• Hello and Welcome to HiFiVision.com - an online community for the home entertainment and tech enthusiasts!

    If you would like to ask a question, participate in a discussion and view attachments please Register yourself.

Frugel-Horn 3 with Alpair 7p

Home Theatre Systems

Vivek Rao

Active Member
Joined
Nov 19, 2009
Messages
193
Points
43
Location
bangalore
For quite a long time I have been looking out for options to connect to my Shanling MC30 - 3 watt tube all in one (including an excellent FM radio !). I have this set in a separate AV room. I have been using them with my Jamo Concert 803 bookshelves for sometime now until Soundsgreat turned up and suggested to move the Jamos out to the main living room - a great decision indeed. Which meant I had to move in the Monitor Audio RX6s which were too much for my small room. Hence I had to take a call - which I did - to move to the FH3 based solution.

As a first step I had to make space and hence the RX6s sadly had to go... These were indeed fine speakers and I am so happy that they have found a new home.

Considering that I had a low power tube amp I chose the Mark Audio Alpair 7p with the paper cone as the SPLs were slightly higher as against the 7.3s. On the flip side there are really very few FHs with the newer 7ps. I am still unsure if the 87.5 db of the 7p is sufficient for my tubes...

The Build planning :
Speakers - were sourced from abroad.
FH cabinet - I wanted to use Plywood as this is what is considered best in the DIYforum for the FH.. Unfortunately in the Indian context I have found that even waterproof boards tend to warp a bit when subjected to variations in temperature... I have seen this even in my greenply boards based cupboard doors which are closest to the window. Hence against my will I chose the MDF board. I decided on a 17 mm board thickness as adequate - on actual measurement it worked out to 16.6 mm. Hence had to redo the drawings to suit these dimensions taking care that the internal geometry remained unchanged. To ensure experimentation (speaker changes, damping loading variations I decided on a top removable design - using a rubber gasket for sealing)

For the cutting I decided to go the cheapest but most precise way - so no CNC cutting but machine cutting of larger pieces and then all cutting, contouring, routing and drilling by yours truely..was economical (CNC ~ 250 Rs / sft while machine cutting Rs.250 for the entire cutting)

Tools and adhesives :
Table saw, jig saw, angle grinder with sand paper disk, router and drilling machine, plastic heat gun, Fevicol SH, SR 998. NO nails/screws - good filter masks (a must)
Since I did not have F clamps I thought on a simpler clamping setup - two flat scrap wood pieces held by long bolts (the kind they use for false roofing). Can be seen in the photos.

The build :
Sourcing the material was material was the easier part. Since all the wood work was to be done by me it took me a better part of 2 complete weekends to reach to a stage as seen in the photo.
Started with the side panels - straight cuts and jigsaw cuts for the curved contour. the curve itself was made using a template tracing the radius - my son helped out here !
The 140 mm straight panels were next cut to the lengths and ends finished to suit the 5 deg incline.
One panel was kept unstuck until I had placed all the damping pads in position.

For the speaker hole I had to improvise with my router by building a jig - can be seen in one of the photos. The hole and the countersink for the speaker ring came out really well. Had to do a bit of sanding and fine tweeking to get it precisely right.

Sourcing the felt pad was tricky - its available in large industrial stores (Rs.1000+ / kg) but I felt it was too dense... scouting around it occurred to me that a good thick cotton carpet could do the trick. The corner carpet sale shop with seconds carpets selling by the Kg helped as I could choose from a variety of carpets on sale there).
The wooden panels were held together with the clamping setup and i double lined the joints with fevicol mixed with MDF dust. After some rounds of sanding and cleaning I could put in the speaker connectors and fit the speakers.
To hold the damping material below the speakers I attached a thin plastic net (the kind used to hold vegetables in super markets) by hotglueing to the sides.

The damping filling was using Recron from a pillow - weighted out 30 g for front and 40 for the rear filling for each speaker.

Status :
The setup is under drying and the speakers are running in.

It does feel so nice to hear them after all the hard work (ah my sore back...).
Incredibly I could not sleep properly until the project was finished and the setup running..dunno if it was the back pain or the excitement .....hmm perhaps both... :)
Its amazing to hear the lows coming out of such a small speaker. I simply cannot see the diaphrams move ! (anyhow I am running at low volumes during running in so...). Everything seems so refined and clear...

Its too premature to comment further on the sound until the speakers run in and perhaps some damping optimisation done....

Hope this helps other forum members go the DIY way...
 

