Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Woofer or Compression Driver Handling the Midrange?
Woofer or Compression Driver Handling the Midrange?
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 5th September 2013, 03:34 PM   #1
jamesdb is offline jamesdb  United States
diyAudio Member
 
Join Date: Jun 2007
Default Woofer or Compression Driver Handling the Midrange?

Say you had a 1.5 watt 45 SET tube amp, and were planning a high efficiency speaker like the Econowave or SEOS designs, using a 15” woofer & compression driver, aiming for a woofer that was rated at least 100dB. Assume one of the woofers that have a frequency range that is rated up to 4KHz, 4.2 or 4.8KHz. Size & WAF not an issue but high sensitivity is.
Is it better to have a high crossover point at 3.5 KHz where the 15” driver is reproducing most of the midrange around 1k-4k? Here the benefit is the midrange would not be attenuated.
Or is it better to have a low crossover like at 900Hz, 1KHz or 1.6KHz where the compression driver is handling most of the midrange between 1k-4k? But that usually means the midrange is being attenuated, as most compression drivers need 5-10dB of attenuation to match the woofer.
I am mainly wondering if it sounds better to have the midrange reproduced by the compression driver, even if it needs several dB of attenuation, from those who have experience.
Or since the speaker would be used with a 1.5W SET, should a focus be on matching a drivers so no attenuation is needed, regardless of where the crossover would be? if the woofer and compression driver did match in sensitivity and did not require any attenuation, would it be most people’s preference to choose a crossover point that had the woofer or compression driver reproducing the midrange? Thanks for any input.
  Reply With Quote
Old 5th September 2013, 04:38 PM   #2
Cal Weldon is offline Cal Weldon  Canada
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: Near Vancouver
Woofer or Compression Driver Handling the Midrange?
Before we try and explain, you might want to read up on beaming and cone break up. Once you understand those two it will give you a better idea of what compromises you are willing to accept. The combo you are proposing is more suited to PA duty than critical listening for reasons you will come to understand. After that, come back and ask questions.

Cheers.
  Reply With Quote
Old 5th September 2013, 05:25 PM   #3
POOH is offline POOH  United States
diyAudio Member
 
POOH's Avatar
 
Join Date: Oct 2010
Location: Ohio
With a single ended 45 amp and not biamping you should consider a 2-way horn with a 10 or 12" bass driver loaded in a front hypex or expo horn and either a 1.5 or 1" compression driver crossed over between 500 and 800 cycles. A compression tweeter may be added to add to the top end and subwoofers for the low bass. Fully horn loaded you may actually have enough head room in the system to be satisfied with the 45 output tube.
  Reply With Quote
Old 5th September 2013, 10:27 PM   #4
BlueWizard is offline BlueWizard  United States
diyAudio Member
 
Join Date: Jun 2007
Sorry to say it this way but -

If ducks were gorillas would it be better to feed them bananas or bread crumbs?

Well the answer is, it doesn't matter because Duck are NOT Gorillas, and you do not, at least not very likely, have a 15 woofer that is functional to 4khz or more.

Yes, the frequency response might be rated at 4khz (or more) but that does not mean that is within the practical working range of the woofer. Few woofer, even must smaller woofer, are functional above 2khz or there about. And the preferred functioning range is probably around 1khz or less.

Next, a hypothetical woofer and a hypothetical compression driver are capable of 500db, and any crossover. But fantasy is not reality.

As to the midrange/highs being attenuated, they are only attenuated, in my understanding, to bring them down to the level of the woofer. So, I'm not clear on what you mean here.

The only meaningful response can be relative to real drivers. Tell use what drivers you are considering and give us a better idea of the application, and those here in-the-know, can response with something you can actually use.

Or, explain your project requirements and use in detail, and likely someone here knows of a good project to fill those requirements.

I see no point in speculating on hypothetical fantasy because those fantasies are never going to translate into reality. Far better for focus on reality, because that will lead to actual reality when translated into a speaker.

The general rule is - let each driver do what it does best.

So -

- Either give us an example with real drivers, or potential drivers, under consideration.

- Or, give us the details on the design concept, and let the members here recommend speakers and/or projects that fill those requirements.

But then ... that's just my opinion.

