:** 30 Dec 2016, 04:35 am »

Thanks Scott. I thought it was for PM2a.

Scott F. · « **Reply #6 on:** 30 Dec 2016, 01:03 pm »

As I mentioned in the article, other Lowther drivers should work in the offset baffle as most of them have have a peak at 2.5k. I've seen that a few guys around here and around the web have build them using drivers other than the PM series.

You'll find that offset baffle really changes the character of the DX drivers and smooths them out.

kinku · « **Reply #7 on:** 30 Dec 2016, 04:57 pm »

Scott. What are you woofer recommendations. Eminence Alpha 15 seems promising. Alter 416 is tough to source .
How accurate is simulation with Basta? Don't know if MJK still offering his work sheets?

nicoch · « **Reply #8 on:** 8 Jan 2017, 11:47 am »

Nelson Pass made nice system http://www.diyaudio.com/forums/multi-way/195734-nelson-pass-slot-loaded-open-baffle-project.html
there is an evolution too

JohnH12 · « **Reply #9 on:** 9 Jan 2017, 12:46 am »

Quote from: kinku on 30 Dec 2016, 04:57 pm

Scott. What are you woofer recommendations. Eminence Alpha 15 seems promising. Alter 416 is tough to source .
How accurate is simulation with Basta? Don't know if MJK still offering his work sheets?

ABC Dipole will give decent simulations based on TS parms. If you can trace the frequency response and get a FRD file you can added it to Edge baffle response.

The Eminence is good if you want to do a passive system. The decision imo should be amplified/ DSP or passive then you can pick woofers.

kinku · « **Reply #10 on:** 9 Jan 2017, 03:11 am »

John ,does that mean alpha 15A not good for active design.I am planning to do it with Minidsp HD and bi amp.

JohnH12 · « **Reply #11 on:** 10 Jan 2017, 03:07 am »

The Em Alpha has limited x-max so you will run out volume in the lower frequencies.

ABC Dipole is free http://www.musicanddesign.com/A_B_C_Dipole.html The help file is very good.

or you can use spl_max from Linkwitz on this page http://www.linkwitzlab.com/thor-estim.htm

If you can bi amp then look for a large woofer with a low FS and high x-max. If you are doing a two way look for a woofer that can play up to about 700 Hz if you are doing a full ranger on top. That means some subwoofers will not make the cut.

Poultrygeist · « **Reply #12 on:** 10 Jan 2017, 12:18 pm »

Technically an active worked well for my DX3 crossed over to double Alphas but I lost some of the SET magic in the process. I love the DX3 running full range with nothing in the signal path and these days I just bring in the Alphas with a plate amp to fill in the low end. My preference is probably colored by the fact that I rarely listen to anything other than small group jazz at low levels so I don't need woofers with strong bass.

nicoch · « **Reply #13 on:** 10 Jan 2017, 12:41 pm »

Poultrygeist you can do a nice trick ,change the coupling caps on set amp to lower value, just to cut some bass ,your output iron and the dx3 will be more happy

kinku · « **Reply #14 on:** 12 Jan 2017, 07:05 pm »

Poultrygiest is it possible to publish your open baffles width and height along with driver positions here. I will create a cad file for everyone interested.Perhaps someone can help run simulations too.

Poultrygeist · « **Reply #15 on:** 12 Jan 2017, 09:54 pm »

Mine are approximately 48" x 20" and I followed MJK's guidelines for woofer and off set driver locations.

kinku · « **Reply #16 on:** 13 Jan 2017, 02:43 am »

Please do explain if it is possible what are the guidelines by MJK

nicoch · « **Reply #17 on:** 13 Jan 2017, 09:30 am »

www.quarter-wave.com/OBs/OB_Design.pdf

kinku · « **Reply #18 on:** 13 Jan 2017, 10:10 am »

Nicoch,This is for a Fostex driver with single woofer .

MJK · « **Reply #19 on:** 14 Jan 2017, 03:13 pm »

Two options :

Traditional FR - W - W arrangement

http://www.quarter-wave.com/OB_3_Drivers_Corner_Passive_DX3_2 x Alpha 15A_1_14_17.pdf

Currently popular W - FR - W arrangement

http://www.quarter-wave.com/OB_3_Drivers_Corner_Passive_Alpha 15A_DX3_Alpha 15A.pdf