Attachments

  • IMG_20161217_103342.jpg
    IMG_20161217_103342.jpg
    7.3 KB · Views: 392
  • IMG_20161217_151630.jpg
    IMG_20161217_151630.jpg
    7.8 KB · Views: 391
  • IMG_20161217_173146.jpg
    IMG_20161217_173146.jpg
    10.2 KB · Views: 393
  • IMG_20161218_153925.jpg
    IMG_20161218_153925.jpg
    10.8 KB · Views: 394
  • IMG_20161225_184752.jpg
    IMG_20161225_184752.jpg
    7.2 KB · Views: 397
  • IMG_20161223_071914.jpg
    IMG_20161223_071914.jpg
    5.4 KB · Views: 400

sadik

Well-Known Member
Joined
Jun 14, 2015
Messages
908
Points
93
Location
Vadodara
Since I did not have F clamps I thought on a simpler clamping setup - two flat scrap wood pieces held by long bolts (the kind they use for false roofing). Can be seen in the photos.

Got something to learn... Good Work Vivek
 

rbalu72

Active Member
Joined
Jan 29, 2014
Messages
107
Points
28
Location
Hyderabad
Wonderful build, congratulations!!, nice tip w.r.t clamps :)

You will not regret the build at all, FH does sound pretty good.
 

Vivek Rao

Active Member
Joined
Nov 19, 2009
Messages
193
Points
43
Location
bangalore
So after some weeks now have been able to run in the speakers for 150 + hours atleast. Had been travelling hence the run in time was also limited. Per Markaudio the papercones are supposed to go on improving right till 800 hrs... that's going to take a long long time..! Have been able to spend some time playing with the FHs and below are my initial observations..

For the Alpair7p I have now had to reduce the damping filling in the V to about 30g and in the front to about 15 to 20g. I am sure this could be optimized further after the speakers are well run in...

How do they sound ? Well for lovers of Indian classical, Western Instrumental its simply wonderful. From the audiophile dictionary I could pick out the terms Accurate, Articulate, with an excellent timing with voices having a lush texture. The instruments have the right Timbre and sound very natural. Pandit Jasraj, Gundecha Brothers, L Subramaniam, Bhajan Sopori, Kaushiki Chakrabarthy are all spending time with me :). Essentially the source has to be really good and with the right recording level for them to perform at their best.
As a back to back comparison I use my Jamo Concert 803 with a higher power tube amp in a bigger room. Clearly the Jamo have oodles of lower bass and is really able to handle the lows very well which simply cannot be expected from the FH3s. But the FHs do have a nice bass presence but in the range of 40 to 100 hz they are weak.
Take for example Eric Clapton's Unplugged album where there is an audible background of Claptons foot tapping on the stage which creates a very nice live presence for this Album - Well this is clearly very very weak in the FHs. Another example - The Valley recalls album - an excellent recording where one can hear the stage resonance when the Tabla Dagga is played is audible in the FHs but to a reduced degree. Due to this perhaps for some folks the Soundstage might appear limited with the FHs considering that the low bass is somewhat "thin".

However this is compensated by the excellent Transients response. Its magic is clearly evident in the upper midrange. Norah Jones - come away with me, Jack Johnson - Better together or Don Williams - I believe in you or even Billy McLaughlin with his fingerdance....all make my hair stand on its ends ! Wonderful stuff.
Especially enjoyable are live albums with good recording with a good voice presence - Nils Lofgren Acoustic live or Band live...to name a couple.
The controlled lowbass has had some benefits for me too. Eg say Mark Knopfler with the 5.15 AM song where there is so much prominence of the lowfrequency elements that I have found it difficult to handle in my small 14 x 12 feet room with the conventional speakers. Knopfler's voice is lost in the low bass assault. But with the FHs its handled simply wonderfully and the album is simply wonderful to listen to all over again. This listening "all over again" is repeating across many albums now :)
 

Vivek Rao

Active Member
Joined
Nov 19, 2009
Messages
193
Points
43
Location
bangalore
Some more updates here .... Had FM Sreekanth over with his various speaker cables. I felt that his silver coated copper cables really suited this setup with improved "energy levels" and clear highs. I did expect the silver do do its magic at the higher frequencies but was surprised with the overall synergy it brought in.

Later I experimented with a combination of copper and silver cables (oehlbach) I had with me. I enjoyed the benefits this brought especially in the highs but the sound was still kind of restricted (my earlier comments on lows..).

I had read the importance of rebating the front baffle behind the speaker - which I had not done in my speakers due to plain ignorance. Now however I again took time to remove the speakers and use the jigsaw, files and sandpaper to create the necessary relief for the rebate behind the speaker on the front board. Damn - its not an easy task since the boards are all fixed and the inside lining for damping material really made this a cumbersome task.