Steve/bluewizard

Last edited by BlueWizard; 5th September 2013 at 10:30 PM.
  Reply With Quote
Old 5th September 2013, 11:48 PM   #5
jamesdb is offline jamesdb  United States
diyAudio Member
 
Join Date: Jun 2007
Thanks for the responses so far. Mainly I am interested in building a pair of DIY speakers that would have the sensitivity a 1.5 watt SET tube amp would require. From what I gather that would be around 100dB or even more. Trying to sort through the many DIY plans has taken a lot of reading. I am not committed to any specific speaker type and could use some help narrowing down a list of projects that may already exist that I am not aware of. It would be for music, critical listening/home audio use, not home theater user, budget around $700 or thereabouts, max $1,000.
  Reply With Quote
Old 6th September 2013, 01:05 AM   #6
whgeiger is offline whgeiger  United States
diyAudio Member
 
Join Date: May 2004
Location: Pensacola, Florida
Default Neither, Some Horn Magic is Needed

Quote:
Originally Posted by jamesdb View Post
Say you had a 1.5 watt 45 SET tube amp, and were planning a high efficiency speaker like the Econowave or SEOS designs, using a 15” woofer & compression driver, aiming for a woofer that was rated at least 100dB. Assume one of the woofers that have a frequency range that is rated up to 4KHz, 4.2 or 4.8KHz. Size & WAF not an issue but high sensitivity is.
Is it better to have a high crossover point at 3.5 KHz where the 15” driver is reproducing most of the midrange around 1k-4k? Here the benefit is the midrange would not be attenuated.
Or is it better to have a low crossover like at 900Hz, 1KHz or 1.6KHz where the compression driver is handling most of the midrange between 1k-4k? But that usually means the midrange is being attenuated, as most compression drivers need 5-10dB of attenuation to match the woofer.
I am mainly wondering if it sounds better to have the midrange reproduced by the compression driver, even if it needs several dB of attenuation, from those who have experience.
Or since the speaker would be used with a 1.5W SET, should a focus be on matching a drivers so no attenuation is needed, regardless of where the crossover would be? if the woofer and compression driver did match in sensitivity and did not require any attenuation, would it be most people’s preference to choose a crossover point that had the woofer or compression driver reproducing the midrange? Thanks for any input.
Horn Loaded (Compression) driver design trades bandwidth for efficiency.

If you choose to use wimpy amps then an all-horn system will meet mission requirements, but it will need to be 3-way.

Strangly, the midrange will be the biggest challange.
Idealy you do not want to carve up the speach range. 200-300 Hz to 2,000-3,000 Hz.

Use the set amp you have for the top end only.

Regards,

WHG
  Reply With Quote
Old 6th September 2013, 01:12 AM   #7
jamesdb is offline jamesdb  United States
diyAudio Member
 
Join Date: Jun 2007
My budget of $700 is for drivers, not including cabinet wood/binding posts. Here is one combination I was looking at. The EighteenSound 15MB700 15" woofer Eighteen Sound Speakers - 18 Sound - Eighteen Sound 15MB700 - Eighteen Sound 15MB700 15" midbass 400 watt AES speaker. Eighteen Sound 15MB700 midbass speakers are available here. 18 Sound speaker components. and the Celestion CDX1-1415 compression driver Celestion CDX1-1415 Neo 1" Compression Driver 20W 294-2130 with crossover at 2.5K. An alternate compression driver would be the Dayton Audio D250-P Dayton Audio D250P-8 1" Polyimide Compression Horn Driver 270-402 as both the compression drivers are rated at 104dB while the woofer is 103dB. I was thinking a tube amp would benefit from no attenuation matching this way. Also I have a powered subwoofer that could be added in at 150Hz if a two way speaker were designed with the components above.
  Reply With Quote
Old 6th September 2013, 01:57 AM   #8
DougL is offline DougL  United States
diyAudio Member
 
Join Date: Feb 2004
Location: Wheaton IL.
Sadly,
The woofer you linked to will not be 103 dB in a box.
At some frequency, it will become somewhere between 97 and 100 dB because of "baffle step". So you are going to have to pad your tweeter down between 4 and 7 dB to compensate, or put up with the thin base response.
You can actually see it on the frequency response chart the manufacture provides.
Notice how it slops down starting at 300 Hz?

