Help tuning my FE127e fullrange ref MLTL

dublin78 · 2nd April 2008, 11:28 AM

I have recently completeted a pair of Diyaudio fullrange reference MLTL monopoles.

I am not blown away by them, and I am wondering what the fuss is about fullrange loudspeakers. Maybe they need tuning?

See photos.

I have lined the cabinets with traditional felt (10mm est) on the rear of the cabinets, and synthetic felt (2x5mm est) on the fronts. I have stuffed the top 3/4 of the cabs with three layers of MDM3.

I have made the vents 50.8 mm long x 51mm diameter.

Ouch. ****, ^^^^, """", !!!!!!!!. I have just noticed from the original drawings that the monopoles should be 38.1 diameter. This is very annoying as I spent hours cutting the holes to 51mm (dipole diameter) with about 20 sessions each using a specially purchased Forstner bit. The idea was to avoid plastic tubes.

Is this likely to be responsible for the muddy sound?

The top end is good.

chrisb · 2nd April 2008, 04:09 PM

ouch, that is a lot of time & materials to invest in a project that leaves you underwhelmed.

As best as I can recall, there were many variations on enclosure dimensions, driver placement & vent tuning this series. Of the few that I built or heard, my personal favorites were the folded monopole which I made into a short, angled floorstander for my mom, and Scott Dunn's bipoles.

Yes, if your port is oversized, the tuning will definitely be off. How are these mounted? If the vent is downfiring, you could possibly line the inside of the port with a cut length of ABS pipe, hot glued in place - out of sight, etc......

SCD · 2nd April 2008, 04:32 PM

Yes you have a bit of a pickle here.
I was thinking the same thing as Chris. A liner to reduce the tuning diameter of the port will solve the problem.
Another thought once you get that dimeter solved is how is the port loaded I have a sneaking suspicion that the presentation does not load the floor or a wall. If this is the case the bass might be a little thin.

Also these speakers do like a current source more than a voltage source. Nelson Pass has a good paper on this topic that is worth the read. A Tube amp or an F4 ( or other current source) are quite wonderful. There are other amps that perform quite well, these are the ones I know about.

Good luck

dublin78 · 2nd April 2008, 04:43 PM

These are designed to be wall mounted with the port facing down.

I have already been to the plumbing shop today, but it was closed.

I will insert a piece of pipe of the correct length and internal diameter and fill the gaps with silicone, and report back.

Perhaps we can get on with tuning after that.

SCD. these are to be used with my digital amp based system, see below. there is a pair of subs to follow.

DIYPARADISE CD63 based "music centre"

chrisb · 2nd April 2008, 05:00 PM

Once you get the tuning / installation kinks worked out, I'd think it very likely you'll understand what the "FR" fuss is all about.

GM · 2nd April 2008, 09:23 PM

Hmm, it's a bit late, but I calc'd an alternate driver position if anyone's interested, though with such small cabs it's debatable as to how audible the difference might be:

Monopole: 11.09"
Bipole: 12.09"

One thing's for sure though, even wall mounted the monopole will still probably need some BSC at this low tuning (for the driver).

GM

dublin78 · 7th April 2008, 02:53 PM

http://www.diyaudio.com/forums/attac...amp=1102456925

I am struggling to find some pvc or similar tube with 38mm (1.5")internal diameter. 35mm is the nearest in the UK, so far.

Should I keep looking, or adjust the length accordingly. If so please could someone do the calculation for me (with 35mm tube) or point me to the software, so that I can have a go myself.

G · 7th April 2008, 10:55 PM

Quote:

Originally posted by dublin78
http://www.diyaudio.com/forums/attac...amp=1102456925

I am struggling to find some pvc or similar tube with 38mm (1.5")internal diameter. 35mm is the nearest in the UK, so far.

Should I keep looking, or adjust the length accordingly. If so please could someone do the calculation for me (with 35mm tube) or point me to the software, so that I can have a go myself.

Just adjust the length. All you are doing is looking for the correct volume of the tube. If the diameter is narrower then make the length longer. Look for a volume calculator on the web that calculates the volume of a cylinder.

GM · 8th April 2008, 01:39 AM

Hmm, it's not about matching the vent's volume. For a given Fb, a smaller diameter vent requires a shorter one.

Anyway, RonE has periodically posted a vent scaling solution:

L2 = L1*(D2^2/D1^2), where D2 is new the diameter and D1 is the original diameter.

GM

planet10 · 8th April 2008, 05:35 AM

I have a pair of the diyRef bipoles (in the mezzanine)... i find them a bit tubby in the bass, but this often seems to happen when you try to max the bass with a small FR.

I REALLY enjoy them as fronts for the HT.

dave

2nd April 2008, 11:28 AM	#1
dublin78 diyAudio Member Join Date: Mar 2006 Location: Cheshire	Help tuning my FE127e fullrange ref MLTL I have recently completeted a pair of Diyaudio fullrange reference MLTL monopoles. I am not blown away by them, and I am wondering what the fuss is about fullrange loudspeakers. Maybe they need tuning? See photos. I have lined the cabinets with traditional felt (10mm est) on the rear of the cabinets, and synthetic felt (2x5mm est) on the fronts. I have stuffed the top 3/4 of the cabs with three layers of MDM3. I have made the vents 50.8 mm long x 51mm diameter. Ouch. ****, ^^^^, """", !!!!!!!!. I have just noticed from the original drawings that the monopoles should be 38.1 diameter. This is very annoying as I spent hours cutting the holes to 51mm (dipole diameter) with about 20 sessions each using a specially purchased Forstner bit. The idea was to avoid plastic tubes. Is this likely to be responsible for the muddy sound? The top end is good.

2nd April 2008, 04:09 PM	#2
chrisb diyAudio Member Join Date: Aug 2002 Location: victoria BC	ouch, that is a lot of time & materials to invest in a project that leaves you underwhelmed. As best as I can recall, there were many variations on enclosure dimensions, driver placement & vent tuning this series. Of the few that I built or heard, my personal favorites were the folded monopole which I made into a short, angled floorstander for my mom, and Scott Dunn's bipoles. Yes, if your port is oversized, the tuning will definitely be off. How are these mounted? If the vent is downfiring, you could possibly line the inside of the port with a cut length of ABS pipe, hot glued in place - out of sight, etc...... __________________ you don't really believe everything you think, do you? community sites t-linespeakers.org, frugal-horn.com commercial site planet10-HiFi

2nd April 2008, 04:32 PM	#3
SCD diyAudio Member Join Date: Nov 2003 Location: 1/2 way up Vancouver Island	Your hole is too big! Yes you have a bit of a pickle here. I was thinking the same thing as Chris. A liner to reduce the tuning diameter of the port will solve the problem. Another thought once you get that dimeter solved is how is the port loaded I have a sneaking suspicion that the presentation does not load the floor or a wall. If this is the case the bass might be a little thin. Also these speakers do like a current source more than a voltage source. Nelson Pass has a good paper on this topic that is worth the read. A Tube amp or an F4 ( or other current source) are quite wonderful. There are other amps that perform quite well, these are the ones I know about. Good luck __________________ SCD

2nd April 2008, 05:00 PM	#5
chrisb diyAudio Member Join Date: Aug 2002 Location: victoria BC	Once you get the tuning / installation kinks worked out, I'd think it very likely you'll understand what the "FR" fuss is all about. __________________ you don't really believe everything you think, do you? community sites t-linespeakers.org, frugal-horn.com commercial site planet10-HiFi

2nd April 2008, 09:23 PM	#6
GM diyAudio Member Join Date: Jun 2003 Location: Chamblee, Ga.	Hmm, it's a bit late, but I calc'd an alternate driver position if anyone's interested, though with such small cabs it's debatable as to how audible the difference might be: Monopole: 11.09" Bipole: 12.09" One thing's for sure though, even wall mounted the monopole will still probably need some BSC at this low tuning (for the driver). GM __________________ Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.


	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

2nd April 2008, 04:43 PM	#4
dublin78 diyAudio Member Join Date: Mar 2006 Location: Cheshire	These are designed to be wall mounted with the port facing down. I have already been to the plumbing shop today, but it was closed. I will insert a piece of pipe of the correct length and internal diameter and fill the gaps with silicone, and report back. Perhaps we can get on with tuning after that. SCD. these are to be used with my digital amp based system, see below. there is a pair of subs to follow. DIYPARADISE CD63 based "music centre"

7th April 2008, 02:53 PM	#7
dublin78 diyAudio Member Join Date: Mar 2006 Location: Cheshire	http://www.diyaudio.com/forums/attac...amp=1102456925 I am struggling to find some pvc or similar tube with 38mm (1.5")internal diameter. 35mm is the nearest in the UK, so far. Should I keep looking, or adjust the length accordingly. If so please could someone do the calculation for me (with 35mm tube) or point me to the software, so that I can have a go myself.

8th April 2008, 01:39 AM	#9
GM diyAudio Member Join Date: Jun 2003 Location: Chamblee, Ga.	Hmm, it's not about matching the vent's volume. For a given Fb, a smaller diameter vent requires a shorter one. Anyway, RonE has periodically posted a vent scaling solution: L2 = L1*(D2^2/D1^2), where D2 is new the diameter and D1 is the original diameter. GM __________________ Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

8th April 2008, 05:35 AM	#10
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	I have a pair of the diyRef bipoles (in the mezzanine)... i find them a bit tubby in the bass, but this often seems to happen when you try to max the bass with a small FR. I REALLY enjoy them as fronts for the HT. dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Box for the FE127e	despotic931	Full Range	18	11th November 2008 12:46 AM
Tuning port on MLTL : how ?	sadhill	Full Range	7	8th October 2008 07:43 PM
GM MLTL fine tuning	loninappleton	Full Range	35	17th April 2008 07:31 PM
MLTL port tuning	Josephjcole	Full Range	9	4th August 2005 01:22 PM
FE127E in small hardwood MLTL	johninCR	Multi-Way	6	28th March 2005 07:19 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read