If you notice the Alpair then you would see that its got a big double magnet for the small 4 inch driver - this really reduces the space between the cone to the magnet due to which its important to provide this rebate to ensure that the air movement behind the diaphragm is easily tranferred to the rest of the box.

Wow this is now showing its effect - the speaker seems so much more open and transparent and the lows are coming out much much better. It really was worth all the efforts put....
 

apk

Well-Known Member
Joined
May 12, 2009
Messages
676
Points
63
Location
Sydney, Australia
Congratulations on this build!

I have great respect for people who 'DIY'. It needs a lot of patience and effort, especially in a country like India - where support infrastructure (for DIY work) is not very easy to come by

Best,
apk
 

HormusPeston

Member
Joined
Jan 31, 2015
Messages
94
Points
18
Location
Poona
Great work Vivek. I would suggest doing a blind A-B comparison before buying expensive cables. I did once and couldn't hear any difference between my plain copper speaker wire (relatively expensive at Rs. 40/ft) bought locally and an absurdly expensive Dutch wire (can't remember the name and they cost more than a replacement for my liver), but then my hearing is not perfect (nor is my rum-pickled liver, for that matter.) Cheers. ~HP.
 

Vivek Rao

Active Member
Joined
Nov 19, 2009
Messages
193
Points
43
Location
bangalore
expensive Dutch wire (can't remember the name and they cost more than a replacement for my liver)

Thanks HP - good one on the cable costs :) ! Quite true.
Well I am a believer in "the law of diminishing returns" and attempt to reach that point from where this law well and truly kicks in !
Since I am still tweaking my speakers and the cables ... lets see where this goes..
 

SoundCraft

Active Member
Joined
Nov 21, 2012
Messages
114
Points
28
Location
Middle Of Nowhere
Some more updates here .... Had FM Sreekanth over with his various speaker cables. I felt that his silver coated copper cables really suited this setup with improved "energy levels" and clear highs. I did expect the silver do do its magic at the higher frequencies but was surprised with the overall synergy it brought in.

Good to hear that he had dropped in with his Cables and it's results ! What sort of effect it did have on Bass,Asking cause I believe that is one of most telling fact how those cables perform !

I had read the importance of rebating the front baffle behind the speaker - which I had not done in my speakers due to plain ignorance. Now however I again took time to remove the speakers and use the jigsaw, files and sandpaper to create the necessary relief for the rebate behind the speaker on the front board. Damn - its not an easy task since the boards are all fixed and the inside lining for damping material really made this a cumbersome task.

If you notice the Alpair then you would see that its got a big double magnet for the small 4 inch driver - this really reduces the space between the cone to the magnet due to which its important to provide this rebate to ensure that the air movement behind the diaphragm is easily tranferred to the rest of the box.

Hmm isn't that a problem with thick baffles ? how thick is yours ? a Plain 19MM one's should not have much of an issue,But then again since you have already done and results are encouraging it doesn't matter now does it ?

If you could elaborate bit more about the new Sound and also shed some light on what all the Cables were bought to your place and what were their sound like ,it'll help us understand them better.

I suppose you are talking about the new one's he whipped recently ??
 

Vivek Rao

Active Member
Joined
Nov 19, 2009
Messages
193
Points
43
Location
bangalore
After a long time I have now found the Dussera long weekend quite apt to put the finishing touches on my FH3. This has taken lots of lots of hard work, time and weekends but at the end its quite satisfying to say the least.

First I considered using Veneer for finish. However while cleaning the attic I found lots of old teak pattis lying around from our house construction. Thereby the best thing was to clean this out and also complete my FH. The pattis were sorted for the best ones and plained and cut to about 7 mm thickness. These were then pasted on the FH box. This was somehow still the easy part.

Next had to do the finishing - the pattis were levelled with the angle grinder, the sides and curves finished with the router. Teak 20 mm thick strips with cut grooves served as wooded footers for the speaker. For the super tweeter used a block of teak wood shaped suitably.

After this it was insane amount of sanding, sealing, polishing, sanding, sealing, polishing..... till I got a decent finish. Now its all done ! whew ...

As to the speaker cables I am more than happy with 23 AWG CAT6 single strands - also for the short IC.
photo 1.jpg
 

sadik

Well-Known Member
Joined
Jun 14, 2015
Messages
908
Points
93
Location
Vadodara
After this it was insane amount of sanding, sealing, polishing, sanding, sealing, polishing..... till I got a decent finish. Now its all done ! whew ...
View attachment 24057

I am very well aware of this process.... Thanks to my Sanding machine:D which made my labor a lot easier.

Edit : Please Post an high resolution photo of your speakers.
 
Last edited:
Top