HTH

Doug
__________________
Scienta sine ars nihil est - Science without Art is nothing. (Implies the converse as well)
Mater tua criceta fuit, et pater tuo redoluit bacarum sambucus
  Reply With Quote
Old 6th September 2013, 02:18 AM   #9
BlueWizard is offline BlueWizard  United States
diyAudio Member
 
Join Date: Jun 2007
We know more, but I still don't think you are providing sufficient context.

First -

WHY?

Why this particular combination? Why only a 1.5w amp?

Most speakers, in general, can be driver to 90dB with about 1 watt, however, to drive the same speaker to 93dB takes 2 watts, and to 96dB takes 4 watts, and 99dB takes 8 watts. To reach 102dB takes 16 watts.

Next, while certainly not impossible, you will have a hard time finding a woofer with 100dB output. At least not a Sensitivity rating.

Next, do you expect to sustain 100dB or just peak at 100dB?

My speaker are rated at 90dB, I have no problem reaching 100dB peaks and above, but I'm using a 100w/ch amp with speakers that have 2x 8" woofers each.

If you are going for ultra-high output on the bass driver, then you are likely going to need a front horn load, horn loaded port, of a large transmission line design.

The Eighteen Sound Woofer linked to by JamesDB has the output you need, but they are $500 per pair. That is half your budget, and you don't have mid, high, crossovers, cabinets, or misc components.

To get the efficiency from the woofer though, you are going to need a pretty large cabinet. Do you have room for such a cabinet.

Just to give you an idea of the size speaker we are talking about, take a look at these for inspiration -

Everest DD67000 Floorstanding Loudspeaker | JBL Synthesis

Everest DD65000 Floorstanding Loudspeaker | JBL Synthesis

S3900 Floorstanding Speaker | JBL Synthesis

K2 S9900 Floorstanding Speaker | JBL Synthesis

The twin bass driver 3-way models (DD6700) have 96dB/1w/1m, where as the single bass driver model (K2 S9900) has 93dB/1w/1m. (1 watt at 1 meter)

If you don't just want peaks in the +100dB range, if you actually want to sustain that level, then you are going to need some very large speakers indeed.

But also consider, that if you are cruising in the 85dB to 90dB range with peaks in the roughly 100dB range, you are pretty loud. For me, I might hit that during an Action Movie, but that is way too loud for music.

Next, 100dB at the speaker is very different than 100dB at the prime seating location. If I recall correctly, the sound level drops by 6dB every time the distance between the speaker and the listener doubles. So, 100dB at your seat, probably means 110dB at the speaker. But again, that is near a painfully loud level. 90dB is far more realistic.

So, again, it depends on what you mean by 100dB in the functional sense.

Just a thought.

Steve/bluewizard
  Reply With Quote
Old 6th September 2013, 02:24 AM   #10
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: SW Florida
Woofer or Compression Driver Handling the Midrange?
In basic, practical terms - you can do pretty well with a SET 45 driving a 15" + horn. Alright for most listening in a reasonable room. I've heard it done in a large room. With a horn as wide as the cabinet, say 17-18" you can cross at 1600Hz no problem. You just want a woofer that is comfortable up there. The old Altec 515 or 416 are my personal choice, but there may be modern drivers that can do as well. I've heard some of the Celestion neo drivers with polymer 'frams and they are very nice indeed. Have not heard the model you listed.

Not sure you can do it for $700, tho.
__________________
Take the Speaker Voltage Test!
  Reply With Quote

Reply


Woofer or Compression Driver Handling the Midrange?Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
a > 150hz lower midrange Field coil compression driver, how would it look like ? angeloitacare Multi-Way 2 29th June 2012 02:01 AM
Huge 2-way with 18" woofer and 2" exit compression driver? BHTX Multi-Way 15 23rd June 2011 10:59 AM
Most rugged midrange compression driver BillyDoc Parts 39 30th June 2010 03:29 PM
woofer - compression driver matching zobsky Multi-Way 4 22nd July 2006 06:22 PM
Distance between Woofer and Midrange driver LageB Multi-Way 9 21st August 2003 05:53 AM


New To Site? Need Help?

All times are GMT. The time now is 11:26